- •••••
YEAR = 1997
•••••
[ID ]:KL97-001
[AUTH]:Abiko Kenji
[TITL]:The Evolution of Iron
[SOUR]:Phys. Status Solidi A, 160[2] (1997), 285-296
[LAB ]:(2); Tanino
[ABST]:High-chromium iron-based alloys have attractive characteristics
compared to those of conventional ferritic steels which have been
considered to be promising candidate alloys for the next generation
machines in place of austenitic stainless steels. Their expected
properties of good corrosion resistance, low thermal stress factor,
high strength at elevated temperatures, and in some cases low
ferromagnetism are very desirable for advanced nuclear reactor
application.
[TYPE]:Ferrous Metals and Alloys
[PROP]:iron, high-purity electrolytic iron, iron alloy, mechanical property
******************************************************************************
[ID ]:KL97-002
[AUTH]:Almazouzi A.
[TITL]:Site Occupation Preference of Fe in Ni[3]Al: An Atom-Probe Study
[SOUR]:Intermetallics, 5 (1997), 37-43
[LAB ]:(2); Kyoto Univ.; National Res. Inst. for Met.; Sakurai
[ABST]:The substitution behavior of Fe in Ni[3]Al has been studied by
atom-probe microanalysis for Fe concentrations from 0.4 to 1.9 at%.
Effects of the matrix composition and annealing temperature have also
been examined. Fe atoms have been found to occupy mostly Al sites,
regardless of the Fe concentration and the matrix composition. The
present observation and the experimental results for higher Fe levels
reported in the literature are discussed in the light of the site
preference predicted by various empirical rules and theories.
[TYPE]:Ferrous Metals and Alloys
[PROP]:APFIM, Ni[3]Al, site occupancy
******************************************************************************
[ID ]:KL97-003
[AUTH]:Hirokawa Kichinosuke, Nakamura Yasushi, Abiko Kenji and Le Coze J
[TITL]:Status of the Round-Robin Analysis Test
[SOUR]:Phys. Status Solidi A, 160[2] (1997), 557-560
[LAB ]:(2); Hirokawa; Japan Energy Anal. Res. Center Co., Ltd.; Tanino; Ecole
Nationale Superieure des Mines de Saint-Etienne, Centre Sci. des
Materiaux et des Structures, France
[TYPE]:Ferrous Metals and Alloys
[PROP]:high-purity iron, trance analysis
******************************************************************************
[ID ]:KL97-004
[AUTH]:Hishinuma Akimichi, Isozaki Seiichi, Takaki Seiichi and Abiko Kenji
[TITL]:Attractive Characteristics of High-Chromium Iron-Based Alloys for
Nuclear Reactor Application
[SOUR]:Phys. Status Solidi A, 160[2] (1997), 431-440
[LAB ]:(2); Tokai Res. Inst., JAERI; Tanino
[ABST]:Electrolytic iron is the important mother material for the fundamental
research of iron and its alloys. Recently, the purification of
electrolytic iron form a purity of 99.9 to 99.998 mass% has been
achieved. Properties such as ductility, strength, and recrystallization
temperature of the high-purity material are quite different from the
accepted values of conventional electrolytic iron. The ductility of
high-purity iron and its alloys is strongly affected by trace
impurities such as carbon, nitrogen, sulfur, phosphorus, etc. It is
found that phosphorus, etc. It is found that phosphorus improves
remarkably the ductility of iron above 773K, although it causes
intergranular fracture at low temperatures. On the other hand, 5 mass
ppm of sulfur in iron suffices to reduce strongly the hot ductility of
iron between 673 and 1173K. It is concluded that the limit of soluble
sulfur in iron with excellent hot ductility is less than 1 mass ppm.
The ductility of Fe-50 mass% Cr alloy between room temperature and 1573
K is improved by the purification. The reduction of the nitrogen
content suppresses the formation of sigma phase in the Fe-50 mass% Cr
alloy.
[TYPE]:Ferrous Metals and Alloys
[PROP]:high purity iron-chromium alloy, stress corrosion cracking, creep
strength, thermal stress factor
******************************************************************************
[ID ]:KL97-005
[AUTH]:Hosoda Hideki, Mizuuchi Kiyoshi and Inoue Kanryu
[TITL]:The Effect of Hydrogen on the Hardness of Fe-Al Alloys
[SOUR]:JOM, [8] (1997), 56-59
[LAB ]:(2); Hanada; Osaka Municipal Technical Res. Inst.; Univ. of Washington
[ABST]:Fe-Al alloys show environmental embrittlement related to hydrogen
generated during the reaction of aluminum with water vapor. To
investigate this relationship, micro-hardness measurements were made
from alloys subjected to two different conditions after a drying
treatment: holding at room temperature in a wet environment (dry-wet
treatment) and holding in a wet environment followed by a dry treatment
at 423 K (dry-wet-dry treatment). In the former case, and age-hardening
phenomenon is observed; in the latter, an age-softening phenomenon is
observed. Such changes in hardness are reversible in response to
environmental conditions.
[TYPE]:Ferrous Metals and Alloys
[PROP]:hydrogen, hardness, Fe-Al alloy, diffusivity
******************************************************************************
[ID ]:KL97-006
[AUTH]:Isozaki Seiichi and Abiko Kenji
[TITL]:Role of Tungsten for the Mechanical Properties of High-Purity Fe-50
mass% Cr Alloys at Elevated Temperatures
[SOUR]:Phys. Status Solidi A, 160[2] (1997), 469-479
[LAB ]:(2); Tanino
[ABST]:The effect of tungsten on the mechanical properties and the
microstructure of high-purity Fe-50 mass% Cr alloys was investigated by
tensile tests and by optical microscopy in the temperature range
between 873 and 1073 K. The yield stress increased by the addition of W
at temperatures above 873 K, especially above 973 K, due to the
solid-solution hardening mechanism. A W-free alloy tested above 873 K
failed by intergranular fracture and the reduction of area was below
60%. On the other hand, an alloy doped with 8 mass% W showed
transgranular fracture above 873 K and the reduction of area was more
than 70%. The addition of W suppressed the nucleation of cavities at
grain boundaries.
[TYPE]:Ferrous Metals and Alloys
[PROP]:high-purity Fe-50 Cr alloy, tungsten, mechanical property, tensile test
******************************************************************************
[ID ]:KL97-007
[AUTH]:Tetsui Toshimitsu, Shinohara Masaomi and Abiko Kenji
[TITL]:Aging Properties of Ultra-High-Purity Fe-High-Cr Alloys
[SOUR]:Phys. Status Solidi A, 160[2] (1997), 459-467
[LAB ]:(2); Nagasaki R & D Center, Mitsubishi Heavy Industries Ltd.; Tanino
[ABST]:The paper investigates the secondary phase precipitation behavior as
well as changes in mechanical properties accompanying the again
treatment of two types of high-Cr alloys (Fe-50Cr and Fe-30Cr-4W)
having different purity and additional impurities. The results show
that ultra-high purification can prevent the sigma-phase formation even
after aging. Carbon and nitrogen are hardly dissolved in the base phase
and they do not bring about the formation of the sigma phase. The
differences in the formation mechanisms of sigma and Laves phases,
representative harmful phases of Fe-high-Cr alloys, are discussed.
[TYPE]:Ferrous Metals and Alloys
[PROP]:high-purity iron-chromium alloy, [sigma] phase, charpy impact test,
tensile test
******************************************************************************
[ID ]:KL97-008
[AUTH]:Wakai Eiichi, Hishinuma Akimichi, Sawai Tomotsugu, Kato Yasushi,
Isozaki Seiichi, Takaki Seiichi and Abiko Kenji
[TITL]:Effects of Neutron Irradiation on Tensile Properties in High-Purity
Fe-Cr Alloys
[SOUR]:Phys. Status Solidi A, 160[2] (1997), 441-448
[LAB ]:(2); Dept. of Mater. Sci. Eng., JAERI; Tanino
[ABST]:The tensile properties of high- and low-purity Fe-9,-18 and -30Cr
alloys irradiated by neutrons up to a dose of 5 times 10]24[ n/m]2[ (E
] 1MeV) at 613, 673, or 763K have been examined. The yield strength and
the ultimate strength are increased and the elongation is decreased by
irradiation. The enhancement of these strengths due to the irradiation
has a tendency to increase with chromium and impurity content. Large
stress drops are often observed, especially at 763 K, in stress-strain
curves of high-purity and high-chromium-content alloys except for
Fe-9Cr alloys. Irradiation-induced precipitates, with 2% larger
interplanar spacings than the alpha'-phase, on dislocation loops are
more easily formed in the specimens of higher chromium content and
higher purity. The precipitates are formed even in the irradiated
Fe-9Cr alloy of high purity. The stress drop behavior during the
tensile tests is predominant in the specimens of higher chromium
content and higher purity.
[TYPE]:Ferrous Metals and Alloys
[PROP]:high purity iron-chromium alloy, neutron irradiation, mechanical
property, TEM microstructure
******************************************************************************
[ID ]:KL97-009
[AUTH]:Yano Koji and Abiko Kenji
[TITL]:Formation of sigma Phase in Highly Purified Fe-Cr Alloys
[SOUR]:Phys. Status Solidi A, 160[2] (1997), 449-457
[LAB ]:(2); Technical Res. Lab. Kawasaki Steel Co.; Tanino
[ABST]:The formation behavior of the sigma phase in Fe-Cr alloys was
investigated using highly purified Fe-Cr alloys containing between 40
and 50 mass% chromium. The amount of sigma phase was determined by
optical microscopy. In annealed highly purified Fe-40 and 45 mass% Cr
alloys, the sigma phase nucleates at the surface of the specimen and
grows inward, and the formation of this phase is finished completely
within 360 ks. In annealed highly purified Fe-50 mass% Cr alloy the
nucleation rate and the growth rate of the sigma phase were extremely
small. The formation of the sigma phase was suppressed by purification,
by the reduction of nitrogen, and by the presence of a small amount of
carbon.
[TYPE]:Ferrous Metals and Alloys
[PROP]:high-purity iron-chromium alloy, [sigma] phase, microstructure
******************************************************************************
[ID ]:KL97-010
[AUTH]:Ringer Simon P., Hono Kazuhiro, Sakurai Toshio and Polmear Ian J.
[TITL]:Cluster Hardening in an Aged Al-Cu-Mg Alloy
[SOUR]:Scr. Mater., 36[5] (1997), 517-521
[LAB ]:(2); Monash Univ.; National Res. Inst. for Met.; Sakurai; Emeritus
Prof., Monash Univ.
[TYPE]:Non-Ferrous Metals and Alloys
[PROP]:alloy, APFIM, HRTEM
******************************************************************************
[ID ]:KL97-011
[AUTH]:Suwarno Hadi, Yamamoto Takuya, Ono Futaba, Yamaguchi Kenji and Yamawaki
Michio
[TITL]:Hydrogen Desorption Properties of Hydrogenated U-Th-Zr Alloys
[SOUR]:J. Nucl. Mater., 247 (1997), 333-338
[LAB ]:(1); Univ. of Tokyo; Oarai; Matsui
[ABST]:Hydrogen desorption properties of hydrogenated U-Th-Zr alloys of varied
compositions were investigated using a hydrogen absorption-desorption
experimental system, TG-DTA and DSC analyzers. Isothermal desorption at
900Ž of elemental ratio U:Th:Zr:H=1:1:4:9.5 exhibited that there were
two distinct plateau regions identified as ZrH[1.4]-ZrH and
ThZr[2]H[7-x]-ThZr[2] systems. TG-DTA and DSC measurements under the
temperature range from room temperature to 1000Ž have shown that there
were three endothermic peaks identified as dehydrogenation reactions of
ZrH[2-x]-ZrH and ThZr[2]H[7-X]. The DTA curve identified the first peak
area as the ZrH[1.4]-ZrH system, while the DSC curves identified that
the second peak is the decomposition of ZrH and the third peak is the
decomposition of ThZr[2]H[7-x]. It was also shown that both ZrH[2-x]
and ThZr[2]H[7-x] are more stable in the alloy than the pure ones.
Measured enthalpy changes during decomposition of the hydrogenated
U-Th-Zr alloy are similar to the theoretical calculation. Oxidation
during measurement of the U:Th:Zr:H = 2:1:6:13.1 resulted in a
different measured enthalpy change and calculation. Isothermal
decomposition of the U:Th:Zr:H =1:1:4:9.5 without any disintegration
indicates stability of the alloy against powdering on
hydriding-dehy-driding cycles. Stability of the samples at high
temperature similar to that of U-ZrH[1.6] for TRIGA fuel can be
maintained after the first decomposition.
[TYPE]:Non-Ferrous Metals and Alloys
[PROP]:U-Th-Zr alloy, hydrogen desorption, TG-DTA, DSC, p-c isotherm
******************************************************************************
[ID ]:KL97-012
[AUTH]:Umakoshi Yukichi, Fujitani Wataru, Nakano Takayoshi, Inoue Akihisa,
Ohtera Katsumasa, Mukai Toshizi and Higashi Kenji
[TITL]:Microstructure Evolution During High-Strain-Rate Superplastic Flow in
Al-Ni-Misch Metal Alloy Produced from Amorphous Powders
[SOUR]:THERMEC'97: Proc. Int. Conf. Thermomechanical Processing of Steels &
Other Materials, ed. by T. Chandra and T. Sakai, (1997), 1983-1989
[LAB ]:(2); Dept. of Mater. Sci. and Eng., Faculty of Eng., Osaka Univ.;
Inoue; YKK; Osaka Municipal Technical Res. Inst.; Osaka Prefecture
Univ.
[ABST]:Changes in microstructure and deformation substructure in Al-14mass%
Ni-14mass% misch metal alloy produced from amorphous powders were
investigated during superplastic deformation at a high-strain-rate of
1s]-1[ at 873K. Grain refinement occurred and the frequency of small
angle boundaries increased in superplastically deformed specimens.
Dynamic recovery and recrystallization occurred. Dislocations were
observed in grains and were annihilated at grain boundaries during
superplastic deformation. High-strain-rate superplasticity was mainly
controlled by grain boundary sliding. Dislocations played an important
role in the accommodation of residual stress induced by the grain
boundary sliding. Small precipitates of Al[3]Mm and Al[3]Ni effectivaly
suppressed the grain growth during annealing and acted as nucleation
and/or annihilation sites of dislocations.
[TYPE]:Non-Ferrous Metals and Alloys
[PROP]:aluminum base alloy, powder metallurgy, amorphous powder, high strain
rate superplasticity, superplastic structure
******************************************************************************
[ID ]:KL97-013
[AUTH]:Yamamoto Takuya, Suwarno Hadi, Kayano Hideo and Yamawaki Michio
[TITL]:Development of New Reactor Fuel Materials: Hydrogenation Properties of
U-Th-Z r Alloys and Neutron Irradiation Effects on Their Hydrides
[SOUR]:J. Nucl. Mater., 247 (1997), 339-344
[LAB ]:(1); Oarai; Matsui; Univ. of Tokyo
[ABST]:Hydrogen absorption properties of four U-Th-Zr alloys with compositions
of 2:1:6, 1:1:4, 1:2:6 and 1:4:10 in U:Th:Zr ratio were examined for
developing a new U-Th mixed hydride fuel. It was revealed by hydrogen
absorption measurement that for all the specimens hydrogen capacities
normalized by the sum of Th and Zr contents were similar to or higher
than that of the U-ZrH[2-x] alloy, TRIGA fuel, at temperatures form 773
to 1073 K and under hydrogen pressures from 10]2[ to 10]5[ Pa.
Regarding the microstructure, the alloy hydrides consisted of three
phases; alpha-U, ZrH[2-x] and ThZr[2]H[7-x], which are finely and
homogeneously mixed with each other probably because they were formed
form one solid solution phase stable at high temperatures. In the case
of Th-rich alloys the alpha-U was about 1 mu m in diameter and
dispersed in the bulk of ThZr[2]H[7-x] and ZrH[2-x]. Such
microstructure is quite similar to that of U-ZrH[2-x] fuel. The
hydrides irradiated to 7.4 times 10]23[ n/m]2[ in the reactor showed a
high phase stability.
[TYPE]:Non-Ferrous Metals and Alloys
[PROP]:U-Th-Zr alloy, hydrogen absorption, microhardness, neutron irradiation
******************************************************************************
[ID ]:KL97-014
[AUTH]:Yamamoto Takuya, Suwarno Hadi, Kayano Hideo and Yamawaki Michio
[TITL]:Studies on Hydrogen Absorption-Desorption Properties of U-Th-Zr Alloys
for Developing New Reactor Fuel Materials
[SOUR]:Sci. Rep. RITU, A45[1] (1997), 57-62
[LAB ]:(1); Oarai; Univ. of Tokyo
[ABST]:In order to develop a new U-Th mixed hydride fuel, hydrogen absorption
properties of four U-Th-Zr alloys with compositions of 2:1:6, 1:1:4,
1:2:6 and 1:4:10 in U:Th:Zr ratio were examined at temperatures from
773 to 1173 K and under hydrogen pressures from 10]2[ to 10]5[ Pa.
Hydrogen capacities normalized by the sum of Th and Zr contents of all
the specimens were similar to or higher than that of U-ZrH[2-x] alloy
which has been utilized as a TRIGA fuel. Regarding the microstructure,
the alloy hydrides consisted of three phases; alpha-U, ZrH[2-x] and
ThZr[2]H[7-x], which are finely and homogeneously mixed with each other
probably because they were formed form one solid solution phase stable
at high temperatures. In the case of Th-rich alloys the alpha-U was
about 1mu m in diameter and dispersed in the bulk of ThZr[2]H[7-x] and
ZrH[2-x]. Such microstructure is quite similar to that of U-ZrH[2-x]
fuel. Hydrogen desorption properties examined on the 1:1:4 alloy showed
better holding of hydrogen than ZrH[2-x] at 1173 K.
[TYPE]:Non-Ferrous Metals and Alloys
[PROP]:U-Th-Zr alloy, hydrogen absorption-desorption, X-ray diffraction, SEM
******************************************************************************
[ID ]:KL97-015
[AUTH]:Zhang Qiwu, Sugiyama Kazumasa and Saito Fumio
[TITL]:Enhancement of Acid Extraction of Magnesium and Silicon from Serpentine
by Mechanochemical Treatment
[SOUR]:Hydrometallurgy, 45[3] (1997), 323-331
[LAB ]:(2); Inst. for Adv. Mater. Process., Tohoku Univ.; Hiraga
[ABST]:Acid leaching of serpentine ground for various times was conducted at
room temperature using 1 N HCl and 1 N H[2]SO[4] solutions,
respectively. Dry grinding of the ore sample by a planetary ball mill
results in a structural change from a crystalline state into an
amorphous one. This change is attributed to local disordering around
magnesium in the structure. This disordering leads to enhancement of
extraction of both magnesium and silicon from the mechanically
activated serpentine by the acid solutions. Concentrations of both
elements in the mother solutions increase with an increase in grinding
time. More than 90% of Mg and 70% of Si in the sample ground for 240
min can be extracted by leaching, while no significant extraction is
achieved in the leaching of the non-activated sample. The (Mg/Si) molar
ratio in the mother solution decreases as grinding progresses. The
ratio levels off under prolonged grinding and is equivalent to almost
two, which is the same as that for forsterite.
[TYPE]:Non-Ferrous Metals and Alloys
[PROP]:serpentine, extraction, mechanochemistry
******************************************************************************
[ID ]:KL97-016
[AUTH]:Goto Takashi, Sasaki Takuya and Hirai Toshio
[TITL]:High Temperature Corrosion of Stainless Steel, Inconel and Incoloy
Alloys in Bromine-Containing Atmosphere (in Japanese)
[SOUR]:Nippon Kinzoku Gakkaishi (J. Jpn. Inst. Met.), 61[5] (1997), 430-436
[LAB ]:(2); Hirai
[ABST]:Practical heat-resisting alloys such as stainless steel 304, Inconel
625 and Incoloy 825 showed a significant mass loss (active corrosion)
and a mass gain (passive corrosion), respectively, at a low and a high
oxygen partial pressure in a bromine-containing atmosphere around
1000K. The transition oxygen partial pressures from the active to
passive corrosion for these alloys were about 0.05 to 0.2 kPa at 1073
K. This result was almost in agreement with the thermodynamic
calculations by an optimization method. The addition of water vapor
(P[H[2]O] = 1.17kPa) at 1073 K and P[O[2]] = 0.063 kPa caused the
change from the active to passive corrosion for stainless steel 304 but
not for Inconel 625. This behavior was also explained with the
thermodynamic calculations.
[TYPE]:Non-Ferrous Metals and Alloys
[PROP]:bromine, water vapor, stainless steel, inconel, incoloy
******************************************************************************
[ID ]:KL97-017
[AUTH]:Kato Hiroaki, Murao Satoshi, Miyazaki Terunobu and Motokawa Mitsuhiro
[TITL]:Atomic Ordering and High-Field Magnetization in Rapidly-Quenched Ni-Mn
Alloys (in Japanese)
[SOUR]:Nippon Oyo Jiki Gakkaishi (J. Magn. Soc. Jpn.), 21[4-2] (1997), 381-384
[LAB ]:(2); Dept. of Appl. Phys., Faculty of Eng., Tohoku Univ.; Osaka Res.
Lab., Sumitomo Electric Industries, Ltd.;; Motokawa
[ABST]:Magnetization measurements in steady fields of up to 300 kOe were
performed for disordered and ordered Ni[1-x]Mn[x] alloys prepared by
rapid quenching and subsequent annealing, in order to study the
correlation between atomic ordering and magnetic properties. The
high-field susceptibility of the rapid-quenched samples exhibited a
maximum near x=0.25, while that for the annealed samples had a distinct
minimum also near x=0.25. Magnetization isotherms at 4.2 K for
rapid-quenched samples with 0.19 leq x leq 0.34 revealed the existence
of considerable hysteresis, suggesting the existence of spin-glass-like
states. The temperature dependence of low-field magnetization for the
same samples exhibited typical freezing behavior at low temperatures,
namely, an irreversibility of field-cooled and zero-field-cooled
magnetization. The freezing temperature was found to increase with
increasing Mn content x.
[TYPE]:Non-Ferrous Metals and Alloys
[PROP]:Ni-Mn alloys, high field effect
******************************************************************************
[ID ]:KL97-018
[AUTH]:Cho Meoung Whan, Koh Kwang Wook, Morikawa Keiji, Arai Kenta, Jung Hyun
Don, Zhu Ziqiang, Yao Takafumi and Okada Yasumasa
[TITL]:Surface Treatment of ZnSe Substrate and Homoepitaxy of ZnSe
[SOUR]:J. Electron. Mater., 26[5] (1997), 423-428
[LAB ]:(2); Yao; Electrotechnical Lab.
[ABST]:High quality ZnSe(100) substrates have been used for homoepitaxial
growth by molecular beam epitaxy. A chemical pretreatment suitable for
ZnSe substrate preparation is determined from x-ray photoemission
spectroscopy studies. Thermal cleaning processes for the ZnSe(100)
surface were investigated by in-situ reflection high energy electron
diffraction and the surface phase diagram for ZnSe(100) was obtained
for the first time. The low temperature photoluminescence spectra
recorded from homoepitaxial layers exhibit unsplit free and bound
exction transitions with strong intensities. The full widths at half
maximum of the (400) x-ray diffraction spectra for ZnSe homoepitaxial
layer were 17sim31 arcsec.
[TYPE]:Intermetallic Compounds
[PROP]:ZnSe, MBE, homoepitaxy
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[ID ]:KL97-019
[AUTH]:Emori Hiroshi, Takasugi Takayuki and Hiraga Kenji
[TITL]:High-Resolution Electron Microscopy of Grain Boundaries in
Ni[3](Al[0.8]Ti[0.2]) Bicrystals I. [001] Small-Angle Tilt Boundaries
[SOUR]:Philos. Mag. A, 75[5] (1997), 1403-1416
[LAB ]:(2); Hiraga; Hanada
[ABST]:The grain-boundary structure of [001] small-angle tilt boundaries in
Ll[2]Ni[3] (Al[0.8]Ti[0.2]) bicrystals prepared by hot pressing was
investigated by high-resolution transmission electron microscopy.
Dislocations with a Burgers vector a [100] which are dissociated into
two superpartials with Burgers vectors (a/2)[110] and (a/2)[110]
connected by an antiphase boundary (APB) were found. The dissociated
superpartials and the corresponding APB lie along the grain-boundary
plane. The cores of the dissociated superpartials extend (or spread)
over a few {011} atomic planes. Also, the preferred configuration of
the dislocation array observed was discussed on energy considerations.
[TYPE]:Intermetallic Compounds
[PROP]:Ni[3](Al,Ti) alloy, grain boundary structure, high resolution, electron
microscopy, small angle boundary
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[ID ]:KL97-020
[AUTH]:Hiraoka Kouichi, Kojima Kenichi, Shinohara Takeshi, Hihara Tadamiki and
Wachter P.
[TITL]:]77[Se NMR Study of CeSe
[SOUR]:Physica B, 230-232 (1997), 133-135
[LAB ]:(2); Faculty of Eng., Oita Univ.; Faculty of Integrated Arts and Sci.,
Hiroshima Univ.; Yamayasu; Dept. of General Edu., Fukuyama Univ.; Lab.
fur Festkorperphysik, ETH Zurich
[ABST]:The ]77[Se Knight shift K(T) in CeSe exhibits a Curie- Weiss-like
behavior above 20K, and a plot of K(T) against susceptibility yields a
hyperfine field of 11.0 kOe/mu[B]. The nuclear spin-lattice relaxation
rate T[1]]-1[ is independent of temperature at high temperatures. The
NMR results suggest the localized nature of Ce 4f electrons.
[TYPE]:Intermetallic Compounds
[PROP]:CeSe, NMR, knight shift, dense Kondo
******************************************************************************
[ID ]:KL97-021
[AUTH]:Hosoda Hideki, Fukui Toshihiko, Inoue Kanryu, Mishima Yoshinao and
Suzuki Tomoo
[TITL]:Change of M[s] Temperatures and Its Correlation to Atomic
Configurations of Offstoichiometric NiTi-Cr and NiTi-Co Alloys
[SOUR]:Mater. Res. Soc. Symp. Proc., 459 (1997), 287-294
[LAB ]:(2); Hanada; NKK Co.; Dept. of Mater. Sci. and Eng., Univ. of
Washington; Prof. Emeritus, Tokyo Inst. of Technol.
[ABST]:Effects of compositional deviation from the stoichiometry and Cr and Co
additions on martensitic-transformation-start and austenite-start
temperatures (M[s] and A[s]) of offstoichiometric NiTi alloys are
investigated. M[s] and A[s] are determined using conventional
differential thermal analysis (DTA), where the temperature range
investigated is between 77K and 423K. Alloys are widely chosen with
both Ni- and Ti-rich compositions, to which ternary elements, Cr and
Co, are added. It is clearly shown that M[s] and A[s] in single phase
regions are reduced with increasing amount of constituent element, Ni,
and ternary elements, Cr and Co. On the other hand, M[s] and A[s] do
not depend on Ti concentration when Ti concentration is more than
52mol.%. NiTi alloys are in two phase region in the case. M[s] changes
by Co at offstoichiometry are evaluated to be -15K/mol.% in Ni poor
side and -30K/mol.% in Ni rich side. These values correspond to
-22K/mol.% for the stoichiometric NiTi alloys. Also, effects of Cr on
M[s] are evaluated to be -65K /mol.% in Ni poor side and -45K/mol.% in
Ni rich side. The former is similar to the M[s] change in
stoichiometric alloys, and the latter is close to our prediction of
-30K/mol.% in comparison with the reported value of -120K/mol.% for
stoichiometric alloys. It is concluded for offstoichiometric NiTi
alloys that effects of ternary additions on M[s] can be explained using
electronic NiTi alloys. Effect of degree of order is also discussed.
[TYPE]:Intermetallic Compounds
[PROP]:NiTi alloys, M[s] temperature, atomic configuration, site occupation,
electron atom ratio
******************************************************************************
[ID ]:KL97-022
[AUTH]:Hosoda Hideki, Mishima Yoshinao and Suzuki Tomoo
[TITL]:Anomalous Temperature Dependence of Yield Stress and Work Hardening
Coefficient of B2-Stabilized NiTi Alloys
[SOUR]:Mater. Res. Soc. Symp. Proc., 460 (1997), 635-640
[LAB ]:(2); Hanada; Precision and Intelligence Lab., Tokyo Inst. of Technol.;
Prof. Emeritus, Tokyo Inst. of Technol.
[ABST]:Yield stress and work hardening coefficient of B2-stabilized NiTi
alloys are investigated using compression tests. Compositions of NiTi
alloys are based on Ni-49mol.%Ti, to which Cr, Co and Al are chosen as
ternary elements which reduce martensitic transformation temperatures
of the B2 phase. Mechanical tests are carried out in liquid nitrogen at
77K, air at room temperature (R.T.) and in an argon atmosphere between
473K and 873K. Only at 77K, some alloys show characteristic
stress-strain curves which indicate stress induced martensitic
transformation (SIMT), but the others do not. Work hardening
coefficient is found to be between 2 and 11Gpa in all the test
temperature range. The values are extremely high compared with Young's
modulus of B2 NiTi. Yield stress and work hardening coefficient
increase with test temperature between R.T. and about 650K in most
alloys. The anomalous temperature dependence of mechanical properties
is not related to SIMT but to precipitation hardening and/or anomalous
dislocation motion similar to B2-type CoTi. Solution hardening by
adding ternary elements is evaluated to be small for Cr and Co
additions, and large for Al addition, depending on difference in atomic
size of the ternary element with respect to Ni or Ti.
[TYPE]:Intermetallic Compounds
[PROP]:NiTi alloys, B2 structure, yield stress, work hardening coefficient
******************************************************************************
[ID ]:KL97-023
[AUTH]:Hosoda Hideki, Semboshi Satoshi and Hanada Shuji
[TITL]:Powder Preparation by Hydrogenation of Nb-Al Alloys
[SOUR]:Proc. Int. Symp. Designing, Processing and Properties of Advanced
Engineering Materials, (1997), 307-312
[LAB ]:(3); Hanada
[ABST]:Pulverization by hydrogenation and hydrogen absorption in Nb-Al alloys
consisting of Nb solid solution (Nb[ss]), Nb[3]Al and Nb[2]Al were
studied by measuring pressure-composition isotherms (PCT curves) under
the hydrogen pressure from 0 to 3.4MPa at 353K and 357K, along with
microstructural observation and X-ray diffraction analysis. It has been
found that (1) single phase alloys are not pulverized regardless of
considerable amount of hydrogen absorption, (2) Al addition to Nb in a
bcc solid solution range reduces hydrogen absorption, (3) two phase
alloys are pulverized when rapid hydrogen absorption appears at a
constant pressure, and (4) Nb[3]Al/Nb[2]Al alloy absorbs larger amount
of hydrogen than Nb[3]Al/Nb[ss] alloy. Based on the measured lattice
parameter of Nb[ss] as a function of Al content, hydrogen diffusivity
is discussed.
[TYPE]:Intermetallic Compounds
[PROP]:Nb[3]Al, niobium solid solution, hydrogenation, hydrogen absorption,
hydrogen diffusivity, lattice parameter
******************************************************************************
[ID ]:KL97-024
[AUTH]:Hosoda Hideki, Takahashi Tohru, Takehara Masaharu, Kingetsu Toshiki and
Masumoto Hiroki
[TITL]:Phase Stability and Mechanical Properties of IrAl Alloys
[SOUR]:Mater. Trans., JIM, 38[10] (1997), 871-878
[LAB ]:(2); Hanada; Jpn. Ultra-high Temp. Mater. Res. Inst.(JUTEMI); Carbon
Mater. Dept., Nippon Steel Chem. Co. Ltd.; Steel & Technol. Developt.
Lab., Nisshin Steel Co. Ltd.
[ABST]:Phase stability and mechanical properties of B2 type IrAl intermetallic
alloys are investigated. Three types of IrAl alloys are obtained by
arc-melting, followed by homogenization at 2023K for 14.4ks in vacuum,
and are slowly cooled for removing thermal vacancies. Phase stability
is using optical microscopy, X-ray diffractometry and differential
thermal analysis up to 1973K. Mechanical properties are investigated by
micro-Vickers hardness measurements at room temperature and compression
tests up to 1873 K. All alloys after heat treatment have eutectic
structures composed of B2-IrAl and fcc Ir solid solution: B2 IrAl is
the primary phase and Ir solid solutions exist at grain boundaries.
Lattice parameters of both phases are calculated to be 298.8pm for B2
IrAl and 384pm for fcc Ir solid solutions. Micro-Vickers hardness is
measured to be H[v] 1050 in average, H[v] 1100 through 700 for eutectic
structures. Although all alloys show brittleness at room temperature,
compressive ductility appears over 1273 K. 0.2% flow stress decreases
rapidly with increasing test temperatures: 90 MPa at 1473 K and 30 MPa
at 1873 K. It is concluded: (1) IrAl/Ir eutectic structures are induced
through solidification, and the eutectic structures remain through the
homogenization treatment, and (2) the strength and specific strength of
IrAl alloys are higher than those of other intermetallics such as NiAl,
Ni[3]Al and TiAl.
[TYPE]:Intermetallic Compounds
[PROP]:phase stability, mechanical properties, IrAl
******************************************************************************
[ID ]:KL97-025
[AUTH]:Legros Marc, Minonishi Yasuhide and Caillard Daniel
[TITL]:An in-situ Transmission Electron Microscopy Study of Pyramidal Slip in
Ti[3]Al I. Geometry and Kinetics of Glide
[SOUR]:Philos. Mag. A, 76[5] (1997), 995-1011
[LAB ]:(2); Centre d'Elaboration des Materiaux et d'Etudes Struct., Lab.
d'Optique Electronique, CNRS; Matsui
[ABST]:Ti[3]Al single crystals have been strained along the c axis in situ in
a transmission electron microscope, in order to investigate the
mechanisms of glide in pyramidal planes. Between -150 and 400Ž,
superdislocations are shown to dissociate into two superpartials with
c+a/2 Burgers vectors. They glide in the type I pyramidal (pi[1])
planes, in contrast with type II pyramidal (pi[2]) planes observed in
macroscopic compression along the c axis. This difference is proposed
to result from the reversal of the applied stress. Glide softening
takes place, probably associated with intensive disordering in the slip
plane. The most mobile dislocations are 30Kin character lying parallel
to the second c+a/2 direction in the slip plane other than the Burgers
vectors. The least mobile are, on average, heavily cusped
60Kdislocations which nucleate a high density of rows of loops. It is
concluded that the critical resolved shear stress of pi[1] slip is
determined by the density of pinning points on the less mobile
dislocations.
[TYPE]:Intermetallic Compounds
[PROP]:intermetallics, Ti[3]Al, in-situ TEM observation, pyramidal slip, super
dislocations, tension/compression asymmetry
******************************************************************************
[ID ]:KL97-026
[AUTH]:Legros Marc, Minonishi Yasuhide and Caillard Daniel
[TITL]:An in-situ Transmission Electron Microscopy Study of Pyramidal Slip in
Ti[3]Al II. Fine Structure of Dislocations and Dislocation Loops
[SOUR]:Philos. Mag. A, 76[5] (1997), 1013-1032
[LAB ]:(2); Centre d'Elaboration des Materiaux et d'Etudes Struct., Lab.
d'Optique Electronique, CNRS; Matsui
[ABST]:An in-situ transmission electron microscopy investigation has been
conducted of the dynamic behavior of dislocations in the type I
pyramidal (pi[1]) slip plane of Ti[3]Al single crystals which operates
when specimens are strained in tension along the c-axis. Superpartial
dislocations are split asymmetrically into two unlike partials. The
high-energy complex stacking fault involved is thought to relax by
short-range diffusion and this can account for the very strong
disordering, the glide softening, and the nucleation of loops reported
in part I. Three loop families have been identified, all vacancy type.
Mechanisms are proposed to explain the formation of loops, their
interactions with mobile dislocations, and their alignment along a
c+a/2 direction which is direction which is different from the Burgers
vector direction of the gliding dislocations. It is concluded that the
critical resolved shear stress of pyramidal slip is determined by the
nucleation process of loops.
[TYPE]:Intermetallic Compounds
[PROP]:intermetallics, Ti[3]Al, in-situ TEM observation, pyramidal slip, super
dislocations, tension/compression asymmetry, dislocation loops
******************************************************************************
[ID ]:KL97-027
[AUTH]:Minonishi Yasuhide
[TITL]:Microstructures of Pyramidal Slip Dislocations in Ti[3]Al Single
Crystals Compressed Along the C Axis
[SOUR]:THERMEC'97: Proc. Int. Conf. Thermomechanical Processing of Steels &
Other Materials, ed. by T. Chandra and T. Sakai, (1997), 1511-1517
[LAB ]:(3); Matsui
[ABST]:The [-1 -1 2 6]{1 1 -2 1} pyramidal slip in Ti[3]Al shows the so-called
yield stress anomaly. A marked change in dislocation configuration is
observed in the temperature range of anomaly; dislocations observed at
-70Ž, the lowest temperature concerned, are ordinary pairs of
superpartials coupled by the antiphase boundary (APB) and elongated
mostly along the edge orientation. At the other extreme temperatures,
e.g., 700Ž, pairs of unlike edge superpartials coupled by the APBs are
observed. This change in dislocation configurations is interpreted as
resulting from a change in mechanisms of dislocation generation
depending on the deformation temperature; dislocations are generated as
superdislocations in a lower temperature range and as superpartial
dislocations in a higher temperature range. These observations are
discussed in terms of the immobilization of edge c+a/2 superpartials by
climb dissociation onto the basal plane following a reaction: 1/6[-1 -5
2 6] -] 1/6[-1 0 1 3] + 1/6[0 -1 1 3].
[TYPE]:Intermetallic Compounds
[PROP]:intermetallics, Ti[3]Al, super dislocations, climb dissociation of
dislocations, generation mechanism of dislocations, super partials
******************************************************************************
[ID ]:KL97-028
[AUTH]:Murayama Yonosuke and Hanada Shuji
[TITL]:Solid Solution Hardening of Nb[3]Al Alloys Containing Tungsten,
Molybdenum and Tantalum
[SOUR]:Scr. Mater., 37[7] (1997), 949-953
[LAB ]:(3); Hanada
[TYPE]:Intermetallic Compounds
[PROP]:Nb[3]Al, Solid solution, hardening, phase diagram
******************************************************************************
[ID ]:KL97-029
[AUTH]:Sluiter Marcel, Takahashi Manabu and Kawazoe Yoshiyuki
[TITL]:Theoretical Study of Phase Stability in LaNi[5]-LaCo[5] Alloys
[SOUR]:J. Alloys Compd., 248 (1997), 90-97
[LAB ]:(2); Dept. of Phys., Upton; Gunma Univ.; Kawazoe
[ABST]:The phase stability of LaNi[5]-LaCo[5] alloys with the CaCu[5] type
crystal structure (P/6/mmm) has been investigated from first
principles. The alloy is computed to from a continuous solid solution.
Ferromagnetism increases with Co concentration, in accordance with
experimental observations. It is found that Co impurities in LaNi[5]
have a strong preference for the three-fold degenerate non-basal sites
(Ni-II, 3g). This preference persists at high temperatures, as has been
observed in actual alloys by neutron scattering. The softness in the c
direction is shown to increase with increasing Co concentration in the
alloy.
[TYPE]:Intermetallic Compounds
[PROP]:LaNi[5]-LaCo[5], CVM(cluster variation method), KKR, ferromagnetism,
site preference
******************************************************************************
[ID ]:KL97-030
[AUTH]:Takasugi Takayuki and Hiraga Kenji
[TITL]:Grain Boundary Brittleness, and Grain Boundary Structure and Chemistry
of Ni[3]Al Intermetallics
[SOUR]:Proc. Int. Symp. Nickel and Iron Aluminides: Processing, Properties,
and Applications, ed. by S.C. Deevi et al., Cincinati, 1996, (1997),
33-49
[LAB ]:(2); Hanada; Hiraga
[ABST]:Intrinsic grain boundary brittleness of Ni[3]Al is first described on
the basis of recently progressed observations by HREM, FIM and AES, and
theoretical calculations and modelings. Also, extrinsic grain boundary
brittleness of Ni[3]Al due to hydrogen invaded from environment is
described on the basis of recently performed observations where test
environment and material processing were carefully controlled. Then,
how alloying elements affect intrinsic and extrinsic grain boundary
brittleness of Ni[3]Al is discussed. It is emphasized that Ni[3]Al is
not so brittle as has been thought, and therefore could be ductilized
by alloying, careful processing and elimination of harmful hydrogen.
[TYPE]:Intermetallic Compounds
[PROP]:Ni[3]Al, grain boundary brittleness, grain boundary structure, grain
boundary chemistry
******************************************************************************
[ID ]:KL97-031
[AUTH]:Takasugi Takayuki and Yoshida Mitsuhiko
[TITL]:Microstructure and High Temperature Deformation of In-situ
NbCr[2]-based Intermetallic Composite
[SOUR]:THERMEC'97: Proc. Int. Conf. Thermomechanical Processing of Steels &
Other Materials, ed. by T. Chandra and T. Sakai, (1997), 1295-1301
[LAB ]:(1); Hanada; Miyagi National College of Technol.
[ABST]:The phase relation and microstructure of the ternary Nb-Cr-X alloy
systems are firstly characterized. A variety of duplex microstructures
consisting of the C15 NbCr[2] Laves phase and bcc solid solution are
formed depending on alloy system and alloy composition. High
temperature deformation of these in-situ NbCr[2] based intermetallic
composites prepared by arcmelting is observed in terms of
microstructural and compositional effect by compression test and TEM.
The observed yield stress and stress-strain curve are largely dependent
on the equilibrating bcc phase (or the NbCr[2] Laves phase), their
volume fraction and morphology, and temperature. Among the observed
alloys, the Nb-Cr-Mo alloy consisting of the C15 NbCr[2] Laves phase
and Nb-rich bcc phase shows a better high temperature mechanical
property; the increased yield stress and largely decreased
brittle-ductile transition temperature (BDTT) was observed.
[TYPE]:Intermetallic Compounds
[PROP]:NbCr[2], laves alloy, high temperature deformation
******************************************************************************
[ID ]:KL97-032
[AUTH]:Takasugi Takayuki, Emori Hiroshi and Hiraga Kenji
[TITL]:High-Resolution Electron Microscopy of Grain Boundaries in
Ni[3](Al[0.8]Ti[0.2]) Bicrystals II. Coincidence Site Lattice
Boundaries
[SOUR]:Philos. Mag. A, 75[5] (1997), 1417-1434
[LAB ]:(2); Hanada; Hiraga
[ABST]:The grain-boundary structure of Sigma=5, [001](36.8K), Sigma=25,
[001](16.26K) and Sigma=3, [011](109.47K) coincidence site lattice
(CSL) tilt boundaries in the Li[2]Ni[3] (Al[0.8]Ti[0.2]) bicrystals
prepared by hot pressing were investigated by high-resolution
transmission electron microscopy with the help of image simulation. An
atomic arrangement in the Sigma=5, [001](36.8K) boundary is asymmetric
with a small quantity of rigid-body translation; accommodation of atoms
is small and is localized on a near-grain-boundary plane. An atomic
arrangement in the Sigma=25. [001](16.26K) boundary is asymmetric
without appreciable rigid-body translation; some atoms are withdrawn
and it is interpreted as an array of dissociated (a/2)[110]
superpartials. An atomic arrangement in the Sigma=3, [011](109.47K)
boundary is primarily symmetric, and local accommodation of atoms and
rigid body translation vary with deviation from the grain-boundary
plane. In the three CSL boundaries observed in this study, atomic-size
cavities are commonly observed.
[TYPE]:Intermetallic Compounds
[PROP]:Ni[3](Al,Ti) alloy, grain boundary structure, high resolution electron
microscopy, CSL boundary
******************************************************************************
[ID ]:KL97-033
[AUTH]:Takasugi Takayuki, Kimura Akihiko, Sugimoto Takayuki, Saitoh Hideyuki
and Misawa Toshihira
[TITL]:Hydrogen Property in Lattice Associated with the Embrittlement of
Co[3]Ti Alloys
[SOUR]:Intermetallics, 5[6] (1997), 443-448
[LAB ]:(1); Hanada; Matsui; Dept. of Mater. Sci. and Eng., Muroran Inst. of
Technol.
[ABST]:Some observations relating to solubility, diffusion and trap site of
hydrogen were performed on Co[3]Ti alloys in association with their
embrittlement. Hydrogen diffusivity at room temperature was evaluated
to be low, similar to that of pure Ni. The desorption curve of hydrogen
reached the maximum at sim430K and the corresponding activation energy
was estimated to be 48 kJ mol]-1[. The fracture energy of the
hydrogen-precharged Co[3]Ti alloys measured by a small punch (SP) test
was dependent on the hydrogen content and the alloy stoichiometry; it
decreases with increasing hydrogen content and Ti content. It is
suggested that the environmental embrittlement of the Co[3]Ti alloy
requires the hydrogen transport mode not via lattice diffusion. Also,
the difference in the environmental embrittlement between the two
tested alloy compositions is primarily due to the difference in the
critical hydrogen content causing grain boundary fracture (i.e.
intrinsic grain boundary cohesion).
[TYPE]:Intermetallic Compounds
[PROP]:Co[3]Ti, L1[2] structure, hydrogen, diffusion
******************************************************************************
[ID ]:KL97-034
[AUTH]:Wang Jie, Zhu Ziqiang, Park Ki Tae, Hiraga Kenji and Yao Takafumi
[TITL]:Low-Temperature Growth of GaN Films on GaAs(100) Substrates by Hot
Plasma Chemical Vapor Deposition
[SOUR]:J. Cryst. Growth, 177[3-4] (1997), 181-184
[LAB ]:(2); Yao; Hiraga
[ABST]:This work presents low-temperature growth of GaN films on GaAs(100)
substrates by radio frequency nitrogen hot plasma with power up to 5
kW. This nitrogen hot plasma provides abundant nitrogen atoms as
nitrogen source for growth of GaN films which results in a growth rate
as high as 4mum/h. In addition, for the first time, GaN films can be
grown at room temperature by using only triethylgallium as Ga source,
in which triethylgallium is effectively dissociated by the strong
vacuum ultraviolet emissions from the hot plasma. Low-temperature
photoluminescence (18K) of the sample grown at room temperature shows
strong blue emission with broad region from 3.5 to 2.1 eV and main
emission peak at 2.997 eV. X-ray diffraction and transmission electron
microscopy results show that GaN films grown at low-temperature have a
mixed structure of cubic, hexagonal and amorphous phases; however, GaN
films grown at 600Ž have mainly a cubic structure.
[TYPE]:Intermetallic Compounds
[PROP]:hot plasma CVD, GaN, GaN/GaAs epitaxy
******************************************************************************
[ID ]:KL97-035
[AUTH]:Yoshida Mitsuhiko and Takasugi Takayuki
[TITL]:Phase Relation and Microstructure of Nb-Cr-V and Nb-Cr-Mo Alloy Systems
[SOUR]:Mater. Sci. Eng., A224 (1997), 69-76
[LAB ]:(1); Miyagi National College of Technol.; Hanada
[ABST]:The phase diagrams of ternary Nb-Cr-V and Nb-Cr-Mo alloy systems at
1623 K are investigated by metallography, X-ray diffraction (XRD) and
transmission electron microscopy (TEM) equipped with energy-dispersive
X-ray (EDX) analysis. In both alloy systems, the C15 NbCr[2] Laves
phases are equilibrated directly with b.c.c phase without forming any
intermediate phases. The C15 NbCr[2] Laves phase accommodates a
relatively large amount of ternary elements V and Mo, and extends along
directions so that V and Mo occupy sites of the component elements Cr
and Nb, respectively. The b.c.c phase has a larger solid solution range
in the V (or Mo)-rich side than in the Nb- and Cr-rich sides. A variety
of duplex microstructures are observed depending on the alloy system
and alloy composition. Also, it is shown by TEM that the constituent
C15 phase containing V consists of featureless microstructure while
that containing Mo involves the metastable C36 phase in addition to
microtwins and stacking faults in the C15 phase.
[TYPE]:Intermetallic Compounds
[PROP]:Nb-Cr-V alloy, Nb-Cr-Mo alloy, Laves alloy, phase relation,
microstructure
******************************************************************************
[ID ]:KL97-036
[AUTH]:Yoshida Mitsuhiko and Takasugi Takayuki
[TITL]:Phase Relation and Microstructure of NbCr[2] Laves Intermetallics in
Ternary Nb-Cr-X Alloy Systems
[SOUR]:Mater. Res. Soc. Symp. Proc., 460 (1997), 659-664
[LAB ]:(1); Miyagi National College of Technol.; Hanada
[ABST]:The isothermal phase diagrams of ternary alloy systems Nb-Cr-V and
Nb-Cr-Mo are determined by metallography, X-ray diffraction (XRD) and
transmission electron microscopy (TEM) equipped with energy dispersive
X-ray (EDX). In two alloy systems, the C15 NbCr[2] Laves phases are
equilibrated directly with bcc solid without forming any intermediate
phases. Relatively large amount of ternary elements V and Mo are
soluble in the C15 NbCr[2] Laves phases. It is shown that the C15 Laves
phases extend along directions so that V occupies Cr site while Mo
occupies Nb site. Also, characteristic structure containing micro twins
and stacking faults is observed in the C15 Laves phase alloyed with Mo.
Bcc phase has a wider solid solution range in the X(=V and Mo)-rich
side than the Nb-rich and Cr-rich sides. A variety of duplex
microstructures are observed depending on alloy composition.
[TYPE]:Intermetallic Compounds
[PROP]:Nb-Cr alloy, NbCr[2] laves alloy, phase relation, microstructure
******************************************************************************
[ID ]:KL97-037
[AUTH]:Semboshi Satoshi, Hosoda Hideki and Hanada Shuji
[TITL]:Effects of Second Phases on the Pulverization of Nb[3]Al-Base Alloys by
Hydrogenation (in Japanese)
[SOUR]:Nippon Kinzoku Gakkaishi (J. Jpn. Inst. Met.), 61[10] (1997), 1132-1138
[LAB ]:(3); Hanada
[ABST]:Some Nb[3]Al-base alloys are known to be pulverized by holding in
hydrogen atmosphere. The pulverization by hydrogenation is expected to
be applied to preparation of fine powder with high quality and low
cost. The purpose of this study is to investigate the mechanism of
pulverization by hydrogenation of Nb[3]Al-base alloys with or without
second phases. Alloys prepared were Nb[3]Al single phase alloy (Nb-21
mol%Al alloy: Nb-21Al), and two phase alloys including Nb solid
solution (Nb-16 mol%Al alloy: Nb-16Al) and Nb[2]Al (Nb-28 mol% Al
alloy: Nb-28Al). They were heat-treated at 1473 K for 86.4 ks in a
vacuum atmosphere. After surface treatment, hydrogenation was carried
out under hydrogen pressure from 0 to 3.4 MPa at 313 K and 353K. Powder
formed by hydrogenation was observed using a scanning electron
microscope. Identification of phases and measurement of lattice
constants before and after hydrogenation were carried out by X-ray
diffraction. It is clearly seen that both the two phase alloys, Nb-16Al
and Nb-28Al, are pulverized by hydrogenation. On the other hand, the
single phase alloy, Nb-21Al, is not pulverized under the experimental
conditions. Then, it is assumed that the existence of the second phases
accelerates the pulverization by hydrogenation. Both lattice constants
and volumes increase remarkably through hydrogenation and no hydric
compound is recognized. It is concluded that the pulverization of
Nb-16Al and Nb-28Al is caused by large strain energy generated by the
difference in lattice expansions between Nb[3]Al and Nb solid solution,
and between Nb[3]Al and Nb[2]Al in pulverization by hydrogenation. In
the case of single phase alloy of Nb-21Al, little strain energy is
generated through hydrogen absorption, that leads to difficulty in
pulverization under the experimental conditions.
[TYPE]:Intermetallic Compounds
[PROP]:Nb[3]Al, niobium solid solution, Nb[2]Al, hydrogenation, pulverization,
second phase
******************************************************************************
[ID ]:KL97-038
[AUTH]:Arai Kenta, Zhu Zi Qiang, Sekiguchi Takashi, Yasuda Takashi, Lu Fang,
Segawa Yuusaburo, Kuroda Noritaka and Yao Takafumi
[TITL]:Micro-Cathodoluminescence Study of ZnSe Quantum Dots Embedded in ZnS
Grown by Molecular Beam Epitaxy
[SOUR]:Nonlinear Opt., 18[2-4] (1997), 307-310
[LAB ]:(2); Yao; Suezawa; Photodynamics Res. Center, RIKEN
[ABST]:ZnSe quantum dots embedded in ZnS were fabricated by molecular beam
epitaxy on GaP(001) substrates. During the deposition of Zn and Se,
both the Zn deposition time and substrate temperature were used to
control deposition. The micro-cathodoluminescence images of the ZnSe
quantum dots show a spatial dependence, which reflects the existence of
quantum dots. The cathodoluminescence emission from the ZnSe quantum
dots is observed even at 300 K, demonstrating the strong quantum
confinement of the quantum dots.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe/ZnS quantum dots, MBE, CL
******************************************************************************
[ID ]:KL97-039
[AUTH]:Bagnall Darren M.
[TITL]:High Temperature Stimulated Emission of ZnO Grown by Plasma Assisited
Molecular Beam Epitaxy
[SOUR]:Nonlinear Opt., 18[2-4] (1997), 243-246
[LAB ]:(2); Yao; Dept. of Phys., Tohoku Univ.
[ABST]:ZnO grown by plasma enhanced molecular beam epitaxy on (0001) sapphire
substrates was found to consist of a 300nm epitaxial layer with quantum
sized pyramids on the surface. Room temperature simulated emission was
observed from these samples with a threshold intensity of 300 kWcm]-2[.
Stimulated emission was observed at 500K and T[0] is found to be around
90K in the range 300K to 500K.
[TYPE]:Semimetals and Semiconductors
[PROP]:stimulated emission, ZnO, MBE
******************************************************************************
[ID ]:KL97-040
[AUTH]:Bakhtizin Raouf Z., Park Chan H.
[TITL]:Scanning Tunneling Microscopy Study of Lithium Adsorption on the
Si(111) Surface
[SOUR]:Phys. Low-Dim. Struct., 3/4 (1997), 39-48
[LAB ]:(2); Bashkir State Univ.; Dept. of Phys., Jeonbug National Univ. South
Korea; Hitachi Ltd.; Sakurai
[ABST]:Field ion-scanning tunneling microscopy and low-energy electron
diffraction have been employed to study the geometry and
coverage-dependent growth structures formed by lithium deposition on a
clean Si(111) surface at room temperature. The 3 times 1 reconstruction
of the Si(111)-7 times 7 surface is observed at submonolayer Li
coverage and post-deposition anneal. Our data showed that there is a
threshold depending on coverage and annealing temperature for the 3
times 1 structure formation process. However, there was no evidence of
any sqrt3 times sqrt3 reconstruction of the Si(111) surface induced by
lithium adsorption under the experimental conditions we used. By
comparing the number of Li adatoms on the definite area of the Si(111)
surface after the deposition and annealing at 400Ž it has been proven
that the 3 times 1 islands do not consist of Si atoms only.
[TYPE]:Semimetals and Semiconductors
[PROP]:STM, Si(111), adsorption
******************************************************************************
[ID ]:KL97-041
[AUTH]:Bakhtizin Raouf Z.
[TITL]:Atomic Structures of Gallium-Rich GaAs(001)-4 times 2 and GaAs(001)-4
times 6 Surfaces
[SOUR]:J. Exp. Theor. Phys., 84[5] (1997), 1016-1021
[LAB ]:(2); Bashkir State Unive.; Sakurai; Hitachi Ltd.;
[ABST]:Scanning tunneling microscopy is applied for the first time to an
atomic-resolution investigation of the 4 times 2 and 4 times 6 phases
on a gallium-rich GaAs(001) surface obtained by molecular-beam epitaxy
and migration-enhanced epitaxy. A unified structural model is proposed
with consideration of the results of experiments and first-principles
calculations of the total energy. In this model the 4 times 2 phase
consists of two Ga dimmers in the top layer and a Ga dimers in the
third layer, and the 4 times 6 phase is matched to periodically
arranged Ga clusters at the corners of a 4 times 6 unit cell on top of
the 4 times 2 phase.
[TYPE]:Semimetals and Semiconductors
[PROP]:STM, GaAs(100), adsorption
******************************************************************************
[ID ]:KL97-042
[AUTH]:Chen Yefan, Bagnall Darren M.
[TITL]:Observation of Zinc Oxide Quantum Pyramids Grown by Plasma Enhanced
Molecular Beam Epitaxy
[SOUR]:Nonlinear Opt., 18[2-4] (1997), 107-110
[LAB ]:(2); Yao; Suezawa; Hiraga
[ABST]:ZnO quantum pyramids have been grown by plasma enhanced molecular beam
epitaxy on a ZnO buffer layer pre-grown on (0001) sapphire substrate.
These pyramids with well-defined facets appear to have uniform size of
height around 25nm. Monochromatic cathode luminescence images reveal
strong near band gap emission from the quantum pyramids when compare to
the buffer layer underneath. Room temperature stimulated emission was
obtained from these samples.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnO quantum pyramids, quantum structures, MBE
******************************************************************************
[ID ]:KL97-043
[AUTH]:Chiba Toshinobu, Hasegawa Masayuki, Tang Zheng, Akahane Takashi, Manuel
Alfred A
[TITL]:Positron 2D-ACAR Study on Diamonds: Perfect Crystals and Defects
[SOUR]:Mater. Sci. Forum, 255-257 (1997), 521-523
[LAB ]:(1); National Inst. for Res. in Inorganic Mater.; Hasegawa; Univ. of
Geneve; NEC; Sumitomo Electric Indust. Ltd.
[ABST]:We have measured 2D-ACAR of positrons in several kinds of diamond
crystals, namely, natural crystals of types Ia, IIa and synthetic
crystals of types IIa and Ib. Among them we found the synthetic
Sumitomo IIa crystal showed no indication of positron trapping at
temperatures from 295K to 15K. All the crystals showed nearly the same
anisotropies but with different amplitudes, which reflect the covalent
character of the bulk electronic states and were reproduced by the
first principles two-component density functional calculations. We then
irradiated the synthetic Sumitomo crystals by 28MeV electrons (5 times
10]18[e/cm]2[) to introduce mainly monovacancis. The 2D-ACAR
measurements on these crystals revealed the trapping of positrons. The
momentum density contribution from the trapped positrons in
monovacancies were extracted by subtracting the bulk contributions,
which is almost isotropic and reproduced very well by the first
principles calculations. The defect contributions of various types of
diamonds were compared with the above monovacancy component.
[TYPE]:Semimetals and Semiconductors
[PROP]:positron annihilation, 2D-ACAR, diamond, semiconductor, defect
******************************************************************************
[ID ]:KL97-044
[AUTH]:Fu Rong Tang, Esfarjani Keivan, Hashi Yuichi, Wu Jian, Sun Xun and
Kawazoe Yoshiyuki
[TITL]:Surface Reconstruction of Si(001) by Genetic Algorithm and Simulated
Annealing Method
[SOUR]:Sci. Rep. RITU, A44[1] (1997), 77-81
[LAB ]:(2); Dept. of Phys., Fudan Univ.; Kawazoe; Res. and Development Center,
Hitachi Tohoku Software; Dept. of Phys., Tsinghua Univ.
[ABST]:The Genetic Algorithm (GA) is one of the most recently developed
techniques to find the "Global" minimum of an energy functional. This
technique combined with conjugated gradient or molecular dynamics has
been demonstrated to be efficient for the ground-state configuration
search in materials research, e.g. fullerene formation. In this paper,
based on the generalized tight-binding molecular dynamics, we apply the
GA to study the surface reconstruction of Silicon (001) for the first
time. Up to 65 generations, the "Global" minimum or the ground-state
configuration for the surface reconstruction of Si (001) was detected
efficiently in our GA simulation. In our tight-binding model, a perfect
symmetry-dimer structure could coexist in the lists of candidate
structures due to the thermal defect or change transfer which was
described with the smearing parameter empirically. We also perform the
more traditional Simulated Annealing (SA) technique to deal with the
same problem. The results in terms of efficiency, accuracy of the
ground-state reconstructed surface and CPU time are compared.
[TYPE]:Semimetals and Semiconductors
[PROP]:Si(001), molecular dynamics, tight-binding, ground state configuration
******************************************************************************
[ID ]:KL97-045
[AUTH]:Hasegawa Masayuki, Tang Zheng, Chiba Toshinobu, Saito Mineo, Kawasuso
Atsuo, Akahane Takashi, Li Zhi Qiang, Kawazoe Yoshiyuki and Yamaguchi
Sadae
[TITL]:Positron 2D-ACAR Study of Divacancies in Si: Experiments and Theory
[SOUR]:Mater. Sci. Forum, 255-257 (1997), 414-416
[LAB ]:(3); Hasegawa; National Inst. for Res. in Inorganic Mater.; NEC
Informatec System, Ltd.; Sumino; Kawazoe; Yamasada
[ABST]:Two-dimensional angular correlation of annihilation (2D-ACAR) for
divacancies in Si with definite charge states (V[2]]0[, V[2]]1-[ and
V[2]]2-[) are studied theoretically and studied theoretically and
experimentally. The 2D-ACAR for the various charge states shows almost
isotropic and very close to each other. However, using a specimen with
aligned divacansies (V[2]]1-[), we have obtained a small but definite
anisotropy in the 2D-ACAR. All these features are well reproduced by
first principles calculations based on the two-component
density-functional theory. Furthermore calculated anisotropies for the
different charge states show systematic changes arising from the
bonding character of the divacancy electrons. Theoretical 2D-ACAR is
also presented for monovacancies. The present calculation and
experiment demonstrate that the 2D-ACAR is an effective tool to provide
microscopic information about vacancy-type defects.
[TYPE]:Semimetals and Semiconductors
[PROP]:positron annihilation, 2D-ACAR, Si, first-principles calculation,
divacancies
******************************************************************************
[ID ]:KL97-046
[AUTH]:Hayashi Kazushi, Sekiguchi Takashi and Okushi Hideyo
[TITL]:Formation and Relaxation of Hydrogen-Related Defects in the Subsurface
Region of Diamond Films
[SOUR]:Mater. Sci. Forum, 258-263 (1997), 745-750
[LAB ]:(1); Kobe Steel Ltd.; Suezawa
[ABST]:We report the metastability of hydrogen-related defects in
hydrogen-plasma-treated diamond films. In the cathodoluminescence
spectra, a specific broad peak at around 2.3 eV is observed in the
subsurface region of the diamond films treated at 800Ž. The peak is
not observed in those treated below 500Ž; however, it suddenly appears
after low-energy (sim 10 kV) electron beam irradiation. Corresponding
to this phenomenon, the irradiation also leads to a decrease in the
sheet resistance of the films. These results indicate the existence of
a metastable configuration of hydrogen-related defects, which relaxes
by the low-energy electron beam irradiation.
[TYPE]:Semimetals and Semiconductors
[PROP]:hydrogen, diamond films, metastability, cathodoluminescence
******************************************************************************
[ID ]:KL97-047
[AUTH]:Hayashi Kazushi, Yamanaka Sadanori, Watanabe Hideyuki, Sekiguchi
Takashi, Okushi Hideyo and Kajimura Kouji
[TITL]:Investigation of the Effect of Hydrogen on Electrical and Optical
Properties in Chemical-Vapor-Deposited Homoepitaxial Diamond Films
[SOUR]:J. Appl. Phys., 81[2] (1997), 744-753
[LAB ]:(1); Electrotechnical Lab.; Suezawa
[ABST]:We have investigated electrical and optical properties of the
high-conductivity layers formed in both undoped and B-doped diamond
films prepared by chemical vapor deposition. It is found that both
hydrogenated undoped and B-doped diamond films have high-concentration
holes of sim10]18[ cm]-3[ at 297K. These films exhibit little
temperature dependence of the hole concentration between 120 and 400K,
while that oxidized B-doped film has a strong temperature dependence
with an activation energy 0.38 eV. The Hall mobility of all the
hydrogenated films of sim30 cm]2[/Vs at 297 K is one to two orders of
magnitude smaller than of the oxidized B-doped film and increases with
increasing temperature. The I-V characteristics of Al-Schottky contacts
to the hydrogenated undoped film show excellent rectification
properties and the temperature dependence of their forward
characteristics is well explained by a junction theory inclusive of the
tunneling process, i.e., thermionic-field emission theory, indicating
that the depletion layer becomes thin due to high-density space charge
in the depletion layer. We have also found a broad cathodoluminescence
peak at around 540 nm in the hydrogenated films which disappears with
subsequent oxidation treatment, indicating the existence of
hydrogen-related gap states in the subsurface region of as-deposited
homoepitaxial diamond films. High density hydrogen is detected in the
subsurface region of the hydrogenated films by secondary ion mass
spectroscopy. These experimental results suggest the existence of
hydrogen-induced shallow acceptors in the surface region of
as-deposited (hydrogenated) diamond films and that the difference
between the hydrogenated and the oxidized films observed in both
electrical and optical properties originates from hydrogen incorporated
in the subsurface region.
[TYPE]:Semimetals and Semiconductors
[PROP]:diamond, homoepitaxial, H, CL, hall effect, H-related luminescence
******************************************************************************
[ID ]:KL97-048
[AUTH]:Heimbrodt Wolfram, Orange Catherine L., Wolverson Daniel, Davies J.
[TITL]:Determination of Nitrogen-Acceptor Spin-Hamiltonian Parameters in ZnSe
Epilayers via Spin-Flip Raman Spectroscopy
[SOUR]:Phys. Rev. B, 56[11] (1997), 6889-6894
[LAB ]:(2); Univ. of East Anglia; Joint Res. Center for Atom Technol.; Yao
[ABST]:Resonant spin-flip Raman scattering measurements were performed for
nitrogen-doped ZnSe grown on a (001) GaAs substrate by molecular-beam
epitaxy. By tuning the excitation laser to resonance with the
acceptor-bound exciton transition, spin-flip Raman scattering was
observed between the spin states of the neutral nitrogen acceptors
split by an external magnetic field. The spin-flip transitions
exhibited strong magneto-optical anisotropy depending on the
orientation of the magnetic field B with respect to the growth axis.
The strain-induced splitting Delta between the light- and heavy-hole
states was found to play an important role in the interpretation of the
spin-flip Raman spectra. Specimens in which Delta is comparable to the
Zeeman energies of the acceptor were chosen for study. In such
specimens the parameters kappa and q in the spin-Hamiltonian terms
-kappa mu[B] J cdot B and -q mu[B] J]3[ cdot B for the nitrogen
acceptor, together with Delta itself, could be determined accurately by
varying the field direction from [001] to [110] and, in the layer
plane, from [110] via [010] to [110]. The experiments give kappa= -0.50
pm 0.05 and q= -0.005 pm 0.01 and also demonstrate that accurate
determination of the strain splitting Delta is possible for layers in
which Delta is too small for the excitonic transitions involving the
light- and heavy-hole states to be resolved by photoluminescence or by
photoluminescence-excitation spectroscopy.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe, spin-flip Raman spectroscopy, spin-Hamiltonian
******************************************************************************
[ID ]:KL97-049
[AUTH]:Jiang Zui Min, Zhu Hai Jun, Lu Fang, Huang Da Ming, Wang Xun, Chen Ye
Fan, Zhu Zi Qiang and Yao Takafumi
[TITL]:A Silicon-Based Low Dimensional Quantum Structure--- Self-Assembly
Grown Germanium Quantum Dots
[SOUR]:Nonlinear Opt., 18[2-4] (1997), 153-160
[LAB ]:(2); Fudan Univ.; Yao
[ABST]:The growth of Ge islands with fairly uniform size distribution on
Si(100) has been achieved by using MBE under proper growth conditions.
The atomic force microscopy and the cross sectional transmission
electron microscopic observations illustrate that the size and height
uniformities of the islands are not worse than 6%. The Raman scattering
measurements show that the wetting layer is converted into a SiGe alloy
layer due to the intermixing of the overlayer with the substrate during
the growth. The phonon confinement in the Ge dots induces a peak
downward shift of Ge-Ge mode in Raman spectrum. A very narrow peak with
the FWHM of 1.6 meV at the energy of 0.767 eV is observed at the
temperature of 16K. We attribute this peak to the free exciton LA
phonon replica originated from the Ge islands.
[TYPE]:Semimetals and Semiconductors
[PROP]:Ge quantumdots, self-assembly process, quantum structures
******************************************************************************
[ID ]:KL97-050
[AUTH]:Jin Cheng Guo, Yasuda Tetsuji, Kimura Kozo, Ohtake Akihiro, Kuo Li
Hsin, Wang Tai Hong, Miwa Shiro, Yao Takafumi and Tanaka Kazunobu
[TITL]:Non-Contact and Non-Destructive Measurement of Carrier Concentration of
Nitrogen-Doped ZnSe by Reflectance Difference Spectroscopy
[SOUR]:Jpn. J. Appl. Phys., 36[11] (1997), 6638-6644
[LAB ]:(2); Joint Res. Center for Atom Technol.; Yao; Univ. of Tsukuba
[ABST]:We report an optical technique to determine the net carrier
concentration of nitrogen-doped ZnSe, N[a] - N[d]. An optical
anisotropy induced by the built-in field was measured by reflectance
difference spectroscopy (RDS). It has been shown that the energy
derivative of the RD signal near 5 eV is proportional to (N[a]
-N[d])]1/3[ when N[a] - N[d] ] 5 times 10]16[ cm]-3[. The physical
origin of the observed power law is discussed. We also address the
origin of the surface roughness induced baseline in the RD spectra
which affects the accuracy of the measurement.
[TYPE]:Semimetals and Semiconductors
[PROP]:N-doped ZnSe, RDS, Pockels effect
******************************************************************************
[ID ]:KL97-051
[AUTH]:Jung H.D, Song C.D, Wang S.Q, Arai Kenta, Wu Y.
[TITL]:Carrier Concentration Enhancement of p-Type ZnSe and ZnS by Codoping
with Active Nitrogen and Tellurium by Using a delta-Doping Technique
[SOUR]:Appl. Phys. Lett., 70[9] (1997), 1143-1145
[LAB ]:(2); Yao; Fundamental Mater. Res. Center., Samsung Display Devices Co.,
Ltd.; Dept. of Electrical Eng. National Univ. of Singapore; Joint Res.
Center for Atom Technol., National Inst. for Adv. Interdisciplinary
Res.; Dept. of Condensed Matter Phys.,
[ABST]:We have studied the p-type doping of ZnSe and ZnS grown by molecular
beam epitaxy using active nitrogen and tellurium. Highly conductive
p-type ZnSe and ZnS films have been achieved by inserting heavily
N-doped ZnTe layers into each layer. A hole concentration of 7 times
10]18[ cm]-3[ in a ZnSe/Zn Te:N delta-doped layer and a [N[a] - N[d]]
value of 5 times 10]17[ cm]-3[ in a ZnS/ZnTe:N delta-doped layer were
obtained. Excitonic emission associated with the N acceptor at 2.792eV
in ZnSe was dominant in the photoluminescence spectra at 14 K and the
emission related to the Te isoelectronic deep centers was negligibly
weak. These results indicate that the incorporation of ZnTe:N single
layers by this delta-doping method dramatically increases the hole
concentration, and the optical properties are consistent with this
improvement.
[TYPE]:Semimetals and Semiconductors
[PROP]:p-type doping, ZnSe, ZnS, codoping
******************************************************************************
[ID ]:KL97-052
[AUTH]:Jung Hyun Don, Kumagai Naoto, Hanada Takashi, Zhu Zi Qiang, Yao
Takafumi, Yasuda Tetsuji and Kimura Kozo
[TITL]:In situ Reflectance Difference Spectroscopy and Reflection High-Energy
Electron Diffraction Observation of Nitridation Processes on GaAs(001)
Surfaces
[SOUR]:J. Appl. Phys., 82[9] (1997), 4684-4686
[LAB ]:(2); Yao; Joint Res. Center for Atom Technol.
[ABST]:Nitridation processes on GaAs(001) surfaces exposed to N[2] microwave
plasma were investigated by in situ reflectance- difference
spectroscopy, reflection high-energy electron diffraction, and in-line
Auger electron spectroscopy. We have found that a stable GaN layer is
formed only when the As background pressure is sufficiently low.
Nitridation is significantly suppressed under a high background
pressure of As. A possible mechanism and its implication to GaN growth
on GaAs surfaces are discussed.
[TYPE]:Semimetals and Semiconductors
[PROP]:nitridation of GaAs, RDS, RHEED
******************************************************************************
[ID ]:KL97-053
[AUTH]:Kang Yan Sheng, Noda Yasutoshi, Chen Li Dong, Kisara Katsuto and Niino
Masayuki
[TITL]:p-n Joining of Melt-Grown and Sintered PbTe by Plasma Activated
Sintering
[SOUR]:Functionally Graded Materials, ed. by I. Shiota and Y. Miyamoto,
Tsukuba, 1996, (1997), 587-592
[LAB ]:(2); National Aerospace Lab., Kakuda Res Center; Faculty of Eng.,
Tohoku Univ.; Hirai
[ABST]:A p-n junction of PbTe thermoelectric material was prepared by
plasma-activated sintering (PAS) in order to investigate the junction
interface of a stepwise carrier concentration FGM. The component
materials were undoped p-type and 2000 or 4000 molppm PbI[2]-doped
n-type, respectively. The n-type component was made from a mixture of
PbTe and PbI[2] powder or a powder which was obtained by grinding a
PbI[2] doped melt-growth crystal. The microscopic observation was
carried out for the component materials, which indicated the grain
growth during PAS. The electric properties were almost consistent with
those for the single crystals. The characterization of the p-n junction
was carried out by measuring thermoelectromotive force, voltage profile
and current(I)-voltage(V) relationship across the joint boundary. An
abrupt change of conduction type for the termoelectromotive force and a
continuous distribution for the voltage were observed at the joint
boundary. The voltage profile was different from that of the stepwise
FGMs of SiGe and PbTe with abrupt change at the joint boundary. The I-V
relationship in forward and reverse direction bias differs each other
which was limited in low voltage region. These results indicate that
the junction was successfully performed by the PAS process.
[TYPE]:Semimetals and Semiconductors
[PROP]:PbTe, p-n joining, thermoelectric
******************************************************************************
[ID ]:KL97-054
[AUTH]:Kawasuso Atsuo, Okada Sohei, Suezawa Masashi, Honda Tatsuya and
Yonenaga Ichiro
[TITL]:Positron Annihilation in Electron-Irradiated Si[x]Ge[1-x] Bulk Crystals
[SOUR]:J. Appl. Phys., 81[6] (1997), 2916-2918
[LAB ]:(2); Japan Atomic Energy, Res. Inst.; Suezawa
[ABST]:Position lifetime measurement for Si[x]Ge[1-x] bulk crystals has been
performed. The bulk lifetime of positron in the crystals varied between
those for Ge and Si. The dependence of the lifetime on the alloy
composition showed an abrupt change at x=0.17-0.20 which seems to be
correlated with that of the band gap energy. After 3MeV
electron-irradiation, vacancy-type defects giving rise to the lifetimes
of sim280 and sim330 ps were detected for 0.63 leqslant x leqslant 0.82
and 0.20 leqslant x leqslant 0.40, respectively, but not for x leqslant
0.17. The composition-dependent vacancy production was interpreted in
terms of the thermal stability of vacancies with the composition.
[TYPE]:Semimetals and Semiconductors
[PROP]:Si, Ge, alloy, electron-irradiation, positron annihilation
******************************************************************************
[ID ]:KL97-055
[AUTH]:Kimura Kouzou, Miwa Shirou, Yasuda Tetsuji, Kuo Li Hsin, Jin Cheng Guo,
Tanaka Kazunori and Yao Takafumi
[TITL]:Efficient Doping of Nitrogen with High Activation Ratio into ZnSe Using
a High-Power Plasma Source
[SOUR]:Appl. Phys. Lett., 70 (1997), 81-83
[LAB ]:(2); Sumitomo Electric Industry, Ltd.; Sony Corp.; National Inst. for
Advanced Interdisciplinary Res.; Angstrom Technol. Partnership; Univ.
of Tsukuba; Yao
[ABST]:We have developed a high-powder (5 kW) rf plasma source for nitrogen
doping in ZnSe molecular beam epitaxy. Optical emission spectroscopy
shows dominant atomiclike emissions around 800nm due to excited neutral
nitrogen atoms in the high powder region and their intensities rapidly
increase with increasing the rf power from 1 to 3 kW. The high net
acceptor concentration (N[A]-N[D]) of 1.2 times 10]18[ cm]-3[ was
achieved at the growth temperature of 220Ž and the activation ratio
[(N[A]-N[D])/N] as high as 60%, which is the highest value so far
obtained for N[A]-N[D] sim10]18[ cm]-3[. Consequently, the PL spectrum
showed well-resolved deep donor-acceptor pair emissions even with high
N[A]-N[D].
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe, N doping, plasma doping
******************************************************************************
[ID ]:KL97-056
[AUTH]:Kimura Kozo, Miwa Shiro, Jin Cheng Guo, Kuo Li Hsin, Yasuda Tetsuji,
Ohtake Akihiro, Tanaka Kazunobu, Yao Takafumi and Kobayashi Hitoshi
[TITL]:Atomic Nitrogen Doping in p-ZnSe Molecular Beam Epitaxial Growth with
Almost 100% Activation Ratio
[SOUR]:Appl. Phys. Lett., 71[8] (1997), 1077-1079
[LAB ]:(2); Joint Res. Center for Atom Technol.; Yao; Sony Corp. Res. Center
[ABST]:An almost 100% activation ratio {(N[A]-N[D])/[N]} for a nitrogen-doped
ZnSe molecular beam epitaxy(MBE) layer with the highest net acceptor
concentration (N[A]-N[D]) of 1.2 times 10]18[ cm]-3[ was obtained using
a high-power rf plasma source. Even at this high N[A]-N[D] value, a 4.2
K photoluminescence spectrum shows bound exciton emission and deep
donor-acceptor pair emission with well-resolved phonon replicas. The
high activation in nitrogen doping could be ascribed to the generation
of the predominant atomic nitrogen and to the suppressed extraction of
nitrogen ions and excited neutral nitrogen molecules due to the
structure of the orifice placed between the MBE growth chamber and the
plasma discharge tube of the high-power plasma source.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe, p-type doping, nitrogen doping
******************************************************************************
[ID ]:KL97-057
[AUTH]:Kimura Kozo, Miwa Shiro, Kajiyama Hiroshi, Yasuda Tetsuji, Kuo Li Hsin,
Jin Cheng Guo, Tanaka Kazunobu and Yao Takafumi
[TITL]:The Effect of Nitrogen Ions Emitted from a Plasma Source on Molecular
Beam Epitaxial Growth of p-ZnSe:N
[SOUR]:Appl. Phys. Lett., 71[4] (1997), 485-487
[LAB ]:(2); Joint Res. Center for Atom Technol.; Angstrom Technol. Partnership
(ATP); Adv. Interdisciplinary Res.(NAIR); Univ. of Tsukuba; Sumitomo
Electric Industry, Ltd.; Sony Corp.; Adv. Res. Lab., Hitachi, Ltd.; Yao
[ABST]:Excited neutral nitrogen species emitted from a rf plasma source were
characterized by the laser-induced fluorescence (LIF) spectroscopy,
while nitrogen ions were detected by the ion counting method. The LIF
intensity for nitrogen molecules increases monotonously up to the rf
powder of 100 W and saturates over 100W. On the contrary, ion count of
nitrogen ions shows a gradual increase up to 100W, then rapidly
increases above 100 W. The correlation between the number of excited
nitrogen species and the net acceptor concentration (N[A]-N[D]) of
nitrogen doped ZnSe epitaxial layers for various rf powers has been
studied. We confirm that the excited neutral nitrogen molecules are
effective for acceptor doping, while nitrogen ions enhance carrier
compensation presumably due to degradation of crystal quality. We show
that the activation ratio {(N[A]-N[D])/[N]} of p-ZnSe: N is greatly
improved by removing ions from the nitrogen plasma.
[TYPE]:Semimetals and Semiconductors
[PROP]:p-ZnSe, N doping, N plasma source
******************************************************************************
[ID ]:KL97-058
[AUTH]:Kimura Kozo, Miwa Shiro, Yasuda Tetsuji, Kuo Li Hsin, Ohtake Akihiro,
Jin C.G
[TITL]:Molecular Beam Epitaxial Growth of P-ZnSe:N Using a Novel Plasma Source
[SOUR]:J. Electron. Mater., 26[6] (1997), 705-709
[LAB ]:(2); Joint Res. Center for Atom Technol.; Angstrom Technol.
Partnership; National Inst. for Adv. Interdisciplinary Res.; Univ. of
Tsukuba; Yao
[ABST]:We have studied the p-type doping in ZnSe molecular beam epitaxial
growth using a novel high-power (5 kW) radio frequency (rf) plasma
source. The effect of growth conditions such as the rf power, the Se/Zn
flux ratio and the growth temperature on p-ZnSe:N was investigated. The
net acceptor concentration (N[A]-N[D]) of around 1 times10]18[cm]-3[
was reproducibly achieved. The activation ratio ((N[A]-N[D])/[N]) of
p-ZnSe:N with N[A]-N[D] of 1.2 times 10]18[cm]-3[ was found to be as
high as 60%, which is highest value so far obtained for N[A]-N[D]
sim10]18cm]-3[. The 4.2K photoluminescence spectra of p-ZnSe:N grown
under the optimized growth condition showed well-resolved deep-acceptor
pair emissions even with high N[A]-N[D].
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe, p-type doping, N doping, MBE
******************************************************************************
[ID ]:KL97-059
[AUTH]:Kiyama Hisashi, Xue Qi Kun and Sakurai Toshio
[TITL]:STM Study of MBE Grown III-V Semiconductors
[SOUR]:J. Korean Phys. Soc. (Proc. Suppl.), 31 (1997), S13-S15
[LAB ]:(3); Sakurai
[ABST]:We have investigated novel layer-by-layer MBE growth of highly strained
InAs epilayers on the GaAs(001) substrate up to 13 ML, by in-situ
scanning tunneling microscopy (STM). This growth can be only achieved
when the growing front exhibits a 4 times 2 or a new 6 times 2
diffraction symmetry. Here we will discuss the atomic structure of
these two reconstructions which facilitate novel planar growth, and
also document the relationship between the growth mode and surface
reconstruction.
[TYPE]:Semimetals and Semiconductors
[PROP]:III-V compound semiconductor, MBE, STM
******************************************************************************
[ID ]:KL97-060
[AUTH]:Kobayashi Hitishi, Kimura Kozo, Nishiyama Fumitaka, Miwa Shiro and Yao
Takafumi
[TITL]:Lattice Location of N in ZnSe by Channeling-NRA
[SOUR]:Nucl. Instrum. Methods Phys. Res. B, 132 (1997), 142-146
[LAB ]:(2); Sony Co. Res. Center; Joint Res. Center for Atom Technol.;
Hiroshima Univ.
[ABST]:The lattice location of N in ZnSe has been investigated by nuclear
reaction analysis(NRA) in combination with ion channeling technique.
We have improved the detection limit of N to 1 times 10]17[ atoms/cm]3[
using the nuclear reaction ]15[N(P, alpha)]12[C without significant
crystalline damage. Molecular beam epitaxy (MBE) grown ZnSe this films
implanted with ]15[N ions (dose=1 times 10]14[cm]-2[) were
investigated. It was found that sim35% of N is in the substitutional
sites and that the fraction in the Zn sites and in the Se sites is
almost the same in the as-implanted sample. We have also found that the
lattice location of N was changed by annealing at 500Ž for 60 min and
sim15% of N move to the tetrahedral intersititial sites.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe, N doping, Ion channeling
******************************************************************************
[ID ]:KL97-061
[AUTH]:Kuo L.
[TITL]:Role of Interface Chemistry and Growing Surface Stoichiometry on the
Generation of Stacking Faults in ZnSe/GaAs
[SOUR]:J. Electron. Mater., 26[2] (1997), 53-63
[LAB ]:(2); Joint Res. Center for Atom Technol., Angstrom Technol.
Partnership; National Inst. for Adv. Interdisciplinary Res.; Yao
[ABST]:The existence of Zn-As and vacancy-contained Ga-Se interfacial layers
are suggested by transmission electron microscopy of Zn- and Se-exposed
(or - reacted) ZnSe/GaAs interfaces, respectively. A very low density
of faulted defects in the range of sim10]4[/cm]2[ was obtained in
samples with Zn passivation on an As-stabilized GaAs-(2 times 4).
However, the density of As precipitates increases as the surface
coverage of c(4 times 4) reconstruction increased on the Zn-exposed
As-stabilized GaAs-(2 times 4) surface and this is associated with an
increase of the density of extrinsic-type stacking faults bound by
partial edge dislocations with a core structure terminated on
additional cations. On the other hand, densities of extrinsic
Shockley-and intrinsic Frank-type stacking faults are of sim 5 times
10]7[/cm]2[ in samples grown on Se-exposed Ga-rich GaAs-(4 times 6)
surfaces. Annealing on this Se-exposed Ga-rich GaAs-(4 times 6)
generated a high density of vacancy loops 1 times 10]9[/cm]2[ and an
increase of the densities of both Shockley- and Frank-type stacking
faults (geq 5 times 10]8[/cm]2[) after the growth of the films.
Furthermore, we have studied the dependence of the generation and
structure of Shockley-type stacking faults on the beam flux rations in
samples grown on Zn-exposed As-stabilized GaAs-(2 times 4) surfaces.
Cation- and anion-terminated extrinsic-type partial edge dislocations
were generated in samples grown under Zn- and Se-rich conditions,
respectively. However, an asymmetric distribution on defect density
under varied beam flux ratios (0.3 leq P[Se]/P[Zn] leq 10) is obtained.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe/GaAs, interface, defect generation
******************************************************************************
[ID ]:KL97-062
[AUTH]:Kuo Li Hsin, Kimura Kozo, Miwa Shiro, Yasuda Tetsuji, Ohtake Akihiro
and Yao Takafumi
[TITL]:Dependence of Defect Generation and Structure on Interface Chemistry in
ZnSe/GaAs
[SOUR]:Appl. Surf. Sci., 117/118 (1997), 495-502
[LAB ]:(2); Angstrom Technol. Partnership; Yao
[ABST]:Formation of Zn-As and Ga[2]Se[3]-like interfacial layers are suggested
by transmission electron microscopy in ZnSe films grown on Zn-exposed
GaAs-(2 times 4) and Se-exposed GaAs-(4 times 6) surfaces,
respectively. The densities of As precipitates and extrinsic
Shockley-type stacking faults in the films increase as the surface
coverage of c(4 times 4) reconstruction increased on the Zn-exposed
As-stabilized GaAs surfaces. On the other hand, the densities of
stacking faults in ZnSe/GaAs increase as a function of Se interaction
or contamination on the surfaces of the GaAs epilayers. In these
samples, intrinsic Frank- and extrinsic Shockley-type stacking faults
bound by anion and cation-terminated partial edge dislocations are
generated, respectively.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe/GaAs heterostructure, heterovalency, interface
******************************************************************************
[ID ]:KL97-063
[AUTH]:Kuo Li Hsin, Kimura Kozo, Ohtake Akihiro, Miwa Shiro, Yasuda Tetsuji
and Yao Takafumi
[TITL]:Nature and Origins of Stacking Faults from a ZnSe/GaAs Interface
[SOUR]:J. Vac. Sci. Technol., B, 15[4] (1997), 1241-1253
[LAB ]:(2); Joint Res. Center for Atom Technol.; Yao
[ABST]:Existence of sim3-4 monolayers of Ga[2]Se[3]- and Ga[2]Te[3]-like
interfacial layers are suggested by transmission electron microscopy of
Se- and Te-exposed (or -reacted) ZnSe/GaAs interfaces, respectively.
Densities of extrinsic Shockley- and intrinsic Frank-type stacking
faults are of sim 5 times 10]7[/cm]2[ in samples grown on Se- or
Te-exposed GaAs surfaces. Annealing on the Se- or Te-exposed GaAs
generated a high density of vacancy loops (geqslant 1 times
10]9[/cm]2[) with an increase of the densities of both intrinsic and
extrinsic-type stacking faults (geqslant 5 times 10]8[/cm]2[) after
growth of the films. Formation of the intrinsic stacking faults or
vacancy loops and extrinsic stacking faults may be related to the
presence of cation vacancies and interstitials, respectively, on the
surface of the GaAs epilayer, due to the interaction between Se or Te
and the GaAs epilayer with charge unbalanced Ga-Se or Ga-Te bondings.
On the other hand, sim2 and 3-4 monolayers of Zn-As interfacial layers
are recognized in samples grown on Zn-exposed GaAs-(2 times 4) and -c(4
times 4), respectively. A very low density of fault defects in the
range of sim10]4[/cm]2[ was obtained in samples with Zn treatment on an
As-stabilized GaAs-(2 times 4). However, the density of As precipitates
increases as the surface coverage of c(4 times 4) reconstruction
increased on the Zn-exposed As-stabilized GaAs-(2 times 4) surface and
this is associated with an increase of the density of extrinsic-type
stacking faults bound by partial edge dislocations with a core
structure terminated on additional cations. Clustering of excess As
atoms and formation of Zn interstitials due to charge unbalance of
Zn-As bondings on the GaAs surface may act as nucleation sites for the
generation of the high densities of As precipitates and extrinsic-type
stacking faults, respectively. These local stacking errors due to
interaction between Zn and GaAs-c(4 times 4) is reduced by thermal
annealing. In this case, thickness of the Zn-As interfacial layer is
decreased with increasing annealing temperature and a very low density
of the fault defects is obtained.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe/GaAs interface, TEM, heterovalency
******************************************************************************
[ID ]:KL97-064
[AUTH]:Kurtz Elisabeth, Jung Hyun Don, Hanada Takashi, Zhu Zi Qiang, Sekiguchi
Takashi and Yao Takafumi
[TITL]:The Growth and Photoluminescence Properties of Self-Organized CdSe
Quantum Dots on a (111)A ZnSe Surface
[SOUR]:Nonlinear Opt., 18[2-4] (1997), 93-98
[LAB ]:(2); Yao; Suezawa
[ABST]:Growth and properties of self-organized CdSe quantum dots (SQDs) grown
by atomic layer epitaxy (ALE) on the atomically flat surface of (111)A
ZnSe buffer layers have been investigated. We observe formation of dots
at nominal layer thicknesses well below the critical thickness of the
CdSe, a strong indication for coherent Stranski-Krastanow islanding.
When the number of ALE cycles is increased the average dot size remains
unchanged, instead the density is increased. Rather uniform base
diameters (47 pm 5 nm) are observed. The morphology of the buffer
layers, dot structures and optical properties of the SQDs will be
discussed.
[TYPE]:Semimetals and Semiconductors
[PROP]:CdSe quantum dots, (111)A ZnSe surface, PL properties,
self-organization
******************************************************************************
[ID ]:KL97-065
[AUTH]:Kusanagi Susumu, Sekiguchi Takashi and Sumino Koji
[TITL]:Electron Beam Induced Current Study on Deformation-induced Dislocations
in Silicon Crystals
[SOUR]:Proc. The Kazusa Akademia Park Forum on the Science and Technology of
Silicon Materials, (1997), 377-382
[LAB ]:(2); SONY Corp.; Suezawa; NIPPON STEEL Corp.
[ABST]:We observed the deformation induced dislocations in silicon by means of
EBIC technique and measure the temperature dependencies of their EBIC
contrasts. These results were analyzed according to Donolto's EBIC
theory and carrier recombination theory. Then we determined the energy
levels of the dislocations.
[TYPE]:Semimetals and Semiconductors
[PROP]:Si, EBIC, dislocation, debris, temperature dependence
******************************************************************************
[ID ]:KL97-066
[AUTH]:Lu Fang, Wang Shouqi, Jung Hyundon, Zhu Ziqiang and Yao Takafumi
[TITL]:Photoinduced Admittance Spectroscopy to Detect the Shallow Electron
Traps in Nitrogen-Doped Highly Compensated ZnSe
[SOUR]:J. Appl. Phys., 81[5] (1997), 2425-2428
[LAB ]:(2); Yao
[ABST]:This article describes a technique to detect shallow levels in highly
compensated ZnSe by photoinduced admittance spectroscopy (PIAS).
Nitrogen doped ZnSe with a Schottky barrier on top has been
investigated, and the photovoltage measurements show that the electric
charge in the depletion layer becomes positive under high intensity
illumination with photon energies larger than the energy gap of ZnSe.
An electron trap with an activation energy of 50meV was obtained form
the PIAS measurement. The accuracy of this technique is confirmed by
reconstruction of the temperature dependence of the capacitance and
conductance by a computer simulation.
[TYPE]:Semimetals and Semiconductors
[PROP]:N-doped ZnSe, shallow electron traps, admittance spectroscopy
******************************************************************************
[ID ]:KL97-067
[AUTH]:Markevich Vladimir Pavrovich, Murin Leonid Ivan, Sekiguchi Takashi and
Suezawa Masashi
[TITL]:Emission and Capture Kinetics for a Hydrogen-Related Negative-U Center
in Silicon : Evidence for Metastable Neutral Charge State
[SOUR]:Mater. Sci. Forum, 258-263 (1997), 217-222
[LAB ]:(2); Suezawa; Inst. of Solid State and Semicond. Phys., Berarus
[ABST]:The results of study of electron emission and capture processes for an
amphoteric (having a donor and an acceptor acceptor levels)
hydrogen-related center with negative-U properties in crystalline
silicon are presented. It is found that only singly negatively and
singly positively charged states of the defect are stable, but for the
description of the transient process between these states
thermodynamically unstable neutral charge state should be taken into
account. Two local energy minima in configurational space are suggested
to be present for this state. A non-equilibrium occupancy statistics
for the negative-U centers with such a electronic structure has been
developed and analytical expression for the time constant of the
occupancy transient process (tau[f]) is obtained. Experimentally
observed tau[f]]-1[(1/T) dependencies were described perfectly by
applying the developed statistics and the values of energy barriers for
the electron capture and emission were determined.
[TYPE]:Semimetals and Semiconductors
[PROP]:silicon, hydrogen-related center, emission, capture, electronic
structure, metastable state
******************************************************************************
[ID ]:KL97-068
[AUTH]:Miwa Shiro, Kimura Kozo, Kuo Li Hsin, Yasuda Tetsuji and Yao Takafumi
[TITL]:Surface Structure of Zn- or Se-Treated GaAs(001) and Its Influence for
ZnSe Heteroepitaxy
[SOUR]:Appl. Surf. Sci., 117/118 (1997), 472-476
[LAB ]:(2); Joint Res. Center for Atom Technol.; Yao
[ABST]:The surface structures of Se- or Zn-treated GaAs(001) have been
investigated using scanning tunneling microscopy, X-ray photoelectron
spectroscopy, and reflection high-energy electron diffraction connected
to a dual chamber MBE system. The influence of controlled GaAs surface
for the initial stage of ZnSe heteroepitaxy has also been studied. A(2
times 1) structure was generated by Se-exposure on both As- and
Ga-stabilized GaAs(001) surface. This is recognized as result of the
reaction between Se and Ga. In the case of Zn-exposure on (2 times 4)
surfaces, the change of RHEED intensity and XPS measurement suggested
Zn deposition but there were no obvious changes in the STM images.
During the ZnSe growth on a Se-terminated GaAs-(2 times 1) surface,
RHEED patterns immediately became spotty and a disordered rough surface
was observed by STM. On the other hand, during ZnSe growth on the
Zn-treated GaAs-(2 times 4) surface, RHEED patterns were streaky from
the very beginning. We could also successfully obtain STM images of a
Se-stabilized ZnSe(001)-(2 times 1) reconstruction and this means that
well-ordered surfaces were obtained as a result of layer mode growth
using the Zn-treatment.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe, surface treated, GaAs, heteroepitaxy
******************************************************************************
[ID ]:KL97-069
[AUTH]:Miwa Shiro, Kimura Kozo, Yasuda Tetsuji, Nomachi Ichiro, Kobayashi
Hajime and Yao Takafumi
[TITL]:Nitrogen Detection in ZnSe and ZnTe
[SOUR]:Secondary Ion Mass Spectrometry: SIMS X: Proc. 10th Int. Conf.
Secondary Ion Mass Spectrometry, Muenster, 1995, (1997), 533-536
[LAB ]:(2); Joint Res. Center for Atom Technol.-(ATP); Joint Res. Center for
Atom Technol.-(NAIR); Sony Co. Res. Center; Yao
[TYPE]:Semimetals and Semiconductors
[PROP]:N doping, ZnSe, ZnTe, SIMS
******************************************************************************
[ID ]:KL97-070
[AUTH]:Miwa Shiro, Kuo Li Hsin, Kimura Kozo, Ohtake Akihiro, Yasuda Tetsuji,
Jin Cheng Guo and Yao Takafumi
[TITL]:ZnSe Epitaxy on a GaAs(110) Surface
[SOUR]:Appl. Phys. Lett., 71[9] (1997), 1192-1194
[LAB ]:(2); Joint Res. Center for Atom Technol.; Yao
[ABST]:ZnSe molecular beam epitaxial growth on GaAs(110) substrates has been
studied using reflection high-energy electron diffraction (RHEED),
atomic force microscopy, and transmission electron microscopy. An
atomically flat and low defect homoepitaxial buffer GaAs(110) was grown
with high V/III ratio (geqslant 150) and at low growth temperature
(sim430Ž). At the beginning of ZnSe growth on a GaAs(110) buffer
epitaxial layer, RHEED oscillation was observed and no facet was seen
on a pseudomorphic ZnSe(110) surface. Low defect ZnSe films (defect
density leqslant10]5[ cm]-2[) were also obtained without the Zn
preexposure process necessary for low defect ZnSe(001) growth.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe/GaAs(110) epitaxy, MBE, defect generation
******************************************************************************
[ID ]:KL97-071
[AUTH]:Miwa Shiro, Kuo Li Hsin, Kimura Kozo, Yasuda Tetsuji and Yao Takafumi
[TITL]:Structural Change of As-Stabilized GaAs(001)-(2 times 4) and -c(4 times
4) Induced by Zinc Exposure
[SOUR]:Jpn. J. Appl. Phys., 36[3B] (1997), L337-L340
[LAB ]:(2); Joint Res. Center for Atom Technol.-Angstrom Technol. Partnership;
Joint Res. Center for Atom Technol.-National Inst. for Adv.
Interdisciplinary Res.; Yao
[ABST]:The surface structures of Zinc-treated As-stabilized GaAs(001)-(2 times
4) and -c(4 times 4) have been studied using reflection high-energy
electron diffraction, in situ scanning tunneling microscopy and
transmission electron microscopy in order to understand the
Zn-pre-exposure process in ZnSe growth on GaAs(001). A weakening of
RHEED patterns of [110] azimuth was observed in Zn-exposed GaAs-(2
times 4) surface. However, no obvious change was shown in STM images.
On the other hand, Zn-exposure on a GaAs-c(4 times 4) surface induced a
(2 times 2) or very weak (1 times 4) surface structure in RHEED
patterns. Protrusions and an As-dimers/missing-dimer structure were
seen in STM images. Moreover, during ZnSe growth the surface
protrusions observed by STM can diffuse into the film and produce As
precipitates that are confirmed by TEM.
[TYPE]:Semimetals and Semiconductors
[PROP]:As-stabilized GaAs surfaces, surface modification
******************************************************************************
[ID ]:KL97-072
[AUTH]:Nam Chan Woo, Ashok S.
[TITL]:Thermal Anneal Activation of Near-Surface Deep Level Defects in
Electron Cyclotron Resonance Hydrogen Plasma-Exposed Silicon
[SOUR]:J. Vac. Sci. Technol., B, 15[2] (1997), 226-231
[LAB ]:(2); The Pennsylvania State Univ.; Suezawa
[ABST]:Electron cyclotron resonance hydrogen plasma has been found effective
in cleaning Si surfaces in a matter of minutes, with no substrate
heating. Deep level transient spectroscopy measurements showed only a
broad defect peak with relatively low concentration immediately after
the plasma exposure. Subsequent thermal anneals reveal emergence of
strong new defects that have apparently been latent until the thermal
anneal treatment. After annealing at temperatures above 450Ž, several
well-defined defect peaks with concentrations above 1 times
10]13[cm]-3[ appear near the Si surface. These defect concentrations
reach their maximum at an anneal temperature of 500Ž and reduce to
negligible levels at 750Ž. Experiments on wafers of different oxygen
concentrations show that these defects are unrelated to presence of
oxygen in Si.
[TYPE]:Semimetals and Semiconductors
[PROP]:Si, PL, DLTS, hydrogen plasma, passivation
******************************************************************************
[ID ]:KL97-073
[AUTH]:Narusawa Tadashi, Nishiyama Fumitaka, Zhu Ziqiang and Yao Takafumi
[TITL]:(110) Substrates for ZnSe on GaAs Heteroepitaxy
[SOUR]:Jpn. J. Appl. Phys., 36 (1997), L12-L14
[LAB ]:(2); Matsushita Res. Inst. Tokyo; Dept. of Appl. Phys. and Chem.,
Hiroshima Univ.; Yao
[ABST]:In this letter we present definitive that the ZnSe epitaxial layer
grows far better on GaAs(110) than on conventional GaAs(100)
substrates. This evidence was derived from channeling measurements of
2MeV He ions along major crystalline directions; the ZnSe on GaAs(100)
system exhibited a large interface disorder peak in channeling
backscattering spectra, whereas the ZnSe on GaAs(110) system gave
smooth and featureless spectra. We deduce the quantitative interface
disorder from the measurements, and discuss a possible correlation
between the interface structure and the charge neutralization problem
of this heteroepitaxial system.
[TYPE]:Semimetals and Semiconductors
[PROP]:Heteroepitaxy, ZnSe, II-VI compounds
******************************************************************************
[ID ]:KL97-074
[AUTH]:Ohtake Akihiro, Kuo Li Hsin, Yasuda Tetsuji, Kimura Kozo, Miwa Shiro,
Yao Takafumi, Nakajima Kaoru and Kimura Kenji
[TITL]:Growth Mode and Defect Generation in ZnSe Heteroepitaxy on
Te-Terminated GaAs(001) Surfaces
[SOUR]:J. Vac. Sci. Technol., B, 15[4] (1997), 1254-1259
[LAB ]:(2); Joint Res. Center for Atom Technol.; Yao; Dept. of Eng. Phys. and
Mechanics, Kyoto Univ.
[ABST]:We have studied growth mode and defect generation in heteroepitaxy of
ZnSe on Te-terminated GaAs(001) surfaces. The high saturation coverage
of Zn on Te-terminated GaAs enhances the layer-by-layer growth of ZnSe.
However, high densities of faulted defects sim5 times 10]8[/cm]2[ are
generated in the ZnSe film. We have found that the generation of
defects is not necessarily ascribed to an island growth mode, but is
closely related to the formation of a vacancy-contained Ga-Te interface
layer.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe, heteroepitaxy, heterovalency
******************************************************************************
[ID ]:KL97-075
[AUTH]:Orihashi Masaki, Noda Yasutoshi, Chen Li Dong, Kang Yan Sheng, Moro
Akio and Hirai Toshio
[TITL]:Preparation of PbTe-FGM by Joining Melt-grown Materials
[SOUR]:Functionally Graded Materials, ed. by I. Shiota and Y. Miyamoto,
Tsukuba, 1996, (1997), 569-573
[LAB ]:(2); Hirai; Faculty of Eng., Tohoku Univ.; National Aerospace Lab.,
Kakuda Res. Center
[ABST]:The 2-stage carrier concentration FGM of PbTe were prepared by plasma
activated sintering(PAS) using the discs cut from melt-grown PbTe
ingots. The component materials of PbTe ingots were prepared by the
Bridgman method after the direct melting of the constituent elements
(Pb and Te) and 2000 or 4000 molppm PbI[2] as a n-type dopant. The PAS
conditions were as follows; in vacuum, pressure of 30 MPa, temperature
at 1050-1100 K, and current of 600 A and voltage of 25 V. The powder of
either of the component materials was adopted as joining reagent of the
discs. The thermoelectric characterization of the FGM was made in the
temperature range from 300 to 700 K. The electrical conductivity of the
FGM at 300 K was almost intermediate between those of the components,
while the thermoelectric powder corresponded to that of the component
with high carrier concentration at high temperature side. The
thermoelectric powder for the FGM was almost intermediate between those
for the components. At T]650 K, the electrical figure of merit for the
FGM was larger than that for the components.
[TYPE]:Semimetals and Semiconductors
[PROP]:PbTe, graded carrier concentration, thermoelectric
******************************************************************************
[ID ]:KL97-076
[AUTH]:Orihashi Masaki, Noda Yasutoshi, Chen Lidong, Kang Yansheng, Moro Akio
and Hirai Toshio
[TITL]:Preparation and Evaluation of PbTe-FGM by Joining Melt-Grown Materials
[SOUR]:Proc. ICT'97: XVI Int. Conf. Thermoelectrics, Germany, (1997), 379-381
[LAB ]:(3); Hirai; Graduate School of Eng., Tohoku Univ.; National Aerospace
Lab., Kakuda Res. Center
[ABST]:The 2-stage functionally graded materials (FGM) of carrier
concentration controlled PbTe were prepared by plasma activated
sintering (PAS) using the discs cut from melt-grown PbTe ingots. The
component materials of PbTe ingots were prepared by the Bridgman
materials of PbTe ingots were prepared by the Bridgman method with 2000
or 4000 molppm PbI[2] as a n-type dopant. The thermoelectric
characterization of the FGM was made in the temperature range from 300
to 700 K. The thermoelectric power (alpha) and the electrical
conductivity (sigma) for the FGM was almost intermediate between those
for the components. In the measured temperature range, the power factor
(alpha]2[ sigma) value for the FGM was found to exceed that for the
components. This results indicate the possibility to realize high
efficiency of energy conversion with the well designed FGM structure.
[TYPE]:Semimetals and Semiconductors
[PROP]:lead telluvide, thermoelectric material, plasma activated sintering,
functionally graded materials
******************************************************************************
[ID ]:KL97-077
[AUTH]:Orihashi Masaki, Noda Yasutoshi, Chen Lidong and Hirai Toshio
[TITL]:Preparation and Thermoelectric Properties of K-Doped p-Type Lead
Telluride
[SOUR]:J. Adv. Sci., 9[1&2] (1997), 32-37
[LAB ]:(2); Hirai; Dept. of Mater. Sci., Faculty of Eng., Tohoku Univ.
[ABST]:Single crystals of K-doped p-type PbTe were prepared by Bridgman
method. The carrier concentration and Hall mobility were measured from
77 to 300K. The hole concentration was successfully controlled in the
range form 8.0 times 10]24[ to 4.0 times 10]25[ m]-3[ with 1000 to
20000 molppm K at 300 K. By calculating kappa[el] on the basis of Fermi
integration, kappa[ph] was estimated to be 2.15 Wm]-1[ K]-1[. By using
the observed thermoelectric power and electrical conductivity value and
the calculated kappa value, figure-of-merits Z of PbTe at 300K were 8.0
times 10]-4[ K]-1[ for p-type at a hole concentration of 1.0 times
10]25[ m]-3[ (2000 molppm K). The mu[H] monotonously decreased with an
increase of carrier concentration. Z remains low due to the low values
of mu[H] and mu[H]/kappa[ph].
[TYPE]:Semimetals and Semiconductors
[PROP]:lead telluride, p-type dopant, thermoelectricity,
figure-of-ment-fermit, fermi integral
******************************************************************************
[ID ]:KL97-078
[AUTH]:Orihashi Masaki, Noda Yasutoshi, Chen Lidong, Kang Yangshen, Moro Akio
and Hirai Toshio
[TITL]:Thermoelectric Properties of Carrier Concentration FGM of PbTe Prepared
by Joining Melt-Grown Materials
[SOUR]:Proc. 14th Int. Japan-Korea Semin. Ceramics, Kanazawa, (1997), 60-63
[LAB ]:(2); Hirai; Graduate School of Eng., Tohoku Univ.; National Aerospace
Lab., Kakuda Res. Center
[ABST]:Lead telluride (PbTe) with graded carrier concentration (called
FGM-PbTe) was prepared by joining melt-grown PbTe discs having
different carrier concentration using plasma activated sintering (PAS).
The component materials of PbTe ingots were prepared by Bridgman method
with 2000 or 4000 molppm PbI[2] as the n-type dopant. In the measured
temperature range 300 to 700 K, the thermoelectric power(alpha) and the
electrical conductivity (sigma) of the FGM was almost intermediate
between those of the components, however, the power factor (alpha]2[
sigma) value of the FGM was found to exceed those of the components.
This results indicate the possibility to realize high efficiency of
energy conversion with the well-designed FGM structure.
[TYPE]:Semimetals and Semiconductors
[PROP]:lead telluride, thermoelectric material, n-type, functionally graded
materials
******************************************************************************
[ID ]:KL97-079
[AUTH]:Saito Mineo, Tang Zheng, Chiba Toshinobu and Hasegawa Masayuki
[TITL]:Theoretical Study on Positron 2D-ACAR for Semiconductors
[SOUR]:Mater. Sci. Forum, 255-257 (1997), 184-188
[LAB ]:(1); NEC Informatec System, Ltd.; Hasegawa; National Inst. for Res. in
Inorganic Mater.
[ABST]:Calculations based on the two-component density functional theory are
performed for positron two-dimensional angular correlation of
annihilation radiation (2D-ACAR), which recently emerged as a powerful
tool to study vacancy-type defects in semiconductors. The calculations
well reproduce prominent anisotropic momentum distribution observed for
pure crystals of diamond, silicon and germanium. As for aligned
divacancies in a Si crystal, theory reproduces experimental weak
anisotropy. It is clarified that this anisotropy reflects the
anisotropic structure of the defect, indicating that the 2D-ACAR is an
effective probe to obtain microscopic information on defects.
[TYPE]:Semimetals and Semiconductors
[PROP]:Positron Annihilation, 2D-ACAR, semiconductor, defect, first-principles
calculation,
******************************************************************************
[ID ]:KL97-080
[AUTH]:Saito Shin-hachiro, Kishi Hideki, Nie Kohji, Nakamaru Hisakazu,
Wagatsuma Fumihiko and Shinohara Takeshi
[TITL]:]63[Cu NMR Studies of Copper Sulfide
[SOUR]:Phys. Rev. B, 55[21] (1997), 14527-14535
[LAB ]:(2); Phys. Lab., Faculty of Eng., Toin Univ. of Yokohama; Gijutsu;
Yamayasu
[ABST]:We have measured the ]63[Cu NMR of powdered copper sulfide CuS, in the
region between 1.5 K and a room temperature, under magnetic field up to
6.5 T. An intense resonance peak and its satellites have been observed
at all of the measured temperatures. The intense peak consists of two
resonance lines above 60 K, and four lines below about 50 K. The
splitting corresponds to the reported crystalline distortion and
anomaly in specific heat below 55 K. There are complex satellites
around the central intense peak, which are attributable to the
first-and second-order quadrupole splittings. The Knight shifts of the
central intense peak are nearly temperature independent and range from
0.04 to 0.16% in the region between 1.6K and a room temperature. The
central peak and the observed satellites can be assigned to metallic
Cu(1) and less metallic Cu(2) in the crystalline structure of CuS. An
anomalous negative Knight shift is estimated for the metallic Cu(1).
The spin-lattice relaxations times, T[1] have also been measured for
both the Cu(1) and Cu(2) nuclei. T[1] for Cu(2) nuclei is about 55 ms
at 15 K, while that for Cu(1) nuclei is anisotropic and anomalously
short 4 ms at 15 K, which suggests the metallic character in the plane
formed by Cu(1)-S bonds.
[TYPE]:Semimetals and Semiconductors
[PROP]:CuS, NMR, superconductor, phase transformation
******************************************************************************
[ID ]:KL97-081
[AUTH]:Sekiguchi Takashi, Kusanagi Susumu and Sumino Koji
[TITL]:Two Dimensional EBIC Study of Extended Defects in Silicon
[SOUR]:Proc. The Kazusa Akademia Park Forum on the Science and Technology of
Silicon Materials, (1997), 369-372
[LAB ]:(2); Suezawa; SONY Corp.; NIPPON STEEL Corp.
[ABST]:A computer-aided electron-beam-induced-current (EBIC) system was
developed to study the electrical activity of extended defects in
semiconductors. In this system, EBIC images are recorded into two
dimensional arrays with retaining the absolute values of EBIC current,
which make it possible to analyze EBIC signals quantitatively. This
paper demonstrates the quantitative EBIC study of dislocations in
FZ-Si. We have distinguished the distribution of electrical activity
along dislocations and evaluated the energy levels of dislocations.
[TYPE]:Semimetals and Semiconductors
[PROP]:Si, EBIC, dislocation, debris, temperature dependence
******************************************************************************
[ID ]:KL97-082
[AUTH]:Sekiguchi Takashi, Ohashi Naoki and Terada Yoshihiro
[TITL]:Cathodoluminescence Study on the Hydrogenation of ZnO Luminescence
[SOUR]:Mater. Sci. Forum, 258-263 (1997), 1371-1376
[LAB ]:(1); Suezawa; Tokyo Inst. of Technol.
[ABST]:We have studied the luminescence property of ZnO single crystals by
means of cathodoluminescence. It was found that hydrogen plasma
strongly passivates the green emission and enhances the excitonic
luminescence of ZnO. The band edge luminescence shows strong
temperature dependence after hydrogenation and its intensity at low
temperatures becomes remarkably high. The effect of hydrogenation
disappears by an annealing at 700Ž, which indicates hydrogen is rather
strongly bound to the centers for green emission. This study indicates
that the passivation of deep levels is the key for the application of
ZnO crystals for the ultraviolet light source.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnO, cathodoluminescence, green emission, hydrogen, passivation
******************************************************************************
[ID ]:KL97-083
[AUTH]:Sekiguchi Takashi, Ohashi Naoki and Terada Yoshihiro
[TITL]:Effect of Hydrogenation on ZnO Luminescence
[SOUR]:Jpn. J. Appl. Phys., 36[3A] (1997), L289-L291
[LAB ]:(1); Suezawa; Dept. of Inorganic Mater., Faculty of Eng., Tokyo Inst.
of Technol.
[ABST]:The effect of hydrogenation on the luminescence property of ZnO crystal
was investigated by means of cathodoluminescence (CL). It was found
that hydrogen plasma treatment strongly passivates the green emission
and enhances the band edge luminescence. The band edge luminescence of
ZnO crystals in the as-grown state does not show any significant
temperature dependence. However, that of hydrogenated ZnO crystals
shows strong temperature dependence and the intensity increases
significantly at low temperatures. At 30 K, the number of luminescent
photons exceeds several tenths of generated electron-hole pairs.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnO, CL, green emission, excitonic luminescence, hydrogen passivation
******************************************************************************
[ID ]:KL97-084
[AUTH]:Shen Bo, Sekiguchi Takashi and Sumino Koji
[TITL]:Effect of Metallic Contamination on the Electrical Activity of
Frank-partial Dislocations in Cz-Si
[SOUR]:Proc. The Kazusa Akademia Park Forum on the Science and Technology of
Silicon Materials, (1997), 373-376
[LAB ]:(2); Dept. of Phys., Nanjing Univ.; Suezawa; NIPPON STEEL Corp.
[ABST]:The effect of Cu, Ni, and Fe contamination on Frank-partial
dislocations in Cz-grown Si was studied by means of electron beam
induced current (EBIC) and transmission electron microscope (TEM). It
was elucidated that the segregation behavior of transition metal
impurities on Frank-partials depends not only on the impurity species
but also on the cooling rate of the specimen after contamination.
[TYPE]:Semimetals and Semiconductors
[PROP]:CZ-Si, Cu, Ni, Fe, EBIC, stacking fault, contamination
******************************************************************************
[ID ]:KL97-085
[AUTH]:Shen Bo, Zhang X.Y, Yang K., Chen P., Zhang R., Shi Y., Zheng Y.D
[TITL]:Gettering of Fe Impurities by Bulk Stacking Faults in Czochralski-Grown
Silicon
[SOUR]:Appl. Phys. Lett., 70[14] (1997), 1876-1878
[LAB ]:(2); Dept. of Phys. and Inst. of Solid State Phys., Nanjing Univ.;
Suezawa
[ABST]:Gettering of Fe impurities by bulk stacking faults in Czochralski-grown
silicon are investigated by means of the electron-beam-induced-current
technique and transmission electron microscopy. It is found that Fe
impurities only precipitate on Frank partial dislocations bounding
stacking faults when the specimen is cooled slowly; however, both Frank
partials and fault planes are decorated by Fe impurities when the
specimen is cooled rapidly. It is explained that small oxygen
precipitates on fault planes serve as the gettering centers for Fe
impurities in the fast cooled specimen.
[TYPE]:Semimetals and Semiconductors
[PROP]:CZ-Si, Fe, EBIC, TEM, stacking faults, Fe gettering, Frank partial,
temperature dependence, contamination, oxygen precipitate
******************************************************************************
[ID ]:KL97-086
[AUTH]:Suezawa Masashi
[TITL]:Optical Absorption Due to Hydrogen Bound to Interstitial Si in Si
Crystal Grown in Hydrogen Atmosphere
[SOUR]:Mater. Sci. Forum, 258-263 (1997), 229-234
[LAB ]:(3); Suezawa
[ABST]:We studied optical absorption spectrum of Si crystal grown in a
hydrogen ambient. Specimens were grown by the floating-zone grown
method in hydrogen atmosphere of 1 atm. Optical absorption spectra of
those specimens were measured at 6 K. Many optical absorption lines
were observed in the range of 1900 to 2200 cm]-1[. They were observed
only when the concentrations of carbon or boron were high. To
understand these results, we refered a report according to which
so-called A-type swirl, an interstitial type dislocation loop, was
observed when impurities of smaller covalent radius than that of Si
were doped. Hence we concluded that the above optical absorption lines
were due to localized vibration hydrogen atoms bound to interstitial Si
atoms.
[TYPE]:Semimetals and Semiconductors
[PROP]:Si, optical absorption, interstitial Si
******************************************************************************
[ID ]:KL97-087
[AUTH]:Suezawa Masashi
[TITL]:Point Defects at High Temperature Studied by the Measurement of Optical
Absorption Spectra of Si
[SOUR]:Proc. The Kazusa Akademia Park Forum on the Science and Technology of
Silicon Materials, (1997), 116-123
[LAB ]:(3); Suezawa
[ABST]:We reported in this paper optical absorption spectra of two kinds of Si
crystals, namely, those grown in a hydrogen ambient and those quenched
after annealing at high temperatures in a hydrogen ambient. In the
first study, specimens were grown by the floating-zone growth method in
a hydrogen ambient of 1 atm. Optical absorption spectra of those
specimens were measured at 6 K. Many optical absorption lines were
observed in the range of 1900 to 2200cm]-1[. They were observed only
when the concentrations of carbon or boron were high. To understand
these results, we referred to a report according to which a so-called
A-type swirl, an interstitial-type dislocation loop, was observed when
impurities of smaller covalent radii than that of Si were doped. Hence,
we concluded that the above optical absorption lines were due to
localized vibration of hydrogen atoms bound to interstitial Si atoms.
We proposed a new method to investigate properties of interstitial Si
atom, namely, optical absorption measurement of quenched specimens
after annealing in a hydrogen ambient. In the second study, we applied
the above method to gold- and zinc-doped Si crystals since the
concentration of interstitial Si was expected to be high because of the
kick-out mechanism of their diffusion. We obtained the formation energy
of interstitial Si to be about 2.1eV and 2.6eV, respectively, in the
above specimens.
[TYPE]:Semimetals and Semiconductors
[PROP]:Si, optical absorption, point defect
******************************************************************************
[ID ]:KL97-088
[AUTH]:Takahashi Hideki, Suezawa Masashi and Sumino Koji
[TITL]:Size Effect of Shallow Acceptor Impurities on Formation Process of
Iron-Acceptor Pairs in Silicon
[SOUR]:Shallow-Level Centers in Semiconductors, ed. by C.A.J. Ammerlaan & B.
Pajot, Amsterdam, 1996, (1997), 511-516
[LAB ]:(2); Process Development Division, Fujitsu Ltd.; Suezawa; Sumino
[ABST]:Shallow acceptor impurities, B, Al, Ga and In, interact with transition
metals in silicon and lose their shallow levels. The typical example is
the case of iron (Fe). Fe-acceptor pairs have two structural
configurations, trigonal and orthorhombic symmetries. The energy
difference between the two configurations, and the formation process of
Fe-acceptor pairs are closely related to the size of shallow acceptor
impurities. In this paper, we show the size effect of acceptors on the
formation process of the pairs.
[TYPE]:Semimetals and Semiconductors
[PROP]:Si, Fe, acceptor, pair
******************************************************************************
[ID ]:KL97-089
[AUTH]:Tanaka Kazuhiro and Suezawa Masashi
[TITL]:Photoluminescence of Deformed Bulk Crystals of Si-Ge Alloy
[SOUR]:Shallow-Level Centers in Semiconductors, ed. by C.A.J. Ammerlaan & B.
Pajot, Amsterdam, 1996, (1997), 333-338
[LAB ]:(1); Suezawa
[ABST]:We showed peculiar shifts of D1 and D2 lines in deformed Si-Ge alloy
depending on the deformation and annealing temperatures. Alloy crystals
were grown by the Czochraski method. Specimens were deformed in
compression between 700 and 900Ž in an argon atmosphere.
Photoluminescence spectra were measured at 4.2K. Peak positions of D1
and D2 lines depended on the deformation temperatures, at higher
energies at higher energies at higher temperatures of deformation. On
the other hand, those of D3 and D4 lines did not depend on the
deformation temperature. The magnitudes of peak shifts of D1 and D2
lines were proportional to t]2/3[ at the short duration of annealing
time (t) at around 650Ž. The activation energy was determined to be
2.5eV which was much smaller than that of selfdiffusion. These results
were interpreted to be due to the change of alloy composition around
dislocations caused by the elastic interaction between dislocations and
constituent atoms, Si and Ge.
[TYPE]:Semimetals and Semiconductors
[PROP]:Si, Ge, deformation, photoluminescence
******************************************************************************
[ID ]:KL97-090
[AUTH]:Tang Zheng, Hasegawa Masayuki, Chiba Toshinobu, Saito Mineo, Sumiya
Hitoshi, Li Zhi Qiang, Akahane Takashi, Kawazoe Yoshiyuki and Yamaguchi
Sadae
[TITL]:Positron 2D-ACAR in Perfect Crystals of Diamond, Si and Ge:
First-Principles Calculations and Experiments
[SOUR]:Mater. Sci. Forum, 255-257 (1997), 411-413
[LAB ]:(3); Hasegawa; National Inst. for Res. in Inorganic Mater.; NEC
Informatec System, Ltd.; Itami Res. Lab., Sumitomo Electric Industries
Ltd.; Kawazoe; Yamasada
[ABST]:Positron annihilation characteristics in perfect crystals of diamond,
Si and Ge are studied theoretically and experimentally. A
first-principles calculation based on the two-component density
functional theory is presented. Calculations are found to be in good
agreement with our measurements. An interesting difference among
experimental two-dimensional angular correlation of annihilation
radiation (2D-ACAR) for diamond, Si and Ge is clarified by band by band
decomposition for the calculated three-dimensional momentum
distributions.
[TYPE]:Semimetals and Semiconductors
[PROP]:semiconductor, Positron Annihilation, 2D-ACAR, first-principles
calculation, electronic structure
******************************************************************************
[ID ]:KL97-091
[AUTH]:Tang Zheng, Hasegawa Masayuki, Chiba Toshinobu, Saito Mineo, Kawasuso
Atsuo, Li Zhi Qiang, Fu Rong Tang, Akahane Takashi, Kawazoe Yoshiyuki
and Yamaguchi Sadae
[TITL]:Anisotropy in the Positron 2D Angular Correlation of Annihilation
Radiation for Singly Negative Divacancies in Si
[SOUR]:Phys. Rev. Lett., 78[11] (1997), 2236-2239
[LAB ]:(2); Yamasada; National Inst. for Res. in Inorganic Mater.; NEC
Informatec Systems, Ltd.; Sumino; Kawazoe
[ABST]:Interesting features of position two-dimensional angular correlation of
annihilation radiation (2D-ACAR) distribution for singly negative
divacancies in Si are studied experimentally and theoretically.
Anisotropy of the distribution is successfully detected for a specimen
with aligned divacancies and is well reproduced by first-principles
calculations based on the two-component density-functional theory. The
present calculation demonstrates that the anisotropy reflects the
characteristic distribution of electrons around the divacancies,
indicating that the 2D-ACAR is an effective tool to provide microscopic
information on vacancy-type defects.
[TYPE]:Semimetals and Semiconductors
[PROP]:Si, positron, divacancy, 2D-ACAR
******************************************************************************
[ID ]:KL97-092
[AUTH]:Tomasini Pierre, Arai Kenta, Lu Fang, Zhu Ziqiang, Yao Takafumi,
Sekiguchi Takashi, Suezawa Masashi, Shen Mengyan, Goto Takenari, Yasuda
Takashi and Segawa Yuusaburo
[TITL]:Optical Properties of ZnSe/ZnS Quantum Wire Structures When Using High
Index Substrates
[SOUR]:Nonlinear Opt., 18[2-4] (1997), 215-218
[LAB ]:(2); Yao; Suezawa; Dept. of Phys., Tohoku Univ.; Photodynamics Res.
Center, RIKEN
[ABST]:ZnSe/ZnS Quantum wire structures were grown by Molecular Beam Epitaxy
on unpatterned GaP(h11) A substrates, where h=2,3,5,7. The PL peak
positions of the structures are found to be linearly dependent on the
crystallographic orientation, when comparing samples grown with the
same experimental conditions. We analysed our data in the frame of
Quantum Confined Stark Effect.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe/ZnS quantum wires, high index substrates, PL
******************************************************************************
[ID ]:KL97-093
[AUTH]:Wang J, Zhu Z, Park K.
[TITL]:Hot Plasma Chemical Vapor Deposition of GaN on GaAs(100) Substrate
[SOUR]:J. Electron. Mater., 26[3] (1997), 232-236
[LAB ]:(2); Yao; Hiraga
[ABST]:GaN films have been deposited on GaAs(100) substrates by a novel growth
technique, hot plasma chemical vapor deposition. A radio frequency N
plasma source with high power, up to 5 kW, provides an abundance of
nitrogen atoms during growth. In addition, strong ultraviolet emissions
from the hot plasma irradiate onto the substrate and promote the
dissociation of triethylgallium, this results in growth of GaN at very
low temperature (even at room temperature). In this paper, we describe
the characteristics of hot nitrogen plasma and present the results of
the low temperature growth of GaN. In addition, we have investigated
the effects of the nitridation of GaAs substrates. Reflection high
energy electron diffraction indicates the formation of a surface cubic
nitrided layer on the pretreated GaAs. The GaN films grown on fully
nitrided GaAs (100) substrates are of dominantly cubic structures.
[TYPE]:Semimetals and Semiconductors
[PROP]:GaN, plasma CVD, epitaxial growth
******************************************************************************
[ID ]:KL97-094
[AUTH]:Wang Shu Qi, Lu Fang, Jung Hyun Don, Song Chung Dam, Zhu Zi Qiang,
Okushi Hideyo, Cavenett Brian Clifford and Yao Takafumi
[TITL]:Electronic States in ZnSe/ZnTe Type-II Superlattice Studied by
Capacitance Transient Spectroscopy
[SOUR]:J. Appl. Phys., 82[7] (1997), 3402-3407
[LAB ]:(1); Yao; Fundamental Mater. Technol. Center, Samsung Display Devices
Co., Ltd.; Electrotechnical Lab.; Dept. of Phys., Heriot-Watt Univ.
[ABST]:We have studied the electronic states in N-doped ZnSe/ZnTe type-II
superlattice (SL) by deep level transient spectroscopy (DLTS) and
isothermal capacitance transient spectroscopy (ICTS). The capture and
emission processes of holes between a miniband of the SL and the
valence band of ZnSe barrier were investigated. From the analysis of
DLTS and ICTS spectra, the activation energy for the hole emission from
the miniband energy level was determined to be 0.28 pm 0.03eV, which is
consistent with a theoretical value (0.25eV) of the band offset between
the ZnSe/ZnTe SL calculated based on the Kronig-Penney model. A deep
level with an activation energy of 0.48 pm 0.03eV was observed and has
been assumed to originate from an interface defect in the SL region. A
deep level located at 0.54 pm 0.03 eV above the valence band of ZnSe
was also observed in the ZnSe capping layer.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe/ZnTe type-II superlattice, capacitance transient spectroscopy
******************************************************************************
[ID ]:KL97-095
[AUTH]:Watanabe Takehito and Suezawa Masashi
[TITL]:Shift of Photoluminescence Peak in Highly Self-Compensated Ge-Doped
GaAs
[SOUR]:Shallow-Level Centers in Semiconductors, ed. by C.A.J. Ammerlaan & B.
Pajot, Amsterdam, 1996, (1997), 263-268
[LAB ]:(2); Suezawa
[ABST]:We found peculiar shift of photoluminescence peak depending on the Ge
concentration and explained this with recombination of carriers at
donor-acceptor pairs in highly compensated specimens. Specimens were Ge
doped GaAs grown by the liquid-encapsulated Czochralski method. The
Hall effect at room temperature and photoluminescence at 4.2 K were
measured. Carrier concentrations were smaller than those of Ge by more
than one order of magnitude which indicated high compensation.
Photoluminescence peak at maximum energy shifted to lower energy as the
Ge concentration increased. This behavior was explained with
recombination of carriers at donor-acceptor pairs in spatially
separated potential wells.
[TYPE]:Semimetals and Semiconductors
[PROP]:GaAs, Ge, photoluminescence, self-compensation
******************************************************************************
[ID ]:KL97-096
[AUTH]:Watanabe Taketo and Suezawa Masashi
[TITL]:Near Band-Gap Photoluminescence Peak of Ge-Doped GaAs
[SOUR]:Jpn. J. Appl. Phys., 36[11] (1997), 6787-6792
[LAB ]:(3); Suezawa
[ABST]:The objective of our research was to clarify the origin of the peculiar
shift of the photoluminescence (PL) peak near the band gap energy to
low energy accompanied with the increase of Ge concentration in GaAs.
Specimens of Ge-doped bulk GaAs were grown by the liquid-encapsulated
Czochraski method. We measured the Hall effect at room temperature and
PL spectrum at 4.2 K. Carrier concentrations were smaller than those of
Ge by more than one order of magnitude which indicated high
compensation. The PL peak near the band gap energy shifted to low
energy as the Ge concentration increased. This PL peak shifted to low
energy, as the excitation energy decreased, as the excitation intensity
decreased and as the measurement temperature increased. This behavior
was explained qualitatively by the model of recombination of carriers
at donor-acceptor pairs in spatially separated potential wells which
were built due to a fluctuation in the distribution of highly doped
donors (Ge at Ga atom site) and acceptors (Ge at As atom site).
[TYPE]:Semimetals and Semiconductors
[PROP]:GaAs, Ge, photoluminescence, band-gap
******************************************************************************
[ID ]:KL97-097
[AUTH]:Wu Yihong, Arai Kenta, Kuroda Noritaka, Yao Takafumi, Yamamoto Aishi,
Shen Mengyan and Goto Takenari
[TITL]:Optical Properties of Manganese-Doped ZnSe/ZnS Quantum Dots Grown by
Molecular Beam Epitaxy
[SOUR]:Jpn. J. Appl. Phys., 36[12B] (1997), L1648-L1650
[LAB ]:(2); Yao; Faculty of Sci. Tohoku Univ.
[ABST]:Optical properties of Mn-doped ZnSe/ZnS quantum dots (QD's) have been
investigated by both steady-state and time-resolved photoluminescence
(PL) measurements. Strong photoluminescence associated with Mn intra-d
shell transitions has been observed for QD's with longitudinal
thickness of just few monolayers (ML's). The PL decay involves two
processes with different lifetimes of which the faster on has a
lifetime of about 5mu s which is almost independent of the well
thickness, while the other process has a lifetime varying from 40 to 80
mu s when the well width decreases from 6 to 0.25 ML. The experimental
results are interpreted by the use of rate equations which suggests
that the enhanced Mn emission might be due to the relatively enhanced
energy transfer from the QD's to the Mn atoms.
[TYPE]:Semimetals and Semiconductors
[PROP]:quantum dots, Mn-doped ZnSe, optical properties
******************************************************************************
[ID ]:KL97-098
[AUTH]:Xue Qi Kun, Hasegawa Yukio, Ogino Tsuyoshi, Kiyama Hisashi and Sakurai
Toshio
[TITL]:Indium-Rich 4 times 2 Reconstruction in Novel Growth of InAs on the
GaAs(001)
[SOUR]:Sci. Rep. RITU, A44[2] (1997), 153-156
[LAB ]:(3); Sakurai
[ABST]:Molecular beam epitaxy (MBE) of the lattice mismatched InAs/GaAs(001)
system is studied by in situ scanning tunneling microscopy (STM) and
reflection high energy electron diffraction (RHEED). We found that
deposition of submonolayer (sim0.6ML) In on the GaAs(001)-As-rich 2
times 4-beta surface could result in a new 4 times 2 reconstruction,
and that if the growing front maintains this reconstruction, the
multiplayer InAs grows two-dimensionally and the commonly observed
three-dimensional islanding is completely surpressed. The atomic
structure for this new 4 times 2 reconstruction is discussed on the
basis of voltage-dependent STM images. In addition, a "domain wall"
structure is discussed, representing a new type of strain relief
mechanism in the layer-by-layer growth reported here.
[TYPE]:Semimetals and Semiconductors
[PROP]:InAs, GaAs, interface,STM
******************************************************************************
[ID ]:KL97-099
[AUTH]:Xue Qi Kun, Hashizume Tomihiro, Ichimiya Ayahiko, Ohno Takahisa,
Hasegawa Yukio and Sakurai Toshio
[TITL]:Scanning Tunneling Microscopy of the GaAs(001) Surface Reconstructions
[SOUR]:Sci. Rep. RITU, A44[2] (1997), 113-143
[LAB ]:(2); Sakurai; Hitachi Ltd.; Nagoya Univ.; National Res. Inst. for Met.
[ABST]:The atomic structure of the GaAs(001) surface has been disputed since
molecular beam epitaxy (MBE) technique was developed in the earlier
nineteen sixties. The invention of scanning tunneling microscopy (STM)
with its real-space atom-resolution capability, has revolutionized the
situation. This paper reviews the STM investigations of the principal
reconstructions found on the GaAs (001) surface, As-rich 2 times 4 and
2 times 6, Ga-rich 4 times 2 and 4 times 6. These studies, together
with advanced theoretical analyses, have finally resulted in
establishment of a unified structural model for various
reconstructions, with which we can explain most of the observations and
long-standing controversies about the atomic structures and surface
stoichiometries.
[TYPE]:Semimetals and Semiconductors
[PROP]:III-V compound semiconductor, MBE, STM
******************************************************************************
[ID ]:KL97-100
[AUTH]:Yao Takafumi and Wu Yihong
[TITL]:Molecular Beam Epitaxial Growth and Optical Properties of Undoped and
Manganese-Doped ZnSe/ZnS Quantum Dots
[SOUR]:J. Korean Phys. Soc., 31[3] (1997), 465-470
[LAB ]:(3); Yao
[ABST]:Ultrathin ZnSe/ZnS quantum wells (QWs) have been fabricated using
molecular beam epitaxy (MBE). Temperature-dependent photoluminescence
(PL) measurement revealed that the QWs are essentially
three-dimensionally confined quantum dot (QD) structures when the well
width is below 3 monolayers (MLs). The lateral dot size distribution is
estimated through fitting with experimental photoluminescence line
shapes. A good agreement between theoretical and experimental data was
obtained for the three monolayer sample by assuming a Gaussian
distribution with a mean diameter of 29 angstrom and a characteristic
width of 5angstrom. Manganese was subsequently introduced into the
quantum dots and wells. Strong photoluminescence associated with Mn
intra-d shell transitions has been observed for QDs with a longitudinal
thickness of just few monolayers(MLs). The PL decay involves two
processes with different lifetimes of which the faster one has a
lifetime of about 5mu s which is almost independent of well thickness,
while the other process has a lifetime varying from 40 to 80mu s when
the well width decreases from 6 to 0.25 ML. Since both processes are at
least three orders of magnitude slower than the decay of Mn emission in
ZnS nanocrystals reported by R.N.Bhargava et al. [Phys. Rev. Lett. 72,
416 (1994)], a different model has been invoked to explain the
experimental results obtained in this work. Based on this model, the
enhanced Mn emission should be attributed mainly to the relatively
enhanced energy transfer from QDs to Mn atoms rather than the lifetime
shortening of Mn emission itself. The possibility of utilizing the
phonon bottleneck problem in a positive way to enhance the energy
transfer in doped QDs is discussed on a general base.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe/ZnS quantum dots, MBE, Mn-doped ZnSe
******************************************************************************
[ID ]:KL97-101
[AUTH]:Yao Takafumi, Lu Fang, Cho Meoung Whan, Koh Kwang Wook, Zhu Ziqiang,
Kuo Li Hsin, Yasuda Tetsuji, Ohtake Akihiro, Miwa Shiro, Kimura Kozo,
Nakajima Kaoru and Kimura Kenji
[TITL]:Heterovalent ZnSe/GaAs Interfaces
[SOUR]:Phys. Status Solidi B, 202[2] (1997), 657-668
[LAB ]:(2); Yao; Joint Res. Center for Atom Technol.; Dept. of Eng. Phys. and
Mechanics, Kyoto Univ.
[ABST]:This paper describes the characterization of the heterovalent interface
of ZnSe/GaAs, which is a closely lattice-matched heterostructure
system, and the effects of the interface chemistry on the growth mode
and defect generation. We prepare interfaces having different chemical
compositions by exposing Zn, Se, or Te prior to ZnSe growth on
GaAs(001) surfaces with different surface stoichiometries. Depending on
the surface preparation and growth procedures, the interface chemistry
varies from a Ga-Se bond dominated interface to a Zn-Se bond dominated
one. The interface chemistry causes a rearrangement of the interface
structure to satisfy charge neutralization, which chemistry causes a
rearrangement of the interface structure to satisfy charge
neutralization, which should affect the growth mechanism and the defect
generation as well. The defect generation is well correlated with the
interface chemistry, while the growth mode is rather correlated not
only with the energetics but also the kinetics of the surface. We
propose (110) growth as an alternative to (100) growth to avoid
heterovalence problems of the present ZnSe-based light emitting
devices.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe/GaAs interface, heterovalent interface
******************************************************************************
[ID ]:KL97-102
[AUTH]:Yasuda Tetsuji, Kimura Kozo, Miwa Shiro, Kuo Li Hsin, Ohtake Akihiro,
Jin Cheng Guo, Tanaka Kazunobu and Yao Takafumi
[TITL]:Reflectance-Difference Studies of Interface-Formation and
Initial-Growth Processes in ZnSe/GaAs(001) Heteroepitaxy
[SOUR]:J. Vac. Sci. Technol., B, 15[4] (1997), 1212-1220
[LAB ]:(2); Joint Res. Center for Atom Technol.; Yao
[ABST]:In situ reflectance-difference studies of initial stages of ZnSe growth
on GaAs(001) surfaces are reported. ZnSe layers with thicknesses less
than 4 nm were grown by molecular beam epitaxy in both layer-by-layer
and island-growth modes. It is found that the reflectance-difference
spectra for this thickness as well as on the growth mode. This
observation indicates that the surface electronic structure develops
with thickness and in a manner sensitive to the mid- or long-range
order of the surface. The interface-induced peak at 2.8 eV, intensity
of which is correlated with the extent of the interfacial Ga-Se bond
formation, is pinned during the course of growth, which indicates that
atomic rearrangement or mixing at the interface is minimal once several
monolayers of ZnSe are deposited on GaAs.
[TYPE]:Semimetals and Semiconductors
[PROP]:ZnSe/GaAs heteroepitaxy, RDS
******************************************************************************
[ID ]:KL97-103
[AUTH]:Chen Lidong, Goto Takashi, Li Jianhui and Hirai Toshio
[TITL]:Microstructure and Thermoelectric Property of Arc-melted Silicon
Borides (in Japanese)
[SOUR]:Funtai oyobi Funmatsu Yakin (J. Jpn. Soc. Powder Powder Metall.), 44
(1997), 55-59
[LAB ]:(3); Hirai
[ABST]:Silicon borides were prepared by arc melting in argon atmosphere using
silicon and boron powders in a boron content range from 80 to 94mol%.
As-melted specimens consisted of SiB[n] and free Si. The contents of
free Si decreased from 30 to 3vol% as the boron content in raw material
increased from 80 to 94mol%. The as-melted specimens were heat-treated
in argon atmosphere at temperatures of 1400 to 1700K. During heat
treatment, free Si reacted with SiB[n] near the SiB[n]-Si boundary to
from SiB[4], and as the result SiB[n]-SiB[4] composites showed larger
electrical conductivity and smaller thermal conductivity than the
as-melted specimens, which contributes to improvement of
thermoelectrical property.
[TYPE]:Semimetals and Semiconductors
[PROP]:silicon boride, thermoelectric property, arc-melting
******************************************************************************
[ID ]:KL97-104
[AUTH]:Chen Lidong, Goto Takashi, Tu Rong and Hirai Toshio
[TITL]:Oxidation Behavior of Oxidation-resistive Glass-coated PbTe (in
Japanese)
[SOUR]:Funtai oyobi Funmatsu Yakin (J. Jpn. Soc. Powder Powder Metall.), 44[7]
(1997), 653-657
[LAB ]:(3); Hirai
[ABST]:Oxidation behavior of lead telluride (PbTe) and glass-coated PbTe was
studied at oxygen partial pressures of 10Pa to 0.1Mpa in the
temperature range between 700 to 900K. Mass loss was observed at
moderately low oxygen partial pressures and at high temperatures, while
mass gain was observed at high oxygen partial pressures and at low
temperatures. For the samples which showed mass loss, Pb[3]TeO[5] or
Pb[5]TeO[7] formed on the PbTe surface. The formation of PbTeO[3] layer
or Pb[2]TeO[4]/PbTeO[3] multi-layer caused the mass gain. Oxidation
resistance of PbTe was improved by the glass-coating. No mass change
was observed up to 20ks.
[TYPE]:Semimetals and Semiconductors
[PROP]:PbTe, thermoelectric, oxidation
******************************************************************************
[ID ]:KL97-105
[AUTH]:Chen Lidong, Goto Takashi and Hirai Toshio
[TITL]:Thermoelectric Properties of Arc-melted Silicon Borides
[SOUR]:Functionally Graded Materials, ed. by I. Shiota and Y. Miyamoto,
Tsukuba, 1996, (1997), 557-562
[LAB ]:(3); Hirai
[ABST]:Silicon borides were prepared by arc melting in a boron content range
from 80 to 94mol%. As-melted specimens consisted of SiB[n] and free
silicon. After heat treatment at 1500-1673K, SiB[4] formed near the
SiB[n]-Si boundary due to the solid reaction between free silicon and
SiB[n], and as the result SiB[n]-SiB[4] composites were obtained. The
SiB[n]-SiB[4] composites showed larger electrical conductivity and
smaller thermal conductivity than the as-melted silicon borides, which
leads to an improvement of thermoelectric figure of merit.
[TYPE]:Refractory Materials and Ceramics
[PROP]:silicon boride, thermoelectric, arc-melting
******************************************************************************
[ID ]:KL97-106
[AUTH]:El-Eskandarany M.
[TITL]:Mechanically Induced Carbonization for Formation of Nanocrystalline TiC
Alloy
[SOUR]:Sci. Rep. RITU, A43[2] (1997), 181-193
[LAB ]:(2); Suzuki Hirai
[ABST]:A single phase of NaCl-type structure of Ti[44]C[56] alloy powder has
been synthesized by ball-milling elemental Ti and graphite powders at
room temperature. The end-product of Ti[44]C[56] that is obtained after
720ks of milling consists of the grains of about 3nm in diameter and
possesses homogeneous powder with an average particle diameter of less
than 0.4mu m. The milled powder has been consolidated into bulk
samples, using a plasma activated sintering method. This consolidation
step leads to the formation of fully-dense TiC compacts with
nano-structure grains. The as-milled powder and the as-consolidated
bulk samples have been characterized after selected milling times by
means of X-ray diffraction, transmission electron microscope, scanning
electron microscope and chemical analyses. Some of the compacted
samples were investigated by small-angel X-ray scattering and
high-resolution transmission electron microscope. The hardness and some
mechanical properties of the end-product are reported. On the basis of
the results of the present study, the ball-milling technique
accompanied with plasma activated sintering can provide powerful tools
for fabrication of nanocrystalline TiC bulk alloys.
[TYPE]:Refractory Materials and Ceramics
[PROP]:mechanical alloying, titanium carbide, consolidation, nanocrystalline
materials, transmission electron microscopy
******************************************************************************
[ID ]:KL97-107
[AUTH]:Gang He, Hayasaka Yasukazu, Narushima Takayuki, Goto Takashi, Hirai
Toshio and Iguchi Yasutaka
[TITL]:Preparation of Sr $beta-Alumina Ionic Conductors and Their a.c.
Impedance Measurements
[SOUR]:J. Ceram. Soc. Jpn., 105[12] (1997), 1067-1071
[LAB ]:(1); Dept. of Metall., Faculty of Eng., Tohoku Univ.; Hirai
[ABST]:beta-alumina type ionic conductors were synthesized in the
SrO-MgO-Al[2]O[3] system by a direct sintering method and their
electrical conductivity was measured at 873 to 1373 K by an a.c.
impedance method in order to apply the beta-alumina to solid
electrolyte of a gas sensor at high temperatures. Sr beta-aluminas in a
single phase were obtained in the composition range of SrO: MgO:
Al[2]O[3]=1:1:4.8-5.2 .The bulk and grain boundary conductivities were
separated from the total conductivity at SrO:MgO:Al[2]O[3]=1:1:4.8 and
1:1:5.0. The bulk conductivity of the Sr beta-alumina was around 6.7
times 10]-3[S cdot m]-1[ at 1373K.
[TYPE]:Refractory Materials and Ceramics
[PROP]:beta-alumina, ionic conductor, a.c. impedance, transport number
******************************************************************************
[ID ]:KL97-108
[AUTH]:Goto Takashi, Li Jian Hui, Hirai Toshio, Maeda Yukio, Kato Ryozo and
Maesono Akikazu
[TITL]:Measurements of the Seebeck Coefficient of Thermoelectric Materials by
an AC Method
[SOUR]:Int. J. Thermophys., 18[2] (1997), 569-577
[LAB ]:(2); Hirai; SHINKO-RIKO Inc.
[ABST]:An ac method for measurement of the Seebeck coefficient was developed.
Specimens were heated periodically at frequencies in the range 0.2-10
Hz using a semiconductor laser. The small temperature increase and the
resultant thermoelectric power were measured with a Pt-Pt 13% Rh
thermocouple (25mu m in diameter) through a lock-in amplifier. The
Seebeck coefficient of a Pt[90]Rh[10] foil measured by the ac method
was in agreement with that obtained from the standard table. The
optimum frequency and specimen thickness for the ac method were 0.2 Hz
and 0.1-0.2 mm, respectively. The Seebeck coefficients of silicon
single crystal and several thermoelectric semiconductors (Si[80]Ge[20],
PbTe, FeSo[2], SiB[14]) measured by ac method agreed with those
measured by a conventional dc method in the temperature range between
room temperature and 1200K. The time needed for each measurement was
less than a few tens of minutes, significantly shorter than for a
conventional dc method.
[TYPE]:Refractory Materials and Ceramics
[PROP]:AC method, seebeck coefficient, thermoelectric properties,
silicon-germanium
******************************************************************************
[ID ]:KL97-109
[AUTH]:Goto Takashi, Li Jianhui and Hirai Toshio
[TITL]:Thermoelectric Properties of B[4]C-Based Composite Ceramics Prepared by
Arc-Melting
[SOUR]:Proc. 11th Int. Conf. Composite Materials, ed. by M.L. Scott,
Australia, (1997), 603-612
[LAB ]:(2); Hirai
[ABST]:B-C system solid solutions and B[4]C-based composites (B[4]C-SiC system
and B[4]C-TiB[2]system) were prepared by arc-melting in an argon
atmosphere. The microstructure and thermoelectric properties were
studied. The solid solutions of the B-C system ranged between 10 and 25
at%C, and the dimension-less thermoelectric figure-of-merit (ZT) was
the greatest at the composition of 25 at%C (B[4]C). Both the B[4]C-SiC
and B[4]C-TiB[2] systems were quasi-binary, and typical lamellar
structures were observed indicating eutectic reactions. In the SiC-B[4]
system, the eutectic composition was 45mol%SiC, and the ZT value was
the highest at 40mol%SiC. In the B[4]C-TiB[2] system 25mol%TiB[2] was
the eutectic composition and the ZT showed the maximum values at
6mol%TiB[2]. The greatest ZT value of 0.55 at 1100K was obtained in the
B[4]C-TiB[2] system at 6mol%TiB[2].
[TYPE]:Refractory Materials and Ceramics
[PROP]:boron carbide, silicon carbide, titan boride, thermoelectric,
arc-melting
******************************************************************************
[ID ]:KL97-110
[AUTH]:Goto Takashi, Ono Takashi and Hirai Toshio
[TITL]:Preparation of Iridium Films by MOCVD and Their Application for Oxygen
Gas Sensors
[SOUR]:Inorg. Mater., 33[10] (1997), 1017-1021
[LAB ]:(2); Hirai; Riken Co., Ltd.
[ABST]:Iridium films were prepared by metalorganic chemical vapor deposition
(MOCVD) on zirconia solid electrolyte substrates using iridium
acetylacetonate as a precursor. The films prepared without oxygen gas
addition were black and contained 35 to 70vol% amorphous carbon
surrounding iridium grains 1 to 3nm in diameter. The Ir-C films showed
excellent electrical and catalytic properties for ZrO[2] as a
reversible electrode at temperatures below 800 K. The impedance
associated with the ZrO[2]/Ir-C interface was about 3 to 5 times
smaller than that of commercial platinum electrodes at 773 K. By adding
a small amount of oxygen gas in the source gas, the carbon content of
the films was decreased significantly, with accompanying grain growth
of Ir and degradation of electrical performance. The output current of
Ir-C films containing a small amount of carbon (about 1 wt % C) still
was four times greater than that of commercial electrodes at 773 K.
[TYPE]:Refractory Materials and Ceramics
[PROP]:iridium, carbon, nano-composite, oxygen gas sensor, MOCVD
******************************************************************************
[ID ]:KL97-111
[AUTH]:Hirotsu Yoshihiko, Wakoh Kimio, Suzuki Kenji, Sumiyama Kenji, Yamamuro
Saeki, Kamiyama Tomoaki, Shibuya Masaki and Yamamura Taketami
[TITL]:High-Resolution TEM Observation of beta-SiC Nano-Crystallite Evolution
in Si-C-Ti-O Fibers Pyrolyzed from Polytitanocarbosilane Precursor
[SOUR]:Mater. Trans., JIM, 38 (1997), 5-10
[LAB ]:(2); Previous Address: Dept. of Mechanical Eng., Nagaoka Univ. of
Technol. Present Address: The Inst. of Scientific and Industrial Res.,
Osaka Univ.; Gijutsu; Suzuki; Ube Res. Lab., Corporate Res. and
Development, Ube Industries Ltd.
[ABST]:Si-C-Ti-O fibers pyrolyzed from polytitanocarbosilane polymer
precursors have been observed by a high-resolution transmission
electron microscope. Nano-crystalline clusters are finely dispersed in
the amorphous matrices of Si-C-Ti-O fibers made from
thermal-oxidation-cured and electron-irradiation-cured precursors.
Nano-beam electron diffraction and simulated patterns demonstrate that
these clusters are beta-SiC. Such cluster formation is enhanced in the
specimens heat-treated at a high temperature and cured by
electron-irradiation.
[TYPE]:Refractory Materials and Ceramics
[PROP]:silicon-carbide fiber, transmission-electron microscopy,
nano-crystallite, organic-inorganic transformation
******************************************************************************
[ID ]:KL97-112
[AUTH]:Kurishita Hiroaki, Kitsunai Yuji, Kayano Hideo, Hiraoka Yutaka, Takida
Tomohiro and Igarashi Tadashi
[TITL]:Development of Molybdenum Alloy with High Toughness Even after
High-Temperature Heating and Neutron Irradiation
[SOUR]:Proc. 14th Int. Plansee Semin., ed. by G. Kneringer, et al., (1997),
287-300
[LAB ]:(2); Kayano; Dept. of Appl. Phys., Okayama Univ. of Sci.; Tokyo
Tungsten Co. Ltd.
[TYPE]:Refractory Materials and Ceramics
[PROP]:molybdenum, embrittlement, recrystallization, neutron irradiation,
radiation induced ductilization
******************************************************************************
[ID ]:KL97-113
[AUTH]:Saneyasu Masaaki, Hasegawa Masayuki, Tang Zheng, Tabata Makoto,
Fujinami Masanori, Ito Yasuo and Yamaguchi Sadae
[TITL]:Positron Trapping Defects in Neutron-Irradiated Vitreous and
Crystalline SiO[2]
[SOUR]:Mater. Sci. Forum, 255-257 (1997), 460-462
[LAB ]:(2); Hasegawa; Nippon Steel Co.; Univ. of Tokyo; Yamasada
[ABST]:Two types of positron-trapping defects have been found to from in
silica glass (v-SiO[2]) by fast-neutron irradiation: type-I and type-II
defects. The type-I defects give positron lifetime of about 0.3ns,
while the type-II defects provide 0.5ns. Very similar lifetime
components also appear in crystalline alpha-quartz (c-SiO[2]) after
irradiation, which suggests that the two types of positron-trapping
defects are common in v-SiO[2] and c-SiO[2]. The detailed annealing and
photo-quenching studies of positron annihilation and ESR for these two
types of defects suggest that the type-I defects are NBOHC
(non-bridging oxygen hole centers), while the type-II defects are Si
vacancies which can not be detected by ESR. Higher dose irradiation
than 1.0@times@10]20[ n/cm]2[ causes c-SiO[2] to change to metamict
(vitreous) phase (m-SiO[2]). Positronium atoms are found to from in
microvoids with average radii of about 0.3nm in v-SiO[2] and m-SiO[2].
This suggests that the microvoids are intrinsic structural open spaces
and reflect the topologically disordered structure of these phases in
subnanometer scale.
[TYPE]:Refractory Materials and Ceramics
[PROP]:positron annihilation, ESR, silica glass, quartz, irradiation effects,
metamictization
******************************************************************************
[ID ]:KL97-114
[AUTH]:Watanabe Yousuke, Sakai Akira and Sakurai Toshio
[TITL]:Lattice Parameter and Thermal Expansion Measurements of a LiF(001)
Surface by He-Atom Beam Diffraction Method
[SOUR]:J. Phys. Soc. Jpn., 66[3] (1997), 649-652
[LAB ]:(2); Sakurai; Kyoto Univ.
[ABST]:A new method for determining the lattice parameter using atomic beam
diffraction is described. Using this method, we have measured the
temperature dependence of the lattice parameter of LiF(001). It was
found that the value of the surface thermal expansion coefficient is
higher by a factor of 3.6 than the bulk value for temperatures up to
180Ž.
[TYPE]:Refractory Materials and Ceramics
[PROP]:LiF, surface, atom-beam diffraction
******************************************************************************
[ID ]:KL97-115
[AUTH]:Zhang Lian Meng, Hirai Toshio, Kumakawa Akinaga and Yuan Run Zhang
[TITL]:Cyclic Thermal Shock Resistance of TiC/Ni[3]Al FGMs
[SOUR]:Composites, 28B[1-2] (1997), 21-27
[LAB ]:(2); Hirai; Kakuda Res. Center, National Aerospace Lab.; Inst. for Adv.
Mater. Res., Wuhan Univ. of Technol.
[ABST]:Cyclic thermal shock tests on three TiC/Ni[3]Al FGM specimens were
carried out under simulated large-temperature-difference conditions.
The effective thermal conductivity was measured and the variation of
microstructure was observed. The effects of the sample geometry and the
TiC side surface state on the cyclic thermal shock behavior were
investigated, together with thermal stresses under steady-heating
conditions. The relation between the variation of effective thermal
conductivity and crack propagation was also investigated. The damage
which occurred in these FGMs was mainly caused by excessive inplane
compressive stresses on the surface of the TiC side during the cyclic
thermal shock test.
[TYPE]:Refractory Materials and Ceramics
[PROP]:cyclic thermal shock, TiC/Ni[3]Al, functionally graded materials
******************************************************************************
[ID ]:KL97-116
[AUTH]:Goto Takashi and Hirai Toshio
[TITL]:High-Temperature Oxidation Behavior of CVD Silicon Carbide and Iridium
Metal (in Japanese)
[SOUR]:Proc. 8th Symp. High-Performance Materials for Severe Environments,
(1997), 367-375
[LAB ]:(3); Hirai
[ABST]:It is a great issue for C/C composites to protect the surface from the
oxidation at high temperatures. CVD SiC and iridium metal films are
expected as candidate for these coating materials. Even if C/C
composites are well coated with these materials, the oxidation may not
be completely prevented, then the local oxidation of C/C composites
causes the CO[2] gas formation. Therefore, it is necessary to study the
oxidation behavior of CVD SiC and iridium metal in a CO[2] atmosphere
at high temperatures. In the present work, the oxidation kinetics of
CVD SiC and iridium metal was studied up to 2050K in CO[2] partial
pressures of 25kPa to 0.1MPa. The oxidation of CVD SiC proceeded
parabolically at every P[CO2] at less than 1950K. The activation energy
of the oxidation was about 400kJ/mol. At around 2000K, the mass gain
was parabolically, accompanying SiO[2] bubble formation. At more than
2000K, the bubble formation caused significant rapid mass gain and
succeeding partial mass loss. In the oxidation of iridium metal, a
linear mass loss was observed. The relationship between oxidation rates
(k[1b]) and P[CO2] was k[1b] propto P[O2]]3/2[. This suggests the
evaporation species should be IrO[3](gas).
[TYPE]:Refractory Materials and Ceramics
[PROP]:silicon carbide, iridium, high-temperature oxidation, thermogvauimetry,
CO[2] atmosphere
******************************************************************************
[ID ]:KL97-117
[AUTH]:Goto Takashi, Li Jianhui and Hirai Toshio
[TITL]:Preparation of B[4]C-TiB[2] System Composites by Arc Melting and Their
Thermoelectric Properties (in Japanese)
[SOUR]:Funtai oyobi Funmatsu Yakin (J. Jpn. Soc. Powder Powder Metall.), 44
(1997), 60-64
[LAB ]:(3); Hirai
[ABST]:B[4]C-TiB[2] quasi-binary composites were prepared by arc melting in
argon atmosphere using B[4]C and TiB[2] powders. Uniform lamella
texture indicating eutectic reaction was observed at 25mol%TiB[2] in
the quasi-binary system. The electrical conductivity of the
B[4]C-TiB[2] composites significantly increased with increasing TiB[2]
content. The thermal conductivity (kappa) of the composites containing
2mol%TiB[2] was slightly smaller than that of B[4]C, but the kappa
values increased with increasing TiB[2] content at more than 6mol%. The
Seebeck coefficient of B[4]C-TiB[2] composites showed maxima at
6mol%TiB[2]. The thermoelectric figure- of-merit (Z) values
exponentially increased with increasing temperature, showing maxima at
6mol%TiB[2]. The greatest ZT values obtained in the present study was
0.55 at T=1100K for the composite containing 6mol%TiB[2].
[TYPE]:Refractory Materials and Ceramics
[PROP]:boron carbide, titan boride, arc-melting, thermoelectric properties
******************************************************************************
[ID ]:KL97-118
[AUTH]:Goto Takashi, Li Jianhui, Hirai Toshio, Maeda Yukio, Kato Ryozo and
Maesono Akikazu
[TITL]:Rapid Measurement of Seebeck Coefficient by an AC Method (in Japanese)
[SOUR]:Funtai oyobi Funmatsu Yakin (J. Jpn. Soc. Powder Powder Metall.), 44
(1997), 65-69
[LAB ]:(2); Hirai; Sinku-Riko
[ABST]:An ac method for the measurement of the Seebeck coefficient was
developed. Specimens were heated periodically at frequencies in the
range 0.2-10 Hz using a semiconductor laser. The small temperature
increase and the resultant thermoelectric power were measured with a
Pt-Pt13% Rh thermocouple (25mu@m in diameter) through a lock-in
amplifier. The Seebeck coefficient of a Pt[90]Rh[10]foil measured by
the ac method was in agreement with that obtained from the standard
table. The optimum frequency and specimen thickness for the ac method
were 0.2 Hz and 0.1-0.2mm, respectively. The Seebeck coefficients of
silicon single crystal and several thermoelectric semiconductors
(Si[80]Ge[20], PbTe, FeSi[2], SiB[14]) measured by the ac method agreed
with those measured by a conventional dc method in the temperature
range between room temperature and 1200K. The time needed for each
measurement was less than a few tens of minutes, significantly shorter
than that for a conventional dc method.
[TYPE]:Refractory Materials and Ceramics
[PROP]:ac method, Seebeck coefficient, rapid measurement, thermoelectric
******************************************************************************
[ID ]:KL97-119
[AUTH]:Hirai Toshio, Goto Takashi and Sasaki Makoto
[TITL]:Functionally Graded Materials for Severe Environments (in Japanese)
[SOUR]:Proc. 8th Symp. High-Performance Materials for Severe Environments,
(1997), 35-39
[LAB ]:(2); Hirai; Faculty of Eng., Muroran Inst. of Technol.
[ABST]:Functionally Graded Materials (FGMs) have been proposed as thermal
barrier materials at high temperatures and under severe environments.
History and concept of FGMs are reviewed. Applications of FGMs to
aerospace and thermochemical cell are introduced.
[TYPE]:Refractory Materials and Ceramics
[PROP]:functionally graded materials, severe environment, thermal shock,
high-temperature oxidation
******************************************************************************
[ID ]:KL97-120
[AUTH]:Shishido Toetsu, Zheng Yutong, Saito Akihiro, Horiuchi Hiroyuki, Okada
Shigeru, Kudou Kunio and Fukuda Tsuguo
[TITL]:Synthesis and Properties of the RGaO[3] by Arc-Melting Method and
Comparison with the Data for RAlO[3] (in Japanese)
[SOUR]:Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi (J. Ceram. Soc. Jpn.),
105[8] (1997), 681-686
[LAB ]:(1); Fukuda; Mineralogical Inst., Faculty of Sci., The Univ. of Tokyo;
Faculty of Eng., Kanagawa Univ.
[ABST]:Synthesis of perovskite-type RGaO[3] was attempted by the arc-melting
method and compared with the data for RAlO[3]. RGaO[3] were obtained
only for R=La to Nd, however, those of RAlO[3] were obtained widely for
R=La to Tm. These regions are discussed from a view point of tolerance
factor, t. The formation range of perovskite-type compound is limited
to t=0.95 both for RGaO[3] and RalO[3] by this synthetic method. Garnet
phase was mainly obtained for R=Sm to Lu. CeGaO[3] is crystallized in
tetragonal structure with lattice parameters of alpha=0.3873(1)nm,
c=0.3880(1)nm (space group: P4/mmm), which is different from cubic as
reported in literatures. CeGaO[3] is completely decomposed into
starting materials by heating in air up to 1300Ž. The crystal
structure and thermochemical behavior of CeGaO[3] were essentially the
same as those of CeAlO[3].
[TYPE]:Refractory Materials and Ceramics
[PROP]:RMO[3](M=Ga,Al), Perovskite-type compound, arc-melting synthesis,
TG-DTA, tolerance factor
******************************************************************************
[ID ]:KL97-121
[AUTH]:Kuroda Noritaka, Wakabayashi Yusuke, Nishida Masato, Wakabayashi
Nobuyoshi, Yamashita Masahiro and Matsushita Nobuyuki
[TITL]:Decay Kinetics of Long-Lived Photogenerated Kinks in an MX Chain
Compound
[SOUR]:Phys. Rev. Lett., 79[13] (1997), 2510-2513
[LAB ]:(1); Yao; Keio Univ.; Nagoya Univ.;The Univ. of Tokyo
[ABST]:The time evolution of the thermal bleaching of the long-lived,
photogenerated midgap absorption band in a PtCl chain compound is
examined in a temperature range 220-330K. The long-lived absorption
arises from kinks each confined in a segment of the PtCl chain by
energy barriers of the order of 0.5eV. Because of a random distribution
of the barrier height the pair coalescence decay shows a ln t
dependence at all temperatures in the experimental range, 0-60 min, of
time t after discontinuation of laser pumping.
[TYPE]:Organic Materials
[PROP]:MX chain compound, photogenerated kinks, pair coalescence, diffusion
motion
******************************************************************************
[ID ]:KL97-122
[AUTH]:Ono Syuichi, Mori Takehiko, Endo Satoshi, Toyota Naoki, Sasaki
Takahiko, Watanabe Yousuke and Fukase Tetsuo
[TITL]:Temperature Dependence of the Electronic Structure of
$alpha-(BEDT-TTF)[2]MHg(SCN)[4](M=NH[4],K,Rb)
[SOUR]:Physica C, 290 (1997), 49-56
[LAB ]:(2); Dept. of Organic and Polymeric Mater., Tokyo Inst. of Technol.;
Res. Inst. for Adv. Sci. and Technol., Osaka Prefecture Univ.; Fukase;
Sakurai
[ABST]:By using the reported temperature dependence of the lattice constants
for organic metals alpha-(BEDT-TTF)[2]MHg(SCN)[4] (M=NH[4], K, Rb),
where BEDT-TTF is bis(ethylenedithio)tetrathia fulvalene, the
temperature dependence of the transfer integrals have been calculated.
In addition the derivatives of each transfer integral with respect to
each lattice constant are calculated. The transfer integrals are
sensitive to the change of the lattice constants within the conducting
sheet. The gap between the open and closed orbits in the momentum space
is principally generated by the difference of the transfer integrals,
c1 and c2; the magnitude of the intrastack dimerization the separation
between the open and closed orbits. Among the various salts, the NH[4]
salt shows an exceptionally large shrinkage of the lattice constant c,
which gives rise to large c1-c2, a large gap, and results in a
comparatively small cross section of the closed Fermi surface.
[TYPE]:Organic Materials
[PROP]:organic conductor, band structure, lattice parameter
******************************************************************************
[ID ]:KL97-123
[AUTH]:Sun Xin, Ma Y.
[TITL]:Electron Interaction and Soliton Energy in Conjugated Polymer
[SOUR]:Synth. Met., 85 (1997), 1035-1036
[LAB ]:(2); Dept. of Phys., Fudan Univ.; Kawazoe
[ABST]:The effect of e-e interaction on the creation energy of soliton in
polymer has been extensively studied by using the Hub-bard model.
However, the polymer possesses wide bandwidth, which is even larger
than the on-site repulsion U, then it can't be guaranteed that the
Hubbard model is always suitable, since this model originates from the
systems with narrow band. Actually the Hubbard model only contains the
diagonal part of e-e interaction, for wide band system, the
off-diagonal part of e-e interaction may have substantial impact. This
paper goes beyond the Hubbard model by using a screened Coulomb
interaction, which includes both diagonal and off-diagonal parts. Our
calculation shows that the effect of e-e interaction on the creation
energy of soliton is distinctly different from the result based on the
Hubbard model, the physical reason cause this difference is analysed.
[TYPE]:Organic Materials
[PROP]:polyacetylene, semi-empirical model, manybody and quasiparticle
theories, Hubbard model
******************************************************************************
[ID ]:KL97-124
[AUTH]:Wu Chang Qin, Fu Rong Tang, Li Zhi Qiang and Kawazoe Yoshiyuki
[TITL]:An Ab Initio Approach to Phonon Spectrum of Trans-Polyacetylene
[SOUR]:J. Phys.: Condens. Matter, 9[24] (1997), L351-L354
[LAB ]:(2); Dept. of Phys., Fudan Univ.; Kawazoe
[ABST]:By an ab inittio calculation based on the local density approximation
of density-functional theory, the force constants up to the third
nearest-neighbor carbon-hydrogen unit are determined to obtain the
phonon spectrum of trans-polyacetlene for the first time. The
calculated phonon frequencies at the Gamma point coincide well with
those of the observed infrared and Raman spectra of
trans-polyacetylene. The motion of hydrogen atoms is shown to be
important in determining the phonon spectrum of polyacetylene due to
the contribution of the bending between the CH and CC bonds.
[TYPE]:Organic Materials
[PROP]:trans-polyacetylene, local density approximation, IR spectrum, Raman
spectrum
******************************************************************************
[ID ]:KL97-125
[AUTH]:Itoh Kikuo, Yuyama Michinari, Kiyoshi Tsukasa, Takeuchi Takao, Inoue
Kiyoshi, Maeda Hiroshi, Miyatake Takayuki and Shimada Masao
[TITL]:Development of NbTi and Nb[3]Sn Conductors for 1 GHz NMR Spectrometer
[SOUR]:Proc. 16th Int. Cryogenic Engineering Conf. / Int. Cryogenic Materials
Conf., ed. by T. Haruyama, et al., Kitakyushu, 1996, (1997), 1735-1738
[LAB ]:(2); Tsukuba Magn. Lab., National Res. Inst. for Met.; Maeda;
Electronics Res. Lab., Kobe Steel, Ltd.
[ABST]:To meet the requirements for the outer magnet of the 1GHz NMR
spectrometer, which is being developed at Tsukuba Magnet Laboratories,
we have developed two Nb[3]Sn and a NbTi superconductors. Nb[3]Sn
conductors, fabricated using a composite of Nb-7.5wt%Ta filaments and
Cu-14wt%Sn-0.3wt%Ti matrix showed superior overall-Jc's at high
magnetic fields and 1.8K without deterioration of n values and RRR.
Improvement of 0.2% yield strength of a Nb[3]Sn conductor was achieved
by a Ta reinforcer incorporated in the conductor. As well, 0.2% yield
strength of NbTi conductor was improved by applying additional rolling
process after insulation coating, without spoiling dielectric break
down voltage of insulator. Those conductors developed showed superior
characteristics exceeding the target values and were found to be
feasible as conductors for the 1GHz NMR spectrometer.
[TYPE]:Biomaterials
[PROP]:NbTi conductor, Nb[3]Sn conductor, multi filament, high yield strength,
1 GHz NMR spectrometer
******************************************************************************
[ID ]:KL97-126
[AUTH]:Sasaki Yuji C, Yasuda Kenji, Suzuki Yoshio, Ishibashi Tadashi, Satoh
Isamu, Fujiki Yasutake and Ishiwata Shin'ichi
[TITL]:Two-Dimensional Arrangement of a Functional Protein by Cysteine-Gold
Interaction: Enzyme Activity and Characterization of a Protein
Monolayer on a Gold Substrate
[SOUR]:Biophys. J., 72[4] (1997), 1842-1848
[LAB ]:(2); Adv. Res. Lab., Hitachi Ltd.; Alpha; Dept. of Phys., School of
Sci. and Eng., and Adv. Res. Inst. for Sci. and Eng., Waseda Univ.
[ABST]:We have characterized the functional protein, myosin subfragment 1
(S1), attached to a gold substrate by the sulfhydryl groups of cysteine
in proteins. The amino groups of the regulatory light chain (RLC)
isolated from myosin were labeled with a radioisotope (]125[l), and the
labeled RLC was incorporated into S1 from which the RLC had been
removed. The radiation from ]125[l showed that S1 molecules had
attached to the gold and, through the interference effect of the
monochromatic radiation from ]125[l, provided information about the
position of labeled RLC sites in the S1 monolayer. The interference
fringes showed that the RLC was located close to the gold surface and
that all of the absorbed S1 molecules had the same orientation. We
confirmed that the motor function of S1 on the gold surface is
maintained by observing sliding movement at low ionic strength and by
observing the detachment at high ionic strength of fluorescent actin
filaments in the presence of ATP. We also found that the absorbed S1
molecules were not removed from the Au surface by a reducing agent.
Thus the Au-S bound is more stable than the S-S bond.
[TYPE]:Biomaterials
[PROP]:protein monolayer, cystein-gold interaction, interference patterns from
radioisotops
******************************************************************************
[ID ]:KL97-127
[AUTH]:Sazaki Gen, Yoshida Eriko, Komatsu Hiroshi, Nakada Toshitaka, Miyashita
Satoru and Watanabe Kazuo
[TITL]:Effects of a Magnetic Field on the Nucleation and Growth of Protein
Crystals
[SOUR]:J. Cryst. Growth, 173[1-2] (1997), 231-234
[LAB ]:(2); Komatsu; HFLSM
[ABST]:Crystallization of hen egg-white lysozyme and horse-spleen ferritin was
carried out under a steady and uniform magnetic field of 10T and
compared with the crystals grown under 0T. It is clearly demonstrated
that a magnetic field reduced the number of nuclei and not only
oriented the crystals but also modified the habit of protein crystals.
The present experimental result indicates that application of a
magnetic field is an efficient method for growing a small number of
large crystals.
[TYPE]:Biomaterials
[PROP]:crystal, protein, magnetic field, crystal growth
******************************************************************************
[ID ]:KL97-128
[AUTH]:Asami Katsuhiko, Ohnuma Shigehiro and Masumoto Tsuyoshi
[TITL]:XPS Characterization of High Electrical Resistance Soft Magnetic Thin
Co-Al-N Films
[SOUR]:ECASIA97: Proc. 7th Eur. Conf. Application of Surface and Interface
Analysis, ed. by I. Olefjord, et al., (1997), 609-612
[LAB ]:(1); LDRAM; Inst. Elec. Magn. Mater.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:Co-Al-N, thin film, surface analysis, XPS
******************************************************************************
[ID ]:KL97-129
[AUTH]:Chiba Hiroshi, Atou Toshiyuki and Syono Yasuhiko
[TITL]:Magnetic and Electrical Properties of Bi[1-x]Sr[x]MnO[3]: Hole-Doping
Effect on Ferromagnetic Perovskite BiMnO[3]
[SOUR]:J. Solid State Chem., 132[1] (1997), 139-143
[LAB ]:(3); Syono
[ABST]:Although La]3+[ and Bi]3+[ ions have similar ionic radii, the
Bi[1-x]Sr[x] MnO[3] system was found to show quite different behavior
from La[1-x]Sr[x]MnO[3] in which ferromagnetism with metallic
conductivity is achieved by the gdouble exchange mechanism." BiMnO[3]
which was synthesized under high pressure is a ferromagnetic insulator
with T[c]=105K, in contrast to antiferromagnetic LaMnO[3]. Though Sr
substitution in BiMnO[3] increased conductivity, no metallic state was
achieved up to the solid solution limit of x=0.67. Furthermore the
saturation magnetic moment of 3.6mu[B] observed in BiMnO[3] decreased
very rapidly with increasing x, and ferromagnetism disappeared for
x]0.4. These observations suggest that the highly polarizable Bi]3+[
ion with 6s]2[ lone pair would cause local distortion of the perovskite
lattice, which presumably reduces the mobility of carriers. The origin
of ferromagnetism in BiMnO[3] requires a mechanism other than the
double exchange theory.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:BiMnO[3], high-pressure synthesis, ferromagnetism, Perovskite
******************************************************************************
[ID ]:KL97-130
[AUTH]:Fujishiro Hiroyuki, Ikebe Manabu, Konno Yoshiyuki and Fukase Tetsuo
[TITL]:Sound Velocity Anomaly Associated with Polaron Ordering in
La[1-x]Sr[x]MnO[3]
[SOUR]:J. Phys. Soc. Jpn., 66[12] (1997), 3703-3705
[LAB ]:(1); Iwate Univ.; Fukase
[ABST]:The sound velocity nu[s](T) and the electrical resistivity rho(T) of
La[1-x]Sr[X]MnO[3] (0.11 leq X leq 0.17) have been measured and
anomalies in nu[s](T), which are related to the polaron-ordered phase
centered at X=1/8, have been observed. The phase diagram between the
polaron-ordering temperature T[p] and X has been determined from the
nu[s] anomalies.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:La[1-x]Sr[x]MnO[3], sound velocity, ferromagnetic order
******************************************************************************
[ID ]:KL97-131
[AUTH]:Hihara Takehiko, Sumiyama Kenji, Onodera Hideya, Wakoh Kimio and Suzuki
Kenji
[TITL]:Magnetism and Magnetoresistance in Fe/Cu Granular Films Produced by
Sputter Deposition and Subsequent Annealing
[SOUR]:J. Phys. Soc. Jpn., 66[6] (1997), 1785-1791
[LAB ]:(1); Suzuki; Yamayasu; Gijutsu
[ABST]:Magnetic properties and magnetoresistance (MR) have been studied in
homogeneous and granular Fe[x]Cu[100-x] films produced by sputter
(SP)-deposition and subsequent annealing. Concentration dependence of
the MR ratio a maximum at x=20 in the as-SP-deposited films. On the
other hand, it shows a monotonic change (no maximum) after annealed at
673K for 30min. Such an MR variation by annealing is ascribed to the
magnetic transition of Fe clusters in Cu matrices. Mossbauer spectra
and thermomagnetic curves observed at low temperatures indicate that
the as-SP-deposited Fe[x]Cu[100-x] alloy films are f.c.c for x[35 being
spin-glass, while those ones annealed at 673K for 30 min are f.c.c and
b.c.c mixture, being a spin-glass and ferromagnetic complex for x=11
and an antiferromagnetic and ferromagnetic one for X=20.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:iron-copper, granular material, sputter deposition, magnetoresistance,
Mossbauer effect
******************************************************************************
[ID ]:KL97-132
[AUTH]:Kanomata Takeshi, Ise Yasuhiro, Kumagai Nami, Haga Akira, Kamishima
Kenji, Goto Tsuneaki, Kimura Hisa Michi, Yoshida Hajime, Kaneko
Takejiro and Inoue Akihisa
[TITL]:Magnetovolume Effect of Co[2]B
[SOUR]:J. Alloys Compd., 259 (1997), L1-L4
[LAB ]:(1); Tohoku Gakuin Univ.; Inst. for Solid State Phys., Univ. of Tokyo;
LDRAM; Fujimori; Inoue
[ABST]:The effect of pressure on the Curie temperature T[c] and the saturation
magnetization sigma[s] at 4.2K for Co[2]B are investigated. T[c]
decreases linearly with pressure. The value of partial T[c] / partial p
is -1.1K kbar]-1[. The spontaneous magnetization at 4.2K is independent
of pressure. Furthermore, a positive spontaneous magnetostriction is
observed only for the lattice parameter c.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:cobalt boride, magnetic properties, pressure effect, thermal expansion
******************************************************************************
[ID ]:KL97-133
[AUTH]:Kaya Kiyoshi, Takahashi Hiroshi, Shibata Yoshihiko, Kanno Yasuhito and
Hirai Toshio
[TITL]:Experimental Surface Acoustic Wave Properties of AlN Thin Films on
Sapphire Substrates
[SOUR]:Jpn. J. Appl. Phys., 36 (1997), 307-312
[LAB ]:(2); Electronics Mater. and Devices Lab., Asahi Chemical Industry Co.,
Ltd.; Hirai
[ABST]:Equivalent circuit model parameters of Rayleigh propagation along the
[001] axis of AlN(110) thin films synthesized using chemical vapor
deposition on a sapphire R-plane were measured. The electro-mechanical
coupling constant was 0.63% at kh geqq 2, and the static capacitance
was 46.3pF/m in the case that the line/space ratio was unity. The
acoustic impedance and the normalized susceptance were obtained as a
function of wavelength of surface acoustic wave for various line/space
ratios.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:AlN, surface acoustic wave property, piezoelectricity, chemical vapor
deposition
******************************************************************************
[ID ]:KL97-134
[AUTH]:Kimura Hideo, Numazawa Takenori, Sato Mitsunori, Ikeya Tomonori, Fukuda
Tsuguo and Fujioka Koji
[TITL]:Crystal Axis Dependence of Magneto-Thermal Properties in RAlO[3] (R:
Dy, Ho and Er) Single Crystals Using for Magnetic Refrigeration
[SOUR]:Proc. 16th Int. Cryogenic Engineering Conf. / Int. Cryogenic Materials
Conf., ed. by T. Haruyama, et al., Kitakyushu, 1996, (1997), 2069-2072
[LAB ]:(1); National Res. Inst. for Met.; Fukuda; Daido Hoxan Inc.
[ABST]:Magnetization of RalO[3] (R:Dy, Ho and Er) single crystals along a-, b-
and c-axes has been measured by the SQUID magnetometer in the
paramagnetic temperature region. Single crystals were grown by the
Czochralski method. On the basis of the values of the magnetization,
magnetic entropy change was estimated depending on the crystal axis
direction. DyAlO[3] single crystal using along b-axis and ErAlO[3]
along c-axis are promising materials for the magnetic refrigerants
using the Carnot cycle in the temperature range between 4.2 and 20K.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:magneto-thermal property, RAlO[3] (R: Dy, Ho and Er), magnetic
property, rare earth, orthoaluminate, magnetic entropy
******************************************************************************
[ID ]:KL97-135
[AUTH]:Lim Sang Ho, Choi Y.S, Han S.H, Kim H.J
[TITL]:Magnetostriction of Tb-Fe-(B) Thin Films Fabricated by RF Magnetron
Sputtering
[SOUR]:IEEE Trans. Magn., 33[5] (1997), 3940-3942
[LAB ]:(2); Korea Inst. of Sci. and Technol.; Hankook Core Co., Ltd.; Fujimori
[ABST]:The magnetostriction of TbFe and TbFeB thin films is systematically
investigated over a wide composition range from 40.2 to 68.1at.% Tb for
the B-free alloys and from 44.1 to 66.6at.% Tb for the B containing
thin films. The films were fabricated by rf magnetron sputtering. The
microstructure mainly consists of an amorphous phase at low Tb contents
and, at high Tb contents, a mixture of an amorphous phase and an alpha
Tb phase. Excellent magnetostrictive characteristics, particularly at
low magnetic fields, are achieved in both TbFe and TbFeB thin films;
for example, a magnetostriction of 138ppm is obtained in a TbFeB thin
film at a magnetic field as low as 30 Oe. These excellent
magnetostrictive properties of the present thin films are supported by
the excellent magnetic softness, the coercivity below 10 Oe and a
typical squared-loop shape with the saturation field as low as 1kOe. It
is considered that, due to the excellent low field as low as 1kOe. It
is considered that, due to the excellent low field magnetostrictive
characteristics, the present TbFe based magnetostrictive thin films are
suitable for Si based microdevices.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:Tb-Fe alloys, B addition, magnetostriction, thin films, magnetic
materials
******************************************************************************
[ID ]:KL97-136
[AUTH]:Makino Akihiro, Bitoh Teruo, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Nanocrystalline Fe-M-B-Cu (M=Zr, Nb) Alloys with Improved Soft Magnetic
Properties
[SOUR]:J. Appl. Phys., 81[6] (1997), 2736-2739
[LAB ]:(2); Alps Co.; Inoue; Res. Inst. for Electric and Magn. Mater.
[ABST]:The soft magnetic properties of the nanocrystalline Fe-M-B (M=Zr,Nb)
alloys, which exhibit a high saturation flux density (B[s]) above 1.5T
as well as a high effective permeability (mu[e]) above 30000 at 1kHz,
were found to be improved by adding small amounts of Cu and by
optimizing the chemical composition. The addition of Cu to the alloys
decreases the bcc grain size. The excellent soft magnetic properties (a
high mu[e] of 100000 at 1kHz combined with a high B[s] of 1.53T) can be
achieved in the region where small grain size, as well as nearly
zero-magnetostriction are obtained, which is attained in the
compositional range around Fe[84]Nb[3.5]Zr[3.5]B[8]Cu[1]. The soft
magnetic properties can be further improved by low temperature
annealing before the crystallization treatment, probably as a result of
a decreased grain size distribution in the crystallized state.
Consequently, the mu[e] reaches the maximum value of 120000 for the
nanocrystalline Fe[84]Nb[3.5]Zr[3.5]B[8]Cu[1] alloy.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:nanocrystalline alloy, iron-based system, soft magnetic property,
nanocrystallization, high permeability
******************************************************************************
[ID ]:KL97-137
[AUTH]:Makino Akihiro, Hatanai Takashi, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Nanocrystalline Soft Magnetic Fe-M-B(M=Zr, Hf, Nb) Alloys and Their
Applications
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 594-602
[LAB ]:(2); Alps. Co.; Inoue; Res. Inst. for Electric and Magn. Mater.
[ABST]:This paper reviews our results on the development of a new type of soft
magnetic material with high saturation magnetic flux density (Bs) above
1.5T as well as excellent soft magnetic properties. A mostly single bcc
structure composed of alpha-Fe grains with about 10-20nm in size
surrounded by a small amount of an intergranular amorphous layer was
obtained by crystallization of amorphous alloys prepared by
melt-spinning technique. The typical nanocrystalline bcc
Fe[90]Zr[7]B[3], Fe[89]Hf[7]B[4] and Fe[84]Nb[7]B[9] ternary alloys
subjected to the optimum annealing exhibit high Bs above 1.5T as well
as high effective permeability (mu e) at 1 kHz above 20000. Excellent
soft magnetic properties of the nanocrystalline Fe-M-B based alloys can
be obtained by the decrease in the bcc grain size, magnetostriction
(lambda) and the increase in Tc of the intergranular amorphous phase by
optimizing the crystallization process, chemical composition and adding
small amounts of elements. For example, the improved FeZrNbBCu alloy
shows the high mu e of 160000 combined with the high Bs of 1.57T. This
excellent mu e is comparable to those of nanocrystalline
Fe[73.5]Si[13.5]B[9]Nb[3]Cu[1] and the zero-magnetostrictive Co based
amorphous alloys, and the high Bs is comparable to those of the Fe
based amorphous alloys with rather good soft magnetic properties. The
excellent characteristics of a power transformer, a common mode choke
coil, a pulse-transformer and a flux gate magnetic detector made of
'NANOPERM]TM[' were found in agreement with its very low core losses,
sufficient thermal stability and low stress-sensibility of magnetic
properties. The nanocrystalline Fe-M-B based alloys 'NANOPERM]TM[' is
therefore expected to by used for many kinds of magnetic parts and
devices.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:nanocrystalline alloy, malt-spun ribbon, soft magnetic property,
zero-magnetostriction, saturation magnetic flux density
******************************************************************************
[ID ]:KL97-138
[AUTH]:Makino Akihiro, Inoue Akihisa, Hatanai Takashi and Bitoh Teruo
[TITL]:Improved Soft Magnetic Properties of Nanocrystalline Fe-M-B-Cu (M=Zr,
Nb) Alloys with High Saturation Magnetic Flux Density and
Zero-Magnetostriction
[SOUR]:Mater. Sci. Forum, 235-238 (1997), 723-728
[LAB ]:(2); Central Res. Lab., Alps Co. Ltd.; Inoue
[ABST]:The compositional dependence and the annealing temperature dependence
of the soft magnetic properties for the nanocrystalline Fe-M-B-Cu(M=Nb,
Zr) alloys have been investigated. The high effective permeability,
mu[e], above 100,000 at 1 kHz combined with the high saturation
magnetic flux density, B[s], of 1.45 to 1.61T have been obtained in the
Fe[100-a-b-c-d]Nb[a]Zr[b]B[c]Cu[d] (3.25 leq a leq 3.5, b approx a, 6.5
leq c leq 8 and 1 leq d leq 2) alloys. These alloys consist of fine bcc
grains with less than 10nm in size and exhibit nearly or exactly
zero-magnetostriction. This excellent mu[e] value is comparable to
those of nanocrystalline Fe[73.5]Si[13.5]B[9]Nb[3]Cu[1] alloy and
zero-magnetostrictive Co based amorphous alloys, and the high B[s] is
comparable to those of Fe based amorphous alloys with good soft
magnetic properties. The nanocrystalline Fe-M-B based alloys with
excellent soft magnetic properties as well as high B[s] and
zero-magnetostriction are expected to be used for many kind of magnetic
parts and devices.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:nanocrystalline alloy, soft magnetic properties, permeability,
saturation magnetic flux density, zero-magnetostriction
******************************************************************************
[ID ]:KL97-139
[AUTH]:Momozawa Nobuyuki, Taguchi Yoshiaki, Nagao Yukinobu, Nishiyama
Katsuhiro, Abe Masahiko, Sakai Hideki, Matsumoto Mutsuyoshi and
Yamaguchi Yasuo
[TITL]:Neutron Diffraction Study of Pb-Substituted Hexagonal Ferrite
(Ba[0.2]Pb[0.8])[2]Zn[2]Fe[12]O[22]
[SOUR]:Zairyo Gijutsu (Jpn. Res. Inst. Mater. Technol.), 15[1] (1997), 20-24
[LAB ]:(2); Faculity of Industrial Sci. and Technol., Sci. Univ. of Tokyo;
Faculity of Sci. and Technol., Sci. Univ. of Tokyo; National Inst. of
Mater. and Chem. Res., Tsukuba; Yamayasu
[ABST]:Neutron diffraction experiments were carried out on single crystals of
Pb-substituted hexagonal ferrites (Ba[0.2]Pb[0.8])[2]Zn[2]Fe[12]O[22].
The diffraction patterns are characterized by the presence of magnetic
satellite reflections which split off from the nuclear reflections.
From the analysis of magnetic satellites, (Ba[0.2]Pb[0.8])[2]
Zn[2]Fe[12]O[22] can be concluded to take a helimagnetic structure with
the propagation vector along the c-axis.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:hexagonal ferrite, Pb ion, helimagnetic structure, neutron diffraction
******************************************************************************
[ID ]:KL97-140
[AUTH]:Niki Haruo, Tamaki Katsuji, Kano Kikuhiro, Shinohara Takeshi, Tomiyoshi
Shoichi, Omori Mamoru and Kajitani Tsuyoshi
[TITL]:Nuclear Relaxation of Hydrogen-Doped Antiferromagnetic
YBa[2]Cu[3]O[6+x]H[y]
[SOUR]:J. Phys. Soc. Jpn., 66[11] (1997), 3655-3659
[LAB ]:(1); Dept. of Phys., College of Sci., Univ. of the Ryukyus; Yamayasu;
Dept. of Mater. Sci. and Eng., Faculty of Eng., Ehime Univ.; Dept. of
Appl. Phys., Faculty of Eng., Tohoku Univ.
[ABST]:Cu(1) NQR, Cu(2) zero field NMR, and proton NMR have been measured in
the antiferro-magnetic (AF) phase of a powdered sample of
hydrogen-doped YBa[2]Cu[3]O[6.1]H[0.14] from 4.2 to 300K. The line
width of ]1[H NMR increases abruptly below 20K. The enhancements of
T[2]]-1[ and T[1]]-1[ of ]63[Cu(1) NQR occur around 20 and 40K,
respectively. The relaxation mechanism of T[1] of NQR changes at T[rm]
= 80K and the time dependence of its nuclear magnetization recovery
shows a nonexponential type for T[T[rm] and an exponential one for
T]T[rm]. The predominant source for T[1] below T[rm] is found to be the
fluctuating magnetic fields due to the staggered Cu]2+[ moments induced
by the hole doping effect. Above T[rm], T[1]]-1[ of NQR increases
gradually with temperature but it is almost temperature independent
above 150K, what can not be explained by the effect of the ordered AF
Cu]2+[ moments in theCu(2)O[2] plane and also by the Raman process of
the lattice vibrations.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:antiferromagnetic, high T[c] superconductor, ]1[H NMR, ]63[Cu NMR
******************************************************************************
[ID ]:KL97-141
[AUTH]:Numazawa Takenori, Kimura Hideo, Sato Mitsunori, Sato Akio, Shimamura
Kiyoshi and Fukuda Tsuguo
[TITL]:Magnetic Field Dependence of Thermal Conductivity in Rare-Earth Oxides
for Heat Switch Application
[SOUR]:Proc. 16th Int. Cryogenic Engineering Conf. / Int. Cryogenic Materials
Conf., ed. by T. Haruyama, et al., Kitakyushu, 1996, (1997), 2073-2076
[LAB ]:(1); Tsukuba Magn. Lab., National Res. Inst. for Met; Phys. Properties
Division, National Res. Inst. for Met.; Fukuda
[ABST]:The thermal conductivity of rare-earth oxides; Garnets,
Ortho-aluminates and Vanadates have been measured from 2K to 25K in the
magnetic fields of up to 5T. The thermal conductivity in zero magnetic
field shows a strong correlation with the rare-earth magnetic ion where
the phonon is scattered by the low lying energy levels. The peak value
of the thermal conductivity decreases in the order of rare-earth ions,
Gd, Er, Dr and Ho. The strong magnetic field dependence is observes in
Dy, Er and Ho oxides. A large thermal conductivity change by the
magnetic field is found in Dy oxides; it is reduced sim70 times in
Dy[3]Ga[5]O[12] crystal which will be useful as the heat switch.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:rare-earth, oxide, thermal conductivity, magnetic field, garnet,
aluminate, vanadate
******************************************************************************
[ID ]:KL97-142
[AUTH]:Odahara Hirotaka, Tomiyoshi Shouichi and Shinohara Takeshi
[TITL]:NMR Study on the Magnetic Properties and Phase Transformation of MnAl
Alloys
[SOUR]:Physica B, 237-238 (1997), 568-569
[LAB ]:(2); Faculty of Eng., Ehime Univ.; Yamayasu
[ABST]:Magnetic properties of the tau-, varepsilon- and mixed phases in MnAl
alloy and the formation mechanism of the tau-phase have been
investigated using pulsed NMR. For the antiferromagnetic epsilon-phase
a sharp resonance peak has been observed at 120MHz which is assigned to
the ]55[Mn nucleus. NMR resonance signals for the ferromagnetic
tau-phase have been observed at 200,170 and 100MHz which are assigned
to Mn atoms with different nearest-neighbor configurations and to the
Al atom. NMR peak intensities have changed sensitively depending on
heat treatments of the samples reflecting the phase transformation.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:MnAl, magnetic property, phase transformation, NMR
******************************************************************************
[ID ]:KL97-143
[AUTH]:Ohnuma Masato, Hono Kazuhiro, Abe Eiji, Onodera Hidehiro, Mitani Seiji
and Fujimori Hiroyasu
[TITL]:Microstructure of Co-Al-O Granular Thin Films
[SOUR]:J. Appl. Phys., 82[11] (1997), 5646-5652
[LAB ]:(1); National Res. Inst. for Met.; Fujimori
[ABST]:We have investigated the microstructures of Co-Al-O granular thin
films, which were prepared by the sputter-deposition technique with
various oxygen partial pressures. The constituent phases, grain sizes
of granular particles, and width of insulating channels have been
evaluated quantitatively. The specimen with he optimum giant
magnetoresistance (GMR) is composed of nanoscale Co particles, and
these are completely isolated by amorphous aluminum oxide channels. The
GMR behavior observed in the Co-Al-O films has a close correlation with
the width of the insulating channel and the grain size of the magnetic
particles, which is consistent with the spin-dependent tunneling
conduction mechanism of GMR.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:Co-Al-O, granular film, microstructure, transmission electron
microscope, giant magnetoresistance
******************************************************************************
[ID ]:KL97-144
[AUTH]:Ono Sachiko, Sakakibara Akira, Seki Tomonori, Osaka Tetsuya, Koiwa
Ichiro, Mita Juro, Iwabuchi Toshiyuki and Asami Katsuhiko
[TITL]:Correlation between Composition, Microstructure, and Ferroelectric
Properties of SrBi[2]Ta[2]O[9] Thin Films
[SOUR]:J. Electrochem. Soc., 144[7] (1997), L185-L187
[LAB ]:(2); Adv. Res. Inst. for Sci. and Eng., Waseda Univ.; Dept. of Appl.
Chem., School of Sci. and Eng., Kagami Memorial Lab. for Mater. Sci.
and Technol., Waseda Univ.; Oki Electric Industry Co. Ltd.; LDRAM
[ABST]:SrBi[2]Ta[2]O[9] thin films prepared by a solution-deposition process
were formed at various annealing temperatures. P-E hysteresis loops of
the films exhibited well-defined shapes, and the leakage current
decreased with increasing annealing temperature except for one annealed
at 750Ž. The considerable amount of metallic Bi on the film surface
diffused from the inner part was evaluated by a quantitative x-ray
photoelectron spectroscopic analysis. A discontinuity in morphology
such as cavities detected by transmission electron microscopic
observation at grain boundaries between large single-crystal grains and
microcrystallite regions, which was pronounced in the film annealed at
750Ž, is suggested as inducing in leakage current by the condensation
of metallic Bi at the cavities.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:SrBi[2]Ta[2]O[9], ferroelectrics, memory device, surface analysis, thin
film
******************************************************************************
[ID ]:KL97-145
[AUTH]:Peng Dong Liang, Konno Toyohiko J.
[TITL]:Structure and Magnetic Properties of Fe-Cr-N Sputter-Deposited Films
[SOUR]:J. Magn. Magn. Mater., 172[1-2] (1997), 41-52
[LAB ]:(1); Suzuki; Yamayasu
[ABST]:Structure and magnetic properties of Fe-Cr-N ternary films prepared by
DC magnetron facing-target sputtering have been investigated by X-ray
diffraction (XRD), scanning electron microscopy (SEM), transmission
electron microscopy(TEM), vibrating sample magnetometry (VSM) and
Mossbauer effect. These films exhibit perpendicular magnetic
anisotropy. We found that N[2]-to-Ar flow ratio, Fe-Cr target area
ratio and substrate temperature during film preparation are the factors
influencing the anisotropy. Adjusting the chemical composition and
deposition parameters, we obtained saturation magnetization of 300-400
emu/cm]3[ and perpendicular coercivity of 800-1100 Oe. XRD measurements
show that the films generally consist of the alpha-Fe(Cr) and
gamma'-(Fe, Cr)[4]N[x] (x[1) phases, and that the enhancement of
perpendicular anisotropy is always accompanied by a decrease in the
grain size of alpha-Fe(Cr) phase and growth of the gamma'-(Fe,
Cr)[4]N[x] phase with a pronounced (200) texture. The Mossbauer spectra
show that the gamma'-(Fe, Cr)[4]N[x] phase is nonmagnetic at room
temperature. Using the SEM and TEM, we found that the nonmagnetic
gamma'-(Fe, Cr)[4]N[x] phase displays columnar growth and that the
small ferromagnetic alpha-Fe(Cr) grains of about 2-20nm in diameter are
located at grain boundaries of gamma'-(Fe, Cr)[4]N[x] grains. Shape
anisotropy seems to play an important part in the perpendicular
magnetic anisotropy in these Fe-Cr-N films.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:Fe-Cr-N, nonequilibrium phase, magnetism, perpendicular magnetic
anisotropy, transmission electron micrograph
******************************************************************************
[ID ]:KL97-146
[AUTH]:Peng Dong Liang, Sumiyama Kenji, Konno Toyohiko J and Suzuki Kenji
[TITL]:Perpendicular Magnetic Anisotropy of Fe-Cr-N Films Prepared by DC
Reactive Sputtering
[SOUR]:Jpn. J. Appl. Phys., 36[4B] (1997), L479-L481
[LAB ]:(1); Suzuki
[ABST]:Fe-Cr-N ternary films prepared by DC magnetron facing-target sputtering
show perpendicular magnetic anisotropy. Upon appropriate adjustment of
the chemical composition and deposition parameters, saturation
magnetization of 0.37-0.5Wb/m]2[ (300-400emu/cm]3[) and perpendicular
coercivity of 6.4 times 10]4[ -8.8 times 10]4[ A/m (800-1100 Oe) are
detected in the Fe-Cr-N films. X-ray diffraction measurements reveal
that the films with large perpendicular anisotropy generally consist of
the fine-grain alpha-Fe(Cr) phase and the gamma'-(Fe, Cr)[4]N[x] (x[1)
phase having a pronounced (200) texture. By TEM observation, we found
that the nonmagnetic gamma'-(Fe, Cr)[4]N[x] phase displays columnar
growth and that the small ferromagnetic alpha-Fe(Cr) grains of about
2-20nm diameter are located at grain boundaries of
gamma'-(Fe,Cr)[4]N[x] grains in the Fe[71]Cr[20]N[9] film.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:iron-chromium-nitrogen, perpendicular magnetic anisotropy, DC reactive
sputtering, x-ray diffraction, transmission electron microscopy
******************************************************************************
[ID ]:KL97-147
[AUTH]:Shima Toshiyuki, Yokoyama Hiroyuki and Fujimori Hiroyasu
[TITL]:Magnetostriction and Magnetic Properties of Sm-Fe-B and Tb-Fe-B Thin
Films and Multilayers
[SOUR]:J. Alloys Compd., 258 (1997), 149-154
[LAB ]:(3); Fujimori
[ABST]:Magnetostriction and magnetic properties of amorphous Sm-Fe-B and
Tb-Fe-B thin films and Sm-Fe-B/Tb-Fe-B multilayers have been
investigated. From a systematic investigation on Sm-Fe-B alloy thin
films, it was found that the film with B content of 3.5at.% exhibits a
low coercivity of about 50 Oe and a large magnetostriction of about
-340 times 10]-6[ at 100 Oe. In the case of multilayers,
magnetostriction varies with the thickness ratio of the two layers. For
the magnetostriction of the multilayers it was found that the
magnetostriction is sensitively affected by Young's modulus, Poisson
ratio and the thickness of the constituent layers. The present result
may indicate that multilayering is a suitable route to achieve good
magnetic softness even in this kind of R-Fe thin film.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:magnetostriction, Sm-Fe-B alloy, Tb-Fe-B alloy, magnetic properties,
thin film
******************************************************************************
[ID ]:KL97-148
[AUTH]:Suzuki Kiyosaku, Cadogan John Michael, Sahajwalla Veena, Inoue Akihisa
and Masumoto Tsuyoshi
[TITL]:On the Nanostructural Formation Process in Fe-M-B (M=Zr or Nb) Soft
Magnetic Alloys
[SOUR]:Mater. Sci. Forum, 235-238 (1997), 765-770
[LAB ]:(2); School of Mater. Sci. and Eng., The Univ. of New South Wales,
Austraria; School of Phys., The Univ. of New South Wales, Austraria;
Inoue
[ABST]:The nano-structural formation kinetics in soft magnetic Fe[90]Zr[7]B[3]
and Fe[80]Nb[6]B[14] alloys have been investigated. The nanocrystallite
formation in the Fe-Zr-B alloy is governed mostly by a
nucleation-and-growth mechanism. On the other hand, the nano-structural
formation mechanism in the Fe-Nb-B alloy shows a change in the fraction
transformed range 0.1-0.2. The first- and second-stage nano-structural
formation processes have been described by the nucleation-and-growth
model with an Avrami exponent sim1.5 and the grain-growth model with a
grain-growth exponent of 1.5-3, respectively. This two-stage nature in
the nano-structural formation kinetics can be attributed to a high
population density of the primary bcc nuclei.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:crystallization, nanocrystalline soft magnetic alloys, grain growth,
Fe-Zr-B, Fe-Nb-B
******************************************************************************
[ID ]:KL97-149
[AUTH]:Tanaka Yasuhiro, Kimura Naomasa, Hono Kazuhiro, Yasuda Katsuhiko and
Sakurai Toshio
[TITL]:Microstructures and Magnetic Properties of Fe-Pt Permanent Magnets
[SOUR]:J. Magn. Magn. Mater., 170 (1997), 289-297
[LAB ]:(2); Nagasaki Univ. School of Dentistry; Honda R&D Co., Ltd.; National
Res. Inst. for Met.; Sakurai
[ABST]:We have investigated the magnetic properties of Fe-38.5Pt, Fe-39.5Pt
and Fe-50.0Pt(at%) alloys after various heat treatment conditions using
a vibrating sample magnetometer, and correlated these properties with
the microstructures of the alloys by transmission electron microscopy.
The Fe-50Pt alloy shows poor magnetic hardness regardless of the heat
treatment conditions. The magnetic hardness of the Fe-39.5Pt alloy
shows a maximum value after annealing for 10h at 873K, while it
monotonically decreases after annealing at 1073K. The alloy with the
highest coercivity was composed of a single phase gamma[1] with an
average domain size of approximately 10nm. The electron diffraction
results indicate that the alloy is frustrated with accumulated stress,
induced by a cubic rightarrow tetragonal transformation which occurs
without twinning. On the other hand, when stress is relieved by twin
formation after prolonged aging, the coercivity decreases. By annealing
at 1073K, the well known polytwin structure evolves. However, only poor
hard magnetic properties are observed when this polytwin structure
appears. Hence, the highest coercivity is attributed to the formation
of nanoscale L1[0] ordered antiphase domains which is expected to be a
highly anisotropic single domain magnetic particle.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:APFIM, Fe alloy, magnetic material
******************************************************************************
[ID ]:KL97-150
[AUTH]:Kobayashi Nobukiyo, Ohnuma Shigehiro, Masumoto Tsuyoshi, Mitani Seiji
and Fujimori Hiroyasu
[TITL]:Giant Magnetoresistance in (Fe, Co)-X-O (X=Y, Nd, Sm, Gd, Tb, Dy)
Nano-Granular Films (in Japanese)
[SOUR]:Nippon Oyo Jiki Gakkaishi (J. Magn. Soc. Jpn.), 21[4-2] (1997), 461-464
[LAB ]:(2); The Res. Inst. for Electric and Magn. Mater.; Fujimori
[ABST]:We studied the giant magnetoresistance (GMR) and related properties of
(Fe, Co)-X-O (X=Y, Nd, Sm, Gd, Tb, Dy) films. The films were prepared
by conventional rf sputtering of Fe, Co or Fe-Co, and X[2]O[3] targets.
The films seem to have a granular structure composed of nano-size
metallic grains and thin oxide boundaries. The films exhibited
superparamagnetic properties and high electrical resistivities of 10]4[
- 10]6[ mu Omega cm, and had negative and isotropic magnetoresistances
at room temperature. The values of Delta rho/rho[0] in Co-based films
were larger than those of Fe-based films, and a GMR effect of 2.7% at
500 Oe was observed for Co[51.0]Sm[10.7]O[38.3] film at room
temperature. The GMR effect observed in the granular structure is
attributed to spin-dependent tunneling conductance through a thin oxide
layer between grains in the film.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:(Fe, Co)-RE-O, granular film, giant magnetoresistance, high electrical
resistivity, sputtering
******************************************************************************
[ID ]:KL97-151
[AUTH]:Sugawara Takahiko, Takanashi Koki and Fujimori Hiroyasu
[TITL]:Annealing Effect on Giant Magnetoresistance in Sputtered Cu-Co Alloys
Films (in Japanese)
[SOUR]:Nippon Oyo Jiki Gakkaishi (J. Magn. Soc. Jpn.), 21[4-2] (1997), 469-472
[LAB ]:(3); Fujimori
[ABST]:We investigated the anneal effect on magnetoresistance (MR) in
Cu[100-x]Co[x] (x=10-40at%) alloy films. The samples were prepared by
rf-sputtering onto liquid-nitro-gen-cooled Si substrates, and annealed
at 500Ž for 10 min, 1h, and 10h. For x leq 20at%, we found GMR
behavior even in the as-deposited state. In other words, the
resistivity decreases as the applied field increases, and the change in
the resistivity is very large in high fields. The MR saturates more
easily, but the magnitude of MR is smaller on annealing. For x leq
30at%, on the other hand, the MR in the as-deposited state shows
anisotropic MR behavior, which is typical of a simple ferromagnetic
metal. The MR behavior changes to GMR on annealing.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:Cu-Co alloys, sputtering, magnetoresistance, annealing effect, phase
separation
******************************************************************************
[ID ]:KL97-152
[AUTH]:Wakoh Kimio, Yoshida Masanori, Konno Toyohiko J, Hihara Takehiko,
Sumiyama Kenji and Suzuki Kenji
[TITL]:Magnetic Properties and GMR in Fe-Cu Granular Films Prepared by Ionized
Cluster Beam Technique (in Japanese)
[SOUR]:Nippon Kinzoku Gakkaishi (J. Jpn. Inst. Met.), 61[6] (1997), 502-506
[LAB ]:(1); Gijutsu; Suzuki
[ABST]:Fe cluster dispersed Fe-Cu granular films have been produced by an
ionized cluster beam (ICB) technique. Magnetoresistance (MR) and
magnetic properties were observed for Fe-Cu films produced at different
acceleration voltages (V[a]=0 and 2.5kV). The chemical composition of
the films prepared at V[a]=2.5kV is Fe-richer than the designed one,
indicating the "resputtering" of Cu atoms from the deposited films.
These films exhibit giant magnetoresistance (GMR), which does not
saturate even at high fields: conduction-electrons suffer spin-disorder
scattering. With increasing Fe concentration, the MR values of granular
films monotonically decrease, whereas those of the sputtered and
thermally evaporated films show maxima at around 25at%Fe. The
disappearance of the MR maximum is ascribed to the presence of
antiferromagnetic Fe clusters. In addition, the MR values of the
ICB-deposited films prepared at V[a]=2.5kV are higher than those at
V[a]=0kV, indicating that the former is smaller in the average cluster
size than the latter.
[TYPE]:Magnetic Materials and Electronic Materials
[PROP]:iron-copper, granular material, magnetoresistance, ionized cluster
beam, acceleration voltage dependence
******************************************************************************
[ID ]:KL97-153
[AUTH]:Fukuda Kunihiro, Iwaki Genzo, Kimura Morio, Sakai Shuji, Iijima Yasuo,
Takeuchi Takao, Inoue Kiyoshi, Kobayashi Norio, Watanabe Kazuo and
Awaji Satoshi
[TITL]:Critical Current Density of Nb[3]Al Superconducting Wire for High Field
Magnet by Rapid-Quenching Process
[SOUR]:Proc. 16th Int. Cryogenic Engineering Conf. / Int. Cryogenic Materials
Conf., ed. by T. Haruyama, et al., Kitakyushu, 1996, (1997), 1669-1672
[LAB ]:(1); Hitachi Cable, Ltd.; Tsukuba Magnet Lab.; Kobayashi; HFLSM
[ABST]:Multifilamentary Nb[3]Al superconducting wires for high field magnets
above 20T have been developed by a rapid-quenching process. Nb/Al
composites fabricated by the jelly-roll process, which showed good
workability, were applied to a rapid-quenching process to ascertain the
J[c] properties. The highest J[c], 440A/mm[2] at 20T, was obtained as a
result. A wire of 1kilometer length was fabricated. Scattering of the
J[c] in the longitudinal direction was examined and found to be within
pm10%.
[TYPE]:Superconductors
[PROP]:Nb[3]Al, superconducting wire, critical current density, high magnetic
field
******************************************************************************
[ID ]:KL97-154
[AUTH]:Fukutomi Masao, Kumagai Shunji and Maeda Hiroshi
[TITL]:Fabrication of YBa[2]Cu[3]O[y] Thin Films on Textured Buffer Layers
Grown by Plasma Beam Assisted Deposition
[SOUR]:Aust. J. Phys., 50 (1997), 381-389
[LAB ]:(2); National Res. Inst. for Met., Tsukuba Lab.; Mitsuba Electric Mfg
Co. Ltd.; Maeda
[ABST]:A new technique named plasma beam assisted deposition (PBAD) is
proposed to grow in-plane textured yttria-stabilised zirconia (YSZ)
this films on polycrystalline metallic substrates as a buffer layer for
deposition of YBa[2]Cu[3]O[y](YBCO) films. The in-plane texturing of
the YBCO films obtained is decisively governed by that of the YSZ
buffer layer on which the YBCO grows. Because of a reduction of the
weak links at high-angle grain boundaries, a marked increase in the
critical current density J[c] is observed with improved texturing of
the YBCO films. So far, it has been demonstrated that YBCO films with
J[c] above 10]5[ A cm]-2[ (77K, 0T) can be successfully deposited by a
laser ablation technique. The PBAD process proposed here is found to be
valuable technologically because it offers a very convenient method to
grow textured films on long tape or large area substrates. An attempt
was also made to grow textured films simultaneously on one side or both
sides of various pieces of tape substrates. The results indicate that
PBAD is one potential technique for future large scale application of
YBCO films.
[TYPE]:Superconductors
[PROP]:YBCO thin film, YSZ buffer layer, plasma beam deposition, metallic
substrate, In-plane texture
******************************************************************************
[ID ]:KL97-155
[AUTH]:Harada Naoyuki, Fukuda Yuji, Ichikohara Hideki, Osaki Katashi, Tada
Naofumi, Sakai Syuji and Watanabe Kazuo
[TITL]:Superconducting Properties of Nb[3]Al by Reaction between sigma-phase
Nb[2]Al and Nb Powders
[SOUR]:Proc. 16th Int. Cryogenic Engineering Conf. / Int. Cryogenic Materials
Conf., ed. by T. Haruyama, et al., Kitakyushu, 1996, (1997), 1693-1696
[LAB ]:(1); Dept. Electrical and Electronics Eng., The Faculty of Eng.,
Yamaguchi Univ.; System's Mater. Lab., Hitachi-Cable Ltd.; HFLSM
[ABST]:Superconducting Nb[3]Al tapes were prepared by the powder metallurgy
method using the diffusion reaction between sigma-phase(Nb[2]Al) and Nb
powders. The external-heating and the ohmic-heating compared, to obtain
the stoichiometric composition of A15 Nb[3]Al. The ultimate temperature
at the ohmic-heating was controlled by the measurement of radiance
temperature on the surface of the tapes. The microstructures and the
superconducting properties of the tape p\specimens were investigated.
The highest Tc[on] is 18.5K, B[C2] up to 27T is obtained. Tc[on] of the
specimen prepared by the post annealing after the ohmic-heating
increases by 1.7K.
[TYPE]:Superconductors
[PROP]:Nb[3]Al, Nb[2]Al, powder metallurgy, microstructure
******************************************************************************
[ID ]:KL97-156
[AUTH]:Ikebe Manabu, Fujishiro Hiroyuki, Yagi Makoto and Fukase Tetsuo
[TITL]:Effect of Annealing on Thermal and Electrical Transport in
Nd[1.85]Ce[0.15]CuO[4]
[SOUR]:Superlattices Microstruct., 21[3] (1997), 357-362
[LAB ]:(1); Faculty of Eng., Iwate Univ.; Fukase
[ABST]:A quenching process followed by annealing in Ar atmosphere was
confirmed to stabilize superconductivity in sintered
Nd[1.85]Ce[0.15]CuO[4] crystals. The electrical resistivity and the
thermal conductivity were examined at each stage of the heat
treatments. The phonon scattering mechanisms are analyzed in a
systematic way.
[TYPE]:Superconductors
[PROP]:high-Tc cuprate, stabilization of superconductivity, phonon scattering,
electron scattering
******************************************************************************
[ID ]:KL97-157
[AUTH]:Ikeda Hiroshi, Tanaka Yoshiaki, Yoshizaki Ryozo, Ishizuka Masayuki and
Maeda Hiroshi
[TITL]:Alloy Sheath Effects of (Bi, Pb)[2]Sr[2]Ca[2]Cu[3]O[y] Tapes
[SOUR]:Proc. 16th Int. Cryogenic Engineering Conf. / Int. Cryogenic Materials
Conf., ed. by T. Haruyama, et al., Kitakyushu, 1996, (1997), 1385-1388
[LAB ]:(2); Inst. of Appl. Phys. and Cryogenics Center, Univ. of Tsukuba;
National Res. Inst. for Met., Tsukuba Magn. Lab.; Hiratsuka Res. Lab.,
Sumitomo Heavy Indust., Ltd.; Maeda
[ABST]:Ag-Cu alloy sheathed (Bi, Pb)[2]Sr[2]Ca[2]Cu[3]O[y] (Bi-2223) tapes
were prepared by the powder-in-tube method. We have introduced three
kinds of elements in the Ag90%-Cu10% alloy sheathed Bi-2223 tapes and
measured the change in critical current density (Jc). The three kinds
of elements were provided by Ti, Zr, and Hf. The result indicated the
difference in the observed temperature dependence of the magnetic Jc
among the samples. The transport Jc was 9 times 10]4[ A/cm]2[ at 4.2K
and H=14T for the Hf-doped sample. In addition, the field dependence of
magnetic Jc was improved for the Hf-doped sample. It seems that this
behavior is concerned with microstructures. Ag-Cu alloy sheath effect
of Bi-2223 tapes we discuss with the pinning force (Fp) and
microstructures.
[TYPE]:Superconductors
[PROP]:Bi 2223 tape, Ag-Cu alloy sheath, Jc property, magnetic hysteresis
curve, doping effect
******************************************************************************
[ID ]:KL97-158
[AUTH]:Ikeda Hiroshi, Tanaka Yoshiaki, Yoshizaki Ryozo, Ishizuka Masayuki,
Yoshikawa Kozo, Matsudaira Tsuneaki and Maeda Hiroshi
[TITL]:Magnetic Properties of Ag-Cu Alloy Sheathed (Bi,
Pb)[2]Sr[2]Ca[2]Cu[3]O[y] Tapes
[SOUR]:Proc. 9th Int. Symp. Superconductivity (ISS '96), ed. by S. Nakajima
and M. Murakami, Sapporo, (1997), 847-850
[LAB ]:(2); Univ. of Tsukuba; National Res. Inst. for Met.; Sumitomo Heavy
Industries; Mitsubishi Heavy Industries; Maeda
[ABST]:We measured the magnetic properties of Ag sheathed and Ag-Cu alloy
sheathed (Bi, Pb)[2]Sr[2]Ca[2]Cu[3]O[y](Bi-2223) tapes doped with Ti,
Zr and Hf. The samples were prepared by the powder-in-tube method. The
magnetic Jc was estimated from hysteresis loop of the M-H curves. The
magnetic field was applied perpendicular and parallel to the pressed
direction. The Jc value of the Hf doped Bi-2223 tapes was 2.5 times
10]5[ A/cm]2[ at 5K and 0T, and 5.3 times 10]4[ A/cm]2[ at 50K and 0T.
Those values are higher than for the Ag and doped Ag-Cu sheathed tapes.
In addition, the field dependence of magnetic Jc was improved for the
Hf-doped sample. Ag-Cu alloy sheath effect of Bi-2223 tapes is
discussed for the Hf doped sample with respect to the anisotropy
pinning force (Fp).
[TYPE]:Superconductors
[PROP]:(Bi, Pb)[2]Sr[2]Ca[2]Cu[3]O[y], Ag-Cu alloy, powder-in-tube, magnetic
J[c], pinning force
******************************************************************************
[ID ]:KL97-159
[AUTH]:Ishizuka Masayuki, Tanaka Yoshiaki, Hashimoto Takehiro and Maeda
Hiroshi
[TITL]:Influence of Doping Ti, Zr or Hf into Ag-Cu Alloy Sheath of Bi-2223
Tapes
[SOUR]:Proc. 16th Int. Cryogenic Engineering Conf. / Int. Cryogenic Materials
Conf., ed. by T. Haruyama, et al., Kitakyushu, 1996, (1997), 1377-1380
[LAB ]:(2); Res. and Develop. Center, Sumitomo Heavy Indus. Ltd.; Tsukuba
Magnet Lab., National Res. Inst. for Met.; Graduate Course, Univ. of
Tsukuba.; Maeda
[ABST]:Bi-2223 Ag-Cu alloy sheathed tapes doped with Ti, Zr or Hf were
prepared by powder-in-tube technique. Amounts of Cu in the Ag-Cu alloy
sheath and sintering condition were mainly investigated with respect to
superconducting property. The optimum heat treatment temperature and
time lie at about 827Ž and around 200 hours in total with two
intermediate pressings. The Ag-10at.%Cu alloy sheathed tape doped with
0.1at.%Hf indicated the J[c] values of 4.1 times 10]4[ A/cm]2[ at 4.2K,
14T and 1.7 times 10]4[ A/cm]2[ at 77K, 0T, respectively which were
larger than the J[c] of non-doped Ag-10at.% Cu alloy sheathed tapes.
The increase in J[c] for the doped tapes may be attributed primarily to
the improved texture due to plate-like large grains and enhancement of
phase alignment.
[TYPE]:Superconductors
[PROP]:Bi-2223 tape, AgCu alloy sheath, doping effect, J[c] property,
microstructure
******************************************************************************
[ID ]:KL97-160
[AUTH]:Iwaki Genzo, Kimura Morio, Sakai Shuji, Kobayashi Norio, Watanabe Kazuo
and Awaji Satoshi
[TITL]:Critical Current Density at High Fields for Bronze-Processed
(NbTiTa)[3]Sn Superconducting Wires
[SOUR]:Proc. 16th Int. Cryogenic Engineering Conf. / Int. Cryogenic Materials
Conf., ed. by T. Haruyama, et al., Kitakyushu, 1996, (1997), 1719-1722
[LAB ]:(1); Hitachi Cable, Ltd.; Kobayashi; HFLSM
[ABST]:To improve critical current density at high fields for bronze-processed
Nb[3]Sn superconducting wire, an optimization of process conditions for
a production-level bronze-processed (Nb cdot Ti cdot Ta)[3]Sn wire was
carried out. As the results, the highest non Cu Jc of 121 A/mm]2[ at 20
T, 4.2 K was obtained. The Bc2 for the wire was estimated 26.5T, the
n-value at 20T was 24. It has proved that bronze-processed (Nb cdot Ti
cdot Ta)[3]Sn superconducting wires has high potential for high fields
applications.
[TYPE]:Superconductors
[PROP]:Nb[3]Sn, (NbTiTa)[3]Sn, Superconducting Wire, critical current density,
high magnetic field
******************************************************************************
[ID ]:KL97-161
[AUTH]:Iwasaki Shoji, Goto Kenji, Sadakata Nobuyuki, Saito Takashi, Kohno
Osamu, Awaji Satoshi and Watanabe Kazuo
[TITL]:Mechanical and Superconducting Properties of Multifilamentary Nb[3]Sn
Wires with CuNb Reinforcing Stabilizer
[SOUR]:Proc. 16th Int. Cryogenic Engineering Conf. / Int. Cryogenic Materials
Conf., ed. by T. Haruyama, et al., Kitakyushu, 1996, (1997), 1723-1726
[LAB ]:(1); Mater. Res. Lab., Fujikura Ltd.; HFLSM
[ABST]:We developed bronze processed multifilamentary (Nb, Ti)[3]Sn wire with
CuNb reinforcing stabilizer, CuNb/(Nb,Ti)[3]Sn. So far, we proved that
CuNb/(Nb,Ti)[3]Sn wire had excellent mechanical properties as a test
coil using the developed wire endured actual electromagnetic force of
224MPa at 9 Tesla without any degradation of the coil. In this paper,
mechanical properties of the developed wire are tested and reported.
The results indicated its possibility to fabricate high-field magnets
of this wire by R&W technique.
[TYPE]:Superconductors
[PROP]:Nb[3]Sn, CuN reinforcement, mechanical properties, critical current
******************************************************************************
[ID ]:KL97-162
[AUTH]:Katagiri Kazumune, Watanabe Kazuo, Shin H.
[TITL]:Tensile Strain / Transverse Compressive Stress Effects in Nb[3]Sn
Multifilamentary Wires with CuNb Reinforcing Stabilizer
[SOUR]:Adv. Cryog. Eng. Mater., 42B (1997), 1423-1432
[LAB ]:(1); Faculty of Eng., Iwate Univ.; HFLSM; Dept. of Mech. Eng., Andong
National Univ.; Inst. Sci. Ind. Res., Osaka Univ.; Mater. Res. Lab.,
Fujikura Ltd.
[ABST]:In order to improve the strain/stress characteristics of the critical
current I[c], the use of external CuNb reinforcing stabilizer, instead
of the conventional Cu stabilizer, with bronze processed Nb[3]Sn
multifilamentary superconducting wires was examined up to the magnetic
field of 14T and at a temperature of 4.2K. Although the axial tensile
strain sensitivity of I[c] was not changed, the strain for peak I[c] as
well as the reversible strain limit increased by 0.14% when the Cu
stabilizer was replaced by the CuNb reinforcing stabilizer. On the
other hand, the transverse compressive stress sensitivity of I[c]
decreased and the reversible stress limit increased. An increase in
both a bronze to Nb ratio and Sn content in bronze matrix resulted in a
higher stress tolerance and, as a consequence, the contribution of the
CuNb reinforcement became relatively small.
[TYPE]:Superconductors
[PROP]:CuNb, Nb[3]Sn, mechanical properties, critical current, strain effect
******************************************************************************
[ID ]:KL97-163
[AUTH]:Kezuka Hiroshi, Kikuchi Masae, Ohshima Eriko, Hikosaka Hideaki and
Syono Yasuhiko
[TITL]:Characterization of Grain-Structure in Shocked YBCO Particles
[SOUR]:Physica C, 282-287 (1997), 521-522
[LAB ]:(1); Tokyo Eng. Univ.; Syono
[ABST]:Fine YBCO powders were shock-compacted at around 5GPa using a
propellant gun. Shock-compacted pellets have large grains of 5-25 mu m
in length with large growth-steps caused mainly b heats generated in a
shock-loading.
[TYPE]:Superconductors
[PROP]:YBa[2]Cu[3]O[y], shock compaction, grain-structure, fine particle,
superconductor
******************************************************************************
[ID ]:KL97-164
[AUTH]:Kikuchi Masae, Kanehashi Koji, Ohshima Eriko and Syono Yasuhiko
[TITL]:Superconductivity of (Pb, M)Sr[2](Y, Ca)Cu[2]O[y](M=Cu, Cd) in
Relevance to the Valence State of Lead
[SOUR]:Physica C, 282-287 (1997), 821-822
[LAB ]:(3); Syono
[ABST]:(Pb, M)Sr[2]Y[1-x]Ca[x]Cu[2]O[y](M=Cu, Cd) were synthesized over wide
range of x and oxygen content. Pb and Cu valences were analyzed by
chemical analysis. The oxygen contents of both M=Cu and Cd series
increased with decreasing Ca content. The maximum oxygen content of
M=Cd was near 7, while that of M=Cu series exceeded 7. The
superconductivity of both M=Cu and Cd at x=0.5 was discussed in
relevance to the valence state of Pb and site preference of Cu and Cd
ions in the Pb-O layer.
[TYPE]:Superconductors
[PROP]:(Pb, M)Sr[2](Y, Ca)Cu[2]O[y], superconductivity, valence analysis,
Pb-valence
******************************************************************************
[ID ]:KL97-165
[AUTH]:Matsuzaki Kunio, Shimizu Koichi, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Fabrication of Ag/Bi2223 Multilayer Tapes by the " Jelly Roll " Method
[SOUR]:Mater. Lett., 30[1] (1997), 99-103
[LAB ]:(1); Inoue; Furukawa Co. Ltd.; Masumoto
[ABST]:Multilayered (laminated) tapes consisting of Ag and the Bi2223 phase
were prepared by a jelly roll method. The highly oriented structure of
the Bi2223 phase is obtained over the whole region of the tape. The
J[c] of 8200A/cm]2[, corresponding to an I[c] of 14 A, is obtained for
rather thick tapes with a thickness of 0.25mm, which enables easy
handling. The thermomechanical treatment enhances J[c] and the miximum
value reaches 17200A/cm]2[, corresponding to an I[c] of 29.2A.
Therefore, the multilayered microstructure fabricated by the jelly roll
method is useful for the production of high J[c] and I[c] tapes with
the added feature of being easily handled without damage.
[TYPE]:Superconductors
[PROP]:superconducting, multilayer tape, jelly roll, Bi2223, Jc
******************************************************************************
[ID ]:KL97-166
[AUTH]:Matsuzaki Kunio, Shimizu Kouichi, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Highly Oriented Structure of Hot-Extruded Tl[2]Ba[2]Ca[2]Cu[3] Oxides
Prepared from MG Powders
[SOUR]:J. Mater. Sci. Lett., 16[4] (1997), 290-293
[LAB ]:(2); Inoue; Furukawa Co. Ltd.; Masumoto
[TYPE]:Superconductors
[PROP]:Tl[2]Ba[2]Ca[2]Cu[3]O[y], hot-extrusion, oxidesuperconductor, oriented
structure, MG
******************************************************************************
[ID ]:KL97-167
[AUTH]:Murase Satoru, Nakayama Shigeo, Koyanagi Kei, Masegi Tamaki, Nomura
Shunji, Urata Masami, Shimamura Keizo, Amano Kagetaka, Shiga Noriyuki,
Watanabe Kazuo and Kobayashi Norio
[TITL]:Development of the Alumina-Copper Reinforced Nb[3]Sn Wire for the Coil
Fabrication
[SOUR]:Proc. 16th Int. Cryogenic Engineering Conf. / Int. Cryogenic Materials
Conf., ed. by T. Haruyama, et al., Kitakyushu, 1996, (1997), 1707-1710
[LAB ]:(1); Toshiba Corp.; Showa Electric Wire & Cable Co., Ltd.; HFLSM;
Kobayashi
[ABST]:For fabrication of a large-bore and high-magnetic-field magnet which
achieves a low coil weight and volume, the alumina-Cu reinforced
Nb[3]Sn wire of 1 km in length has been developed using the tube
process by improving workability. The reinforced Nb[3]Sn wire showed
superior performances in superconducting and mechanical properties such
as high proof stress, high tensile stress tolerance up to 300Mpa class
and high transverse compressive stress tolerance. These values are over
twice as large as those of the ordinary Cu matrix wire. Using the
reinforced wire the model coil was fabricated to demonstrate high
mechanical strength.
[TYPE]:Superconductors
[PROP]:Al[2]O[3]-Cu, Nb[3]Sn, reinforcement, high field, stabilizer
******************************************************************************
[ID ]:KL97-168
[AUTH]:Nemoto Yoshihiro, Takeuchi Takao, Maeda Hiroshi and Togano Kazumasa
[TITL]:SN-Interface Flux Pinning in Bronze Processed V[3]Si Conductor
[SOUR]:Proc. 16th Int. Cryogenic Engineering Conf. / Int. Cryogenic Materials
Conf., ed. by T. Haruyama, et al., Kitakyushu, 1996, (1997), 1757-1760
[LAB ]:(2); Tsukuba Magn. Lab., National Res. Inst. for Met.; Maeda
[ABST]:A V[3]Si multifilamentary conductor produced by a modified bronze
process has 3 kinds of S-N Interfaces: V-V[3]Si, V[5]Si[3]-V[3]Si, and
Cu(Si)-V[3]Si. In order to investigate pinning characteristic of these
S-N interfaces, we measured the J[c](I[c])-B properties of a V[3]Si
tape with unsymmetrical interface configuration
(V/V[3]Si/V[5]Si[3]/Cu(Si)). J[c] was measured by rotating a sample in
a split magnet or by reversing current flow direction. It has been
found that the field dependence of V-V[3]Si pinning is different from
those of V[5]Si[3]-V[3]Si and Cu-V[3]Si interface pinnings. Field
dependence of V-V[3]Si interface pinning is rather similar to the field
dependence of grain boundary pinning.
[TYPE]:Superconductors
[PROP]:V[3]Si conductor, bronze processed, super-normal interface, magnetic
flux pinning
******************************************************************************
[ID ]:KL97-169
[AUTH]:Ohkura Kengo, Ueyama Munetugu, Sato Ken-ichi, Awaji Satoshi and
Watanabe Kazuo
[TITL]:Electromagnetic Strain of a BSCCO-2223 Silver-Sheathed Tape Reinforced
by a Stainless Steel Tape
[SOUR]:Proc. 16th Int. Cryogenic Engineering Conf. / Int. Cryogenic Materials
Conf., ed. by T. Haruyama, et al., Kitakyushu, 1996, (1997), 1365-1368
[LAB ]:(1); Sumitomo Electric Industries, Ltd.; HFLSM
[ABST]:We examined a stainless steel reinforcement for Bi-2223 silver-sheathed
tapes. Two types of bundled tapes were wound on a bobbin made of
copper. One was reinforced by a stainless steel and the other was not
reinforced. 4-pieces of strain-gages were settled on each
silver-sheathed tape. The background magnetic field was applied from 3T
to 15T and coil current was varied up to 180A. It was found elastic
modulus for a stainless steel reinforced tape was about 125Gpa and that
for the tape without a stainless steel tape was about 102Gpa. A
stainless steel reinforcement for a Bi-2223 tape can work well.
[TYPE]:Superconductors
[PROP]:Bi-2223 silver-sheathed tape, stainless steel tape, reinforcement
superconducting coil, strain gauge
******************************************************************************
[ID ]:KL97-170
[AUTH]:Ohshima Eriko, Atou Toshiyuki, Kikuchi Masae and Syono Yasuhiko
[TITL]:Stabilization of Tl-Sr 1223 Phase by High-Pressure Synthesis and Mo-
and Re-Substitution for Tl
[SOUR]:Physica C, 282-287 (1997), 827-828
[LAB ]:(3); Syono
[ABST]:Single phase of TlSr[2]Ca[2]Cu[3]O[y] was synthesized at 1000Ž and
2.5GPa for 4 h. The T[c] was measured at 97K by SQUID. Stabilization of
TlSr[2]Ca[2]Cu[3]O[y] structure by Mo and Re substitution to the Tl
site were also carried out at ambient pressure.
[TYPE]:Superconductors
[PROP]:TlSr[2]Ca[2]Cu[3]O[y], high-pressure, Mo-, Re-substitution,
superconductor, synthesis
******************************************************************************
[ID ]:KL97-171
[AUTH]:Okada Michiya, Tanaka Kazuhide, Sato Junichi, Awaji Satoshi and
Watanabe Kazuo
[TITL]:Critical Current Density of Bi[2]Sr[2]Ca[1]Cu[2]O[x]/Ag
Multifilamentary Tape
[SOUR]:Proc. 7th US-Japan Workshop High-T[c] Superconductor, Tsukuba, ed. by
K. Tachikawa, et al., (1997), 305-310
[LAB ]:(1); Hitachi Res. Lab.; Hitachi Cable Ltd.; HFLSM
[ABST]:Ag-sheathed Bi[2]Sr[2]Ca[1]Cu[2]O[x] tapes with 19 and 55 cores were
fabricated by a powder-in-tube process. The multiflamentary tapes
showed critical current densities J[c] of 1800A/mm]2[ (B parallel tape
surface), 1070A/mm]2[ (B perp tape surface) at 4.2K and 23T, and
1710A/mm]2[ (B parallel tape surface) at 4.2K and 30T, showing a
practical range of current carrying capacities. The maximum J[c], 4900
A/mm]2[ (critical current I[c] = 550A) was observed for a 55-filament
tape at 4.2K and 0T. The mechanical properties were also investigated
in relation to the multifilamentary structure.
[TYPE]:Superconductors
[PROP]:Bi[2]Sr[2]Ca[1]Cu[2]O[x], multifilamentary tape, critical current
density
******************************************************************************
[ID ]:KL97-172
[AUTH]:Sasaki Takako, Yamada Kenji, Watanabe Kazuo, Watauchi Satoshi, Kishio
Kohji and Kobayashi Norio
[TITL]:Nernst Effect in the Mixed State of YBa[2]Cu[3]O[7-delta] and
Bi[2.1]Sr[1.8]Ca[1]Cu[2]O[8+delta]
[SOUR]:Physica C, 282-287 (1997), 2009-2010
[LAB ]:(2); Kobayashi; HFLSM; Univ. of Tokyo
[ABST]:The Nernst effect has been measured for the anisotropic and extremely
anisotropic superconductors YBa[2]Cu[3]O[7-delta] and
Bi[2.1]Sr[1.8]Ca[1]Cu[2]O[8+delta] in the magnetic field up to 14T
parallel to the c-axis. From the Nernst electric field the transport
entropy per unit length of a flux line is estimated. The relationship
between the transport entropy and the anisotropy of high-T[c]
superconductor is discussed.
[TYPE]:Superconductors
[PROP]:YBa[2]Cu[3]O[7-delta], Bi[2.1]Sr[1.8]Ca[1]Cu[2]O[8+delta], Nernst
effect, transport entropy, anisotropy
******************************************************************************
[ID ]:KL97-173
[AUTH]:Sekiyama Akira, Susaki Takashi, Fujimori Atsushi, Sasaki Takahiko,
Toyota Naoki, Kondo Tetsuo, Saito Gunji, Tsunekawa M., Iwasaki T., Muro
T., Matsushita T., Suga S., Ishii H. and Miyahara T.
[TITL]:High-Resolution Photoemission Study of Metallic, Insulating, and
Superconducting BEDT-TTF Salts
[SOUR]:Phys. Rev. B, 56[14] (1997), 9082-9090
[LAB ]:(2); Dept. of Phys., Tokyo Univ.; Fukase; Res. Inst. for Adv. Sci. and
Technol., Osaka Prefecture Univ.; Dept. of Chem., Kyoto Univ.; Dept. of
Mater. Phys., Osaka Univ.; Dept. of Phys., Tokyo Metropolitan Univ.
[ABST]:We have made a high-resolution photoemission study of
quasi-two-dimensional organic conductors BEDT-TTF salts which have
various ground states, namely, antiferromagnetic insulator
kappa-(ET-d[8])[2] Cu[N(CN)[2]]Cl, paramagnetic metal
alpha-(ET)[2]KHg(SCN)[4], and superconductors kappa-(ET)[2]Cu(NCS)[2]
and kappa-(ET)[2]Cu[N(CN)[2]]Br, where ET denotes BEDT-TTF or
bisethylenedithio-tetrathiafulvalene. In all the spectra, the
photoemission intensity is suppressed near the Fermi level (E[F]),
especially for the kappa-phase salts, although we have clearly observed
a finite E[F] intensity for alpha-(ET)[2]KHg(SCN)[4]. Hartree-Fock
band-structure calculations for the paramagnetic metallic and
antiferromagnetic insulating states qualitatively explain the spectra
of alpha-(ET)[2]KHg(SCN)[4] and kappa-(ET-d[8])[2]Cu[N(CN)[2]]Cl,
respectively, while those of kappa-(ET)[2]Cu(NCS)[2] and
kappa-(ET)[2]Cu[N(CN)[2]]Br strongly deviate from the calculations for
the corresponding ground states. These observations imply that, among
the metallic compounds, electrons are more strongly correlated in the
kappa-phase salts than in alpha-(ET)[2] KHg(SCN)[4]. It is shown that
long-range electron correlation is quite important to explain the
strong deviation of the spectra from the band-structure calculation.
The spectra of the kappa-phase salts exhibit a remarkable similarity
between the metallic (superconducting) and insulating phases across the
chemical pressure-induced phase transition. We have also observed
unusual temperature dependence of the spectra for
kappa-(ET)[2]Cu(NCS)[2], alpha-(ET)[2]KHg(SCN)[4], and
kappa-(ST-d[8])[2]Cu[N(CN)[2]]Cl.
[TYPE]:Superconductors
[PROP]:organic conductor, organic superconductor, photoemission
******************************************************************************
[ID ]:KL97-174
[AUTH]:Suzuki Takao, Goto Takayuki, Chiba Kaichiro, Shinoda Tomoyuki, Fukase
Tetsuo, Kimura Hiroyuki, Yamada Kazuyoshi, Ohashi Masayoshi and
Yamaguchi Yasuo
[TITL]:Observation of Modulated Magnetic Long-Range Order in
La[1.88]Sr[0.12]CuO[4]
[SOUR]:Phys. Rev. B, 57[6] (1997), R3229-R3232
[LAB ]:(2); Fukase; Dept. of Phys., Tohoku Univ.; Yamayasu
[ABST]:Magnetic superlattice peaks are observed in single-crystal
neutron-diffraction measurements on orthorhombic La[1.88]Sr[0.12]CuO[4]
at reciprocal points of (1/2 pm epsilon, 1/2,0) and (1/2, 1/2 pm
epsilon, 0) in the tetragonal notation where epsilon=0.126 pm 0.003.
The La NMR measurement reveals a broadening of the field-swept spectrum
below sim45K corresponding to the existence of magnetic order. The
remarkable softening of longitudinal sound waves along [110] is
observed in the same crystal. The features observed in the neutron
diffraction, NMR, and ultrasonic measurements suggest that the
dynamical incommensurate spin correlation is pinned by a lattice
instability toward the low-temperature tetragonal phase.
[TYPE]:Superconductors
[PROP]:La[2-x]Sr[x]CuO[4], neutron-diffraction, magnetic superlattice
******************************************************************************
[ID ]:KL97-175
[AUTH]:Takahama Masahide, Goto Tomoko, Watanabe Kazuo and Awaji Satoshi
[TITL]:Transport Current Density up to 10T at 77K in Filamentary
YBa[2]Cu[3]O[7] Superconductor
[SOUR]:Physica C, 282-287 (1997), 2287-2288
[LAB ]:(1); Nagoya Inst. of Technol.; HFLSM
[ABST]:Filamentary Y123 superconductores were prepared by solution spinning
and partial-melt-process. The fiber axis of the filament is normal to
the c-axis of the orthorhombic phase. A transport J[c] for the sample
was examined in magnetic fields up to 10T at 77K. A current was passed
to the direction of the fiber axis was always normal to the applied
magnetic field. For the direction to the fiber diameter, the J[c] value
of the sample with random orientation was higher than that for the
sample with c-axis orientation texture. The sample with random
orientation has a J[c] of 10]4[ A/cm]2[ at 77K and 0T. Although the
J[c] value 10]3[ A/cm]2[ at 4T of the sample slightly decreased with
the applied field, the J[c] value of more than 10]2[ A/cm]2[ was
maintained at 10T.
[TYPE]:Superconductors
[PROP]:YBa[2]Cu[3]O[7], high temperature superconducting filament, critical
current
******************************************************************************
[ID ]:KL97-176
[AUTH]:Takeuchi Takao, Nemoto Yoshihiro, Itoh Kikuo, Iijima Yasuo, Kosuge
Michio, Inoue Kiyoshi and Maeda Hiroshi
[TITL]:Superconducting Properties of V[3]Si Multifilamentary Conductor
[SOUR]:Adv. Cryog. Eng. Mater., 42B (1997), 1391-1398
[LAB ]:(2); National Res. Inst. for Met.; Maeda
[ABST]:A flattened V[3]Si multifilamentary conductor was prepared by
cold-rolling a wire-composite, and then changes in morphology and
configuration of the superconductor-normal metal (S-N) interface and
grain boundaries were induced. Correlation between microstructure and
the angular dependence of J[c] with respect to the transverse field
direction indicates clearly the existence of two kinds of pinning
centers. The S-N interface acts as a dominant pinning center for
parallel fields and becomes important in low magnetic fields, in
particular for composites with fine V filaments. The element pinning
force of the S-N interface was estimated from F[p] vs (V[3]Si layer
thickness)]-1[ relationship.
[TYPE]:Superconductors
[PROP]:V[3]Si, superconducting multifilamentary wire, flux pinning
******************************************************************************
[ID ]:KL97-177
[AUTH]:Tanaka Yoshiaki, Ishizuka Masayuki, He Lian Long, Horiuchi Shigeo and
Maeda Hiroshi
[TITL]:Microstructures and Superconducting Properties of Ag Alloy Sheathed
Bi-2223 Tapes
[SOUR]:Adv. Cryog. Eng. Mater., 42B (1997), 559-566
[LAB ]:(2); National Res. Inst. for Met.; National Inst. for Res. in Inorganic
Mater.; Inst. of Met. Res., Acad. China; Sumitomo Heavy Industries;
Maeda
[ABST]:Bi-2223 superconducting tapes were prepared by the powder-in tube
technique using Ag-10at% Cu-x at%M (M=Ti, Zr or Hf, X=0-1.0) alloy
sheaths. The alloy sheathed tapes with a very small amount doping of
Ti, Zr or Hf, the doped tapes, exhibited considerably higher J[c]
values than those of pure Ag or Ag-10at%Cu sheathed tapes, the
non-doped tapes. The highest J[c] values at 4.2K/14T and 77K/0.4T
reached around 9.0x and 1.0 times 10]4[ A/cm]2[, respectively, for the
doped tapes, especially for the 0.1-0.03at%Ti or 0.1at%Hf doping.
Compared with the non-doped tapes, the doped tapes show in most case
larger magnetic moment. SEM microstructures observed on the core
surfaces of these tapes revealed large flat-shaped Bi-2223 grains
containing neither subgrains nor small stick-shaped grains.
Furthermore, high resolution transmission electron microscope revealed
that amorphous disc-like regions with less than 5 nm in thickness
parallel to (001) plane were introduced into Bi-2223 lattice in
parallel to CuO[2] layer. These changes in grain morphology and
existence of amorphous disc-like regions may strongly be related to the
high J[c] properties of the doped tapes, especially the amorphous
regions may play the important role as one of pinning centers.
[TYPE]:Superconductors
[PROP]:Bi-2223, high-Tc superconductor, superconducting tape, Ag-Cu alloy
******************************************************************************
[ID ]:KL97-178
[AUTH]:Iwasaki Naoya, Hojo Masaki, Ochiai Shojiro, Ono Masayoshi, Sakai Shuji
and Watanabe Kazuo
[TITL]:Structure Observed by Neutron Diffraction, Mechanical Behavior and
Critical Current of Multifilamentary Nb-Ti/Cu Superconducting Composite
Wire (in Japanese)
[SOUR]:Nippon Kinzoku Gakkaishi (J. Jpn. Inst. Met.), 61[9] (1997), 792-800
[LAB ]:(1); Mesoscopic Mater. Res. Center, Faculty of Eng., Kyoto Univ.; Res.
Reactor Inst., Kyoto Univ.; Hitachi Cable, Ltd.; HFLSM
[ABST]:Neutron diffraction measurements were carried out on multifilamentary
Nb-Ti/Cu superconducting composite wire in order to clarify the
structural anisotropy and the residual stresses arising from the
fabrication process. Highly oriented structure was observed both for
copper and Nb-Ti components. The residual stress of copper in the
composite wire was estimated to by 40MPa by means of PSD method, which
was close to the yield stress of matrix, 30MPa. The reason why the
measured elastic modulus is lower than the predicted one based on the
simple rule of mixtures was accounted for from the viewpoint of the
formation of the texture. While the failure strain of filaments tested
separately was nearly 2%, that of the composite with the copper ratio
7.83 was about 20%. The high failure strain of the composite was
achieved through the formation of multiple necking of the embedded
filaments. The average strength of the extracted filaments was 1240MPa,
which was about 10 times higher than that of the oxides and comparable
to that of A15 compounds. The scatter of strength was much smaller than
that of the oxides and A15 compounds. The critical current decreased
with increasing applied strain, but nearly 80% of the critical current
for unloaded samples was retained even after deformation up to 20%
strain due to the enhanced failure strain of the filaments through the
multiple necking.
[TYPE]:Superconductors
[PROP]:niobium-titanium, superconducting composite wire, neutron diffraction,
texture, residual stress, multiple necking, critical current
******************************************************************************
[ID ]:KL97-179
[AUTH]:Kusunoki Masanobu, Osuka Akira, Ehata Katsufumi, Ohshima Sigetoshi,
Masumoto Hiroshi and Hirai Toshio
[TITL]:Preparation of YBa[2]Cu[3]O[y] Thin Films Using Induction-Coil-Coupled
Sputtering (in Japanese)
[SOUR]:Nippon Kinzoku Gakkaishi (J. Jpn. Inst. Met.), 61[9] (1997), 951-955
[LAB ]:(1); Dept. of Elect. and Infor. Eng., Faculty of Eng., Yamagata Univ.;
Hirai
[ABST]:YBa[2]Cu[3]O[y] (YBCO) superconducting thin films were deposited on MgO
single crystals by induction-coil-coupled sputtering. The effects of
the induction coil on the qualities of YBCO thin films are examined.
Uniformity of film thicknesses below pm5% was obtained over an area of
40mm diameter using a 50mm diameter target by the condition of the
substrate-target distance of 90mm. Even in the area of 60mm diameter
which was wider than that of the target, the uniformity of thickness
within pm17% was obtained. In order to clarify the effects of the
induction-coil, we studied the dependence of the critical temperature
(T[c]) and the full width at half maximum (FWHM) of the films on the
applying power of coil. T[c] and FWHM showed optimum values at the
applying coil power of 70W. It is confirmed from these results that the
induction-coil operated effectively to fabricate high quality films.
The epitaxial relations of YBCO films on MgO single crystal substrates
were examined by X-ray pole figure measurements. Basically film of YBCO
was aligned with the c-axis perpendicular to the substrate surface. The
film deposited at the coil power of 70W exhibited well single-oriented
grains with the a- or b-axis parallel to the a -axis of MgO. However,
films deposited at the applying coil power of 0W contained grains with
two different orientations which were rotated by 45K. Scanning
electron microscopy (SEM) of the film surface showed the films to
consist of a smooth background surface and a distribution of particles.
Energy dispersive X-ray analysis (EDAX) measurements showed that the Ba
concentration was larger than that of exact stoichiometric composition.
Auger electron spectroscopy (AES) revealed that the elements contained
in the particles were richer in Ba than in the smooth background
surface. The BaCuO[2] particles seemed to precipitate on the surface of
the film.
[TYPE]:Superconductors
[PROP]:YBa[2]Cu[3]O[y], superconducting thin film, induction-coil-coupled
sputtering
******************************************************************************
[ID ]:KL97-180
[AUTH]:Matsui Hideki, Fukumoto Kenichi, Kimura Akihiko, Kaneda Kazunori and
Kondo Takeyuki
[TITL]:Progress in Radiation Effect Studies of Low Activation Vanadium Alloys
for Fusion
[SOUR]:Fusion Energy 1996: Proc. 16th Int. Conf. Fusion Energy, Int. At.
Energy Agency, 3 (1997), 507-515
[LAB ]:(3); Matsui
[ABST]:Vanadium alloys have a number of attractive features for fusion reactor
structural applications. Their inherent low induced radioactivity, high
operating temperature, high thermal stress factor and superior
resistance against radiation damage are essential for the
attractiveness of fusion systems. The emphasis of recent vanadium
studies has been on alloy compositions centred about V-4Cr-4Ti. These
alloys have a very low ductile to brittle transition temperature (DBTT)
and good high temperature mechanical properties. Among a number of
radiation induced effects, swelling, DBTT shift and helium embitterment
may be the most important phenomena for fusion structural materials.
Data for V-4Cr-4Ti on swelling caused by neutron irradiation are
available only up to about 30dpa; swelling is less than 0.5% at this
dpa level in the swelling peak temperature region around 600Ž. The
DBTT shift caused by neutron irradiation above about 400Ž is very
small for V-4Cr-4Ti alloy. A larger DBTT shift has been reported after
irradiation at temperatures below about 300Ž. Low dose irradiation in
this low temperature range resulted in a greater radiation induced
hardening for a higher irradiation@temperature. This result is in
accordance with the larger DBTT shift after irradiation at a higher
temperature. Although the design temperature of vanadium alloys is well
above these temperatures, this low temperature radiation embitterment
needs closer examination. Helium embitterment has been studied using a
variety of helium doping techniques in the past. The degree of
embitterment depends strongly on the method of helium doping. Helium
preinjection by the tritium trick yielded rather severe ductility loss
in all the vanadium binary alloys tested at 800Ž. There was some doubt
about this strong embitterment, which was suspected to be due to the
peculiar helium configuration inherent to the tritium trick technique.
A new technique called the dynamic helium charging experiment has been
adopted to study helium effects on the high temperature ductility. With
this technique helium is generated concurrently with neutron
irradiation. Vanadium binary alloys have been demonstrated to retain
almost the same level of ductility as those specimens with simple
neutron irradiation. Thus helium embitterment is probably not so
significant as once suspected. The paper reviews the status of vanadium
alloy studies, especially of radiation effects, and also presents
recent results concerning helium effects on the swelling and mechanical
properties.
[TYPE]:Nuclear Materials
[PROP]:fusion reactor, vanadium alloys, radiation effects, mechanical
properties, helium effect
******************************************************************************
[ID ]:KL97-181
[AUTH]:Satoh Isamu, Takahashi Mitsuyuki and Miura Shigeyuki
[TITL]:Preparation of UO[2] Fine Particle by Hydrolysis of Uranium(IV)
Alkoxide
[SOUR]:Sci. Rep. RITU, A45[1] (1997), 11-13
[LAB ]:(2); Alpha; Gijutsu
[ABST]:Fine particles of uranium (IV) dioxides were obtained by hydrolysis of
uranium (IV) ethoxide which was synthesized by reacting uranium
tetrachloride with sodium ethoxide. The monodispersed submicrometer
particles were confirmed by SEM observation.
[TYPE]:Nuclear Materials
[PROP]:uranium(IV) alkoxide, uranium(IV) ethoxide, uranium tetrachloride,
UO[2] fine particle
******************************************************************************
[ID ]:KL97-182
[AUTH]:Shiokawa Yoshinobu, Hasegawa Kazuki, Konashi Kenji, Takahashi Mitsuyuki
and Suzuki Kenji
[TITL]:Preparation of High Purity Uranium Metal from Aqueous Solutions
[SOUR]:J. Alloys Compd., 255 (1997), 98-101
[LAB ]:(2); Shiokawa; Oarai; Gijutsu; Suzuki
[ABST]:The uranium amalgam was quantitatively prepared by electrolysis from
the aqueous solution containing acetic acid and sodium acetate using a
mercury cathode. A bright button or brown porous one of uranium metal
was obtained by thermal decomposition of the amalgam. The purity was
found to be much higher than commercial grade metal of ca. 99.95%. As a
result of this work, the simple and easy procedure for preparation of
uranium metal with a high level of purity on the laboratory scale has
been developed.
[TYPE]:Nuclear Materials
[PROP]:uranium metal, high purity metal, amalgam, electrolysis
******************************************************************************
[ID ]:KL97-183
[AUTH]:Shiokawa Yoshinobu, Hasegawa Kazuki, Takahashi Mitsuyuki and Suzuki
Kenji
[TITL]:Development of the Method for Preparation of Actinide Metals
[SOUR]:Sci. Rep. RITU, A45[1] (1997), 67-70
[LAB ]:(2); Shiokawa; Gijutsu; Suzuki
[ABST]:The uranium amalgam was quantitatively prepared by electrolysis from
the aqueous solution containing acetic acid and sodium acetate using
mercury cathode. A bright button or brown porous one of uranium metal
was obtained by thermal decomposition of the amalgam. The purity was
found to be much higher than commercial grade metal of ca.99.95%. As a
result of this work, the simple and easy procedure for preparation of
uranium metal with high purity level on the laboratory scale has been
developed.
[TYPE]:Nuclear Materials
[PROP]:uranium metal, actinide metals, high purity metal, amalgam,
electrolysis
******************************************************************************
[ID ]:KL97-184
[AUTH]:Tsunekawa Shin, Barnakov Yu A, Poborchii V.V, Samoilovich S.
[TITL]:Characterization of Precious Opals: AFM and SEM Observations, Photonic
Band Gap, and Incorporation of CdS Nano-Particles
[SOUR]:Microporous Mater., 8[5,6] (1997), 275-282
[LAB ]:(2); Fukuda; Ioffe Phys. Tech. Inst.; Moscow State Univ., Russia; DRAM;
Nishina
[ABST]:Gem-quality blue opals consisting of approx 200nm silica spheres are
synthesized and incorporated with CdS nano-paricles by a solution
technique. The opals with and without CdS are characterized by atomic
force microscopy, scanning electron microscopy and conventional optical
spectroscopic measurements. The possibility of producing 3-dimensional
arrays of nano-sized materials and photonic crystals is supported by
these experiments.
[TYPE]:Nuclear Materials
[PROP]:synthetic opal, cadomium sulfide, atomic force microscopy, scanning
electron microscopy, photonic band gap
******************************************************************************
[ID ]:KL97-185
[AUTH]:Yamazaki Kouzou, Sagara Akio, Motojima Osamu, Fujiwara Masami, Amano
Tsuneo, Chikaraishi Hirotaka, Imagawa Shinsaku, Muroga T., Noda
Nobuaki, Ohyabu Nobuyoshi, Satow Takashi, Wang Ji Feng, Watanabe
Kiyomasa Y., Yamamoto Junya, Yamanishi Hirokuni, Kohyama Akira, Matsui
Hideki, Mitarai Osamu, Noda Tetsuji, Shishkin A.A
[TITL]:Design Assessment of HELIOTRON Reactor
[SOUR]:Fusion Energy 1996: Proc. 16th Int. Conf. Fusion Energy, Int. At.
Energy Agency, 3 (1997), 421-433
[LAB ]:(2); NIFS; Matsui; Kyoto Univ.; Kyushu Tokai Univ.; NRIM; NSC Kharkov
Physics and Tech. Inst., Ukraine; Univ. of Tokyo
[ABST]:Helical reactor designs are studied on the basis of the physics and
engineering concept of the Large Helical Device (LHD), which is
characterized by two advantages: an efficient, closed helical divertor
and a simplified continuous coil system. First, optimization studies of
elle=2 conventional LHD type reactors (LHD-R) have been carried out.
One point plasma modeling, in addition to 3-D equilibrium/1-D transport
analysis, has clarified the D-T ignition condition. An accessible
design window for reactor parameters is found by using physics and
engineering constraints. A cost estimate suggests the importance of the
compact design in reducing the cost of electricity. Second, a new
reactor design candidate, the modular heliotron reactor (MHR), is
proposed; it is focused on the advantage of at efficient helical
divertor that is compartible with the modular helical coil system. A
special coil winding system permits an appropriate coil gap for reactor
module maintenance, and makes good plasma confinement and an efficient
helical divertor configuration compatible with each other. Two MHR
design options are selected on the basis of the LHD-R system analysis.
Third, by marking use of the advantage of the simplified continuous
coil design, a high field force helical rector (FFHR) is proposed in
order to reduce the electromagnetic force by adopting an ell=3 force
free like continuous coil system. The molten salt FLiBe, LiF-BeF[2], is
selected in FFER as a self-cooling tritium breeder, from the viewpoint
of safety and compatibility with the high magnetic field design.
[TYPE]:Nuclear Materials
[PROP]:fusion reactor, vanadium alloys, ferritic steels, radiation effects,
mechanical properties
******************************************************************************
[ID ]:KL97-186
[AUTH]:El-Eskandarany M.
[TITL]:Plasma Activated Sintering for Consolidation of Mechanically Reacted
TiN Powder
[SOUR]:Funtai oyobi Funmatsu Yakin (J. Jpn. Soc. Powder Powder Metall.), 44[6]
(1997), 547-553
[LAB ]:(1); Suzuki; Hirai
[ABST]:Nanocrystalline titanium nitride (Ti[56]N[44]) power with an average
grain size of 5 nm has been synthesized by ball-milling elemental Ti
powder under flow of nitrogen gas at room temperature. During the first
stage of the reactive ball milling time (0ks-3.6ks), the metallic Ti
particles agglomerate to form powder particles with larger diameter. At
the second stage (3.6ks-22ks), these agglomerated particles are
disintegrated to form smaller particles. The disintegrated particles
which have fresh surfaces begin to react with nitrogen (milling
atmosphere) during the third stage of milling (22ks-86ks) to form TiN
powder coexisting with unreacted metallic Ti powder. Towards the end of
milling (86ks-173ks), a single phase of nanocrystalline TiN with
NaCl-structure was obtained. The powder of this end product has
spherical like morphology with an average particle size of about 0.4mu
m in diameter. A consolidation procedure using a plasma activated
sintering method has been employed to consolidate the powder particles
at the several stages of the reactive ball milling. The density
measurements of the consolidated samples show that after 86ks to 173ks
of the reactive ball milling time, the compacted samples are fully
dense. The results have shown also that the consolidated TiN compacts
still maintain their unique nanocrystalline properties with an average
grain size of about 65nm. The hardness and some mechanical properties
of the consolidated TiN compacts have been determined as a function of
the reactive ball milling time.
[TYPE]:Composite Materials
[PROP]:titanium nitride, reactive ball milling, nanocrystalline, plasma
activated sintering
******************************************************************************
[ID ]:KL97-187
[AUTH]:Kojima Yuumi, Isobe Tetsuhiko, Senna Mamoru, Sakurai Masaki, Sumiyama
Kenji and Suzuki Kenji
[TITL]:An XAFS Study on Reconstruction of Short-Range Order in Mechanically
Alloyed Al-Ti and Al-Ti-O Complexes
[SOUR]:J. Alloys Compd., 248 (1997), 52-58
[LAB ]:(1); Faculty of Sci. and Technol., Keio Univ.; Suzuki
[ABST]:Mechanically alloyed (MA) Al-Ti and Al-O-Ti complexes have been studied
by X-ray absorption fine structure (XAFS) at the Ti K-edge. In the MA
mixture of Al and Ti, the single pre-edge peak due to the electron
transition 1s rightarrow 3d disappears, and the intensity of the first
nearest neighbor peak in the EXAFS structure function mid F(r) mid
decreases. In the MA mixture of Al and TiO[2] hydrogel, the number of
pre-edge peaks apparently decreases from three to one. At the same
time, the intensity of the mid F(r) mid peak due to the first nearest
neighbor increases, and its position approaches that of Al[2]TiO[5].
Similar phenomena are observed in the MA mixture of Al[2]O[3] and
TiO[2] hydrogels. These results suggest that mechanical stressing
causes characteristic electronic interaction and the reconstruction of
short-range order though intimate mixing at an atomic level. This
accords with our previous NMR studies.
[TYPE]:Composite Materials
[PROP]:aluminium-titanium, aluminium-titanium oxide, mechanical alloying,
mechanochemical complex, x-ray absorption fine structure
******************************************************************************
[ID ]:KL97-188
[AUTH]:Li Jianhui, Goto Takashi and Hirai Toshio
[TITL]:Thermoelectric Properties of B[4]C-TiB[2] Composites Prepared by Arc
Melting
[SOUR]:Proc. 14th Int. Japan-Korea Semin. Ceramics, Kanazawa, (1997), 64-68
[LAB ]:(3); Hirai
[ABST]:B[4]C-TiB[2] quasi-binary composites were prepared by arc melting in an
argon atmosphere. Fine lamella texture indicating eutectic reaction was
observed. The eutectic composition was determined to be about 25mol%
TiB[2]. The electric conductivity (sigma) of the B[4]C-TiB[2]
composites significantly increased with increasing TiB[2] content,
changing from semiconductor-like to metallic conduction. The thermal
conductivity (kappa) of all the composites was almost independent of
temperature. The kappa values increased with increasing TiB[2] content
at more than 6mol%, but were slightly smaller than that of B[4]C at
2mol%TiB[2]. The Seebeck coefficient (alpha) (p-type) and the
dimensionless figure-of merit (ZT, Z=alpha]2[ sigma/kappa) increased
with increasing temperature. Both the alpha and ZT values showed maxima
at 6mol%TiB[2]. The greatest ZT value obtained in the present work was
0.55 at 1100K for the B[4]C-6mol%TiB[2] composite.
[TYPE]:Composite Materials
[PROP]:arc-melt, boron carbide, titanium boride, high-temperature,
thermoelectric properties
******************************************************************************
[ID ]:KL97-189
[AUTH]:Mabuchi Mamoru, Iwasaki Hajime, Jeong Ha Guk, Hiraga Kenji and Higashi
Kenji
[TITL]:Critical Assessments of Accommodation Process by Liquid Phase for
Superplastic Flow in Si[3]N[4]/Al-Mg-Si Metal Matrix Composites
[SOUR]:J. Mater. Res., 12[9] (1997), 2332-2336
[LAB ]:(2); National Industrial Res. Inst. of Nagoya; Himeji Inst. of
Technol.; Hiraga; Osaka Prefecture Univ.
[ABST]:A liquid phase serves to relax stress concentrations caused by sliding
at interfaces and grain boundaries in high-strain-rate superplasticity
for aluminum matrix composites. However, the presence of a liquid phase
does not always lead to high-strain-rate superplasticity because too
mach liquid causes decohesion at a liquid phase. The critical
conditions of the optimum distribution, thickness, and volume in a
liquid phase are discussed based on the observation results by
differential scanning calorimetry and transmission electron microscopy.
As a result, a very thin and discontinuous liquid phase is required
both to assist relaxation of the stress concentrations and to limit
decohesion at a liquid phase.
[TYPE]:Composite Materials
[PROP]:Si[3]N[4]/Al-Mg-Si, liquid phase, metal composite, superplasticity
******************************************************************************
[ID ]:KL97-190
[AUTH]:Mabuchi Mamoru, Jeong Ha Guk, Hiraga Kenji and Higashi Kenji
[TITL]:Partial Melting at Interfaces and Grain Boundaries for High-Strain-Rate
Superplastic Materials
[SOUR]:Interface Sci., 4[3/4] (1997), 357-368
[LAB ]:(2); National Industrial Res. Inst. of Nagoya; Hiraga; Osaka Prefecture
Univ.
[ABST]:The present paper describes partial melting at matrix/reinforcement
interfaces and grain boundaries for high-strain-rate superplastic
metallic materials. It is suggested from the mechanical testing results
that partial melting is associated with the deformation mechanisms of
the high-strain-rate superplasticity. DSC measurements and TEM
observations reveal that solute additions are segregated at the
interfaces and grain boundaries, so that partial melting occurs at
elevated temperatures. This supports the concept of the accommodation
helper mechanisms such as the accommodation by a liquid phase. However,
when a liquid phase is continuous and thick, intergranular decohesion
is caused at liquid interfaces and grain boundaries. Therefore a
discontinuous and thin liquid phase is required both to play a vital
roll as an accommodation helper and to limit intergranular decohesion.
[TYPE]:Composite Materials
[PROP]:superplasticity, partial melting, segregation, interface
******************************************************************************
[ID ]:KL97-191
[AUTH]:Zhang Lian Meng, Li Jing Feng, Watanabe Ryuzou and Hirai Toshio
[TITL]:High-Temperature Ductility of TiC as Evaluated by Small Punch Testing
and the Effect of Cr[3]C[2] Additive
[SOUR]:Functionally Graded Materials 1996: Proc. 4th Int. Symp. Functionally
Graded Materials, ed. by I. Shiota and Y. Miyamoto, (1997), 445-450
[LAB ]:(2); Hirai; Dept. of Mater. Processing, Faculty of Eng., Tohoku Univ.
[ABST]:To study the mechanism by which TiC/Ni[3]Al FGMs are damaged under
cyclic thermal shock, pure TiC and TiC composites with 1 to 5vol%
Cr[3]C[2] additives were prepared by HP (Hot Pressing) at 2703K and
1573K, respectively, the relative densities of all the composites being
above 97%. The high-temperature deformation behavior was investigated
by means of a modified small punch testing (MSP) method at the critical
temperatures of 1208 and 1373K. Typical brittle fractures were found to
occur in all the samples at 1208K. When the testing temperature was
increased to 1373K, all the Cr[3]C[2]-doped TiC composites exhibited
obvious ductile deformation, such deformation behavior remaining
unchanged. Compared to pure TiC, the composites had lower yield
strength. The yield strength decreased and the ductile deformation
increased with increasing Cr[3]C[2] content, probably due to the
existence of lower charged Cr compounds in the composites. The
deformation transition behavior can be applied to explain the thermal
shock property of TiC/Ni[3]Al FGMs.
[TYPE]:Composite Materials
[PROP]:functionally graded material, small punch testing, high-temperature
deformation, ductility, TiC
******************************************************************************
[ID ]:KL97-192
[AUTH]:Akiyama Eiji, Kawashima Asahi, Asami Katsuhiko and Hashimoto Koji
[TITL]:An Angle-Resolved XPS Study of the In-Depth Structure of Passivated
Amorphous Aluminum Alloys
[SOUR]:Corros. Sci., 39[8] (1997), 1351-1364
[LAB ]:(2); Hashimoto; LDRAM
[ABST]:Angle-resolved X-ray photo-electron spectroscopy (ARXPS) measurements
were performed in order to characterize the in-depth structures of the
passive film and underlying alloy below the passive film for
sputter-deposited corrosion-resistant amorphous aluminum alloys.
Titanium cation is enriched throughout the passive film formed on an
amorphous Al-36Ti-7Mg alloy, while chromium cation is enriched in the
exterior of the passive film formed on an amorphous Al-36Cr-9Mo alloy
and is deficient in the interior. The analyses of the in-depth
distribution of constituents in the passive films indicate that the
field-assisted outward migration of chromium cation in the passive film
is faster than that of aluminum cations though the corrosion resistance
of chromium is apparently higher than that of aluminum in 1 M HCl. The
protective ability of the passive film is attributed to the stability
of the chromium-enriched surface layer of the passive film. The outward
migration of titanium cation is slower that of aluminum. The
investigation of the structure of the underlying alloy below the
passive film shows that chromium and titanium are enriched in the
underlying alloy surface and the composition gradually approaches the
alloy composition with depth. The thickness of the chromium- or
titanium-enriched region estimated is less than 1 nm.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:amorphous aluminum alloy, angle-resolved XPS, passive film
******************************************************************************
[ID ]:KL97-193
[AUTH]:Bitoh Teruo, Makino Akihiro, Hatanai Takashi, Inoue Akihisa and
Masumoto Tsuyoshi
[TITL]:The Relationship between the Crystallization Process and the Soft
Magnetic Properties of Nanocrystalline Fe-M-B-Cu (M=Zr,Nb) Alloy
[SOUR]:J. Appl. Phys., 81[8] (1997), 4634-4636
[LAB ]:(2); Central Res. Lab., Alps Electric Co. Ltd.; Inoue; The Res. Inst.
of Electrical and Magnetic Mater.
[ABST]:The relationship between the crystallization process and the soft
magnetic properties of nanocrystalline Fe[84]Nb[3.5]B[8]Cu[1] alloy has
been studied by comparison with that of Fe[73.5]Si[13.5]B[9]Nb[3]Cu[1]
alloy. When the annealing temperature T[a] is slightly above the
crystallization temperature, high permeability can only be obtained for
Fe-Nb-Zr-B-Cu after annealing for very short times. The T[a] dependence
of the coercive force of Fe-Nb-Zr-B-Cu cannot be explained by the
change of the bcc phase. The soft magnetic properties of Fe-Nb-Zr-B-Cu
is dominated by not only the grain size but also the Curie temperature
of the intergranular amorphous phase. It is concluded that the magnetic
softness of Fe-Nb-Zr-B-Cu is related directly to the degree of the
reduction in the apparent anisotropy, while that of Fe-Si-B-Nb-Cu is
strongly affected by the Si content of the bcc phase.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Fe-Zr-B-Cu alloy, Fe-Nb-B-Cu alloy, crystallization process, soft
magnetic properties, high permeability
******************************************************************************
[ID ]:KL97-194
[AUTH]:Chiriac Horia, Inoue Akihisa, Barariu F. and Nagacevschi V.
[TITL]:Thermoelectromotive Force of Amorphous Magnetic Fe-Cu-Nb-Si-B, Fe-Hf-B
and Fe-Zr-B Ribbons during the Crystallization Process
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 650-653
[LAB ]:(2); Inst. of Technical Phys.; Inoue
[ABST]:We present a study of the evolution of the crystallization process from
the amorphous through the nanocrystalline to the crystalline state by
measuring the temperature dependence of the thermoelectromotive force
supplied by three thermocouples of compositions
Fe[73.5]Cu[1]Nb[3]Si[13.5]B[9], Fe[90]Hf[7]B[3] and Fe[90]Zr[7]B[3].
The measurements were performed on amorphous ribbons, one portion of
the sample being crystallized by the Joule effect, during the evolution
of the crystallization process. A comparative study of the evolution of
the thermoelectromotive force for the three alloys is also presented.
The thermoelectric measurements indicate an increase in the value of
the thermoelectromotive force for all studied alloys and a change in
the sign of the Fe-Hf-B and Fe-Zr-B thermoelectromotive force.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:crystallization process, nanocrystalline materials, thermoelectric
properties
******************************************************************************
[ID ]:KL97-195
[AUTH]:El-Eskandarany M.
[TITL]:Cyclic Crystalline-Amorphous Transformations of Mechanically Alloyed
Co[75]Ti[25]
[SOUR]:Appl. Phys. Lett., 70[13] (1997), 1679-1681
[LAB ]:(1); Suzuki; Dept. of Mater. Sci., Kitami Inst. of Technol.
[ABST]:We have found that a cyclic crystalline-amorphous phase transformation
can occur in Co[75]Ti[25] alloy powder when subjected to ball milling.
The results have shown that a single amorphous phase of Co[75]Ti[25] is
obtained after 11ks of mechanical alloying (MA) time. This amorphous
phase transforms into a new metastable phase of bcc-Co[3] Ti upon
milling for 86ks. The bcc-Co[3]Ti is thermally stable and does not
transform to any other phase(s) upon heating up to 1300K. It however
returns to the same amorphous phase of Co[75]Ti[25] upon milling for
360ks. Further milling leads to the formation of crystalline and/or
amorphous phases depending on the MA time.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:cobalt-titanium alloy, mechanical alloying, phase transformation,
amorphous phase
******************************************************************************
[ID ]:KL97-196
[AUTH]:El-Eskandarany M.
[TITL]:Mechanically Induced Cyclic Crystalline-Amorphous Transformations of
Ball Milled Co[50]Ti[50] Alloy
[SOUR]:Scr. Mater., 36[9] (1997), 1001-1009
[LAB ]:(1); Suzuki; Dept. of Mater. Sci., Kitami Inst. of Technol.
[ABST]:Mechanical alloying (MA) [1] has been widely employed for preparation
of several metallic amorphous alloys [2-7] using ball milling and/or
rod milling [8] techniques. It has been reported that further milling
of amorphous Ti[75]Al[25] [9], Al[80]Fe[20] [10] Fe[78]Al[13]Si[9] [11]
and Ti[50]Al[25]Nb[25] [12] powders leads to amorphous-crystalline
transformation (crystallization): crystalline phases are formed. The
structural changes (if any) beyond this transformation has not been
reported yet. In the present work, a single amorphous phase of
Co[50]Ti[50] alloy powder is obtained after a short MA time (22ks),
using a high energy ball mill. The obtained amorphous does not
withstand against the impact and shear forces generated by the milling
media and crystallizes into bcc-Co[50]Ti[50] after further milling
(86ks). The formed crystalline phase turns to become the same amorphous
phase of Co[50]Ti[50] upon milling for 360ks. Similar to mechanical
grinding [13], this phase transformation is attributed to the
accumulation of several lattice imperfections such as point and lattice
defects, which raise the free energy from the stable phase
(bcc-Co[50]Ti[50]) to a less stable phase (amorphous). Further milling
leads to the formation of crystalline and/or amorphous phases depending
on the MA time. The present work demonstrates a cyclic
crystalline-amorphous transformations by MA.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:cobalt-titanium, mechanical milling, phase transformation, transmission
electron microscopy
******************************************************************************
[ID ]:KL97-197
[AUTH]:El-Eskandarany M.
[TITL]:Solid State Amorphization Reaction by Rod-Milling Al[x]Ta[1-x] Powders
and the Effect of Annealing
[SOUR]:Sci. Rep. RITU, A43[2] (1997), 135-143
[LAB ]:(1); Suzuki; Dept. of Mater. Sci., Kitami Inst. of Technol.
[ABST]:High thermal stable amorphous Al[x]Ta[1-x] alloy powders with wide
amorphization range (10 leq x leq 90) have been synthesized by
rod-milling technique using a mechanical alloying (MA) method. During
the first few kiloseconds (11-173ks) of the MA time, the
layered-composite particles of Al and Ta are intermixed and form an
amorphous phase upon heating at about 680K in a differential thermal
analyzer by thermally assisted solid state amorphization (TASSA). The
heat formation of an amorphous Al[x]Ta[1-x] alloy via the TASSA
process, Delta H[aT] has been measured as a function of the MA time.
The crystallization characteristics indexed by the crystallization
temperature, T[xT] and the enthalpy of crystallization, Delta H[xT] of
the amorphous phase formed via the TASSA process are also investigated
as a function of the MA time. Comparable with the TASSA process, a
homogeneous amorphous Al[x]Ta[1-x] alloy is formed after longer MA time
(1080ks). The amorphization process in this case is attributed to a
mechanical solid state amorphization (MDSSA). At the end of the MA time
(1080-1440ks), the maximum heat of formation of an amorphous
Al[x]Ta[1-x] alloy via the MDSSA process, Delta H[aM], has been
calculated. Moreover, the thermal stability characterized by the
crystallization temperature, T[xM] and the enthalpy of crystallization,
Delta H[xM], are also estimated. The role of amorphization via each
process has been discussed.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:mecahnical alloying, rod-milling, aluminum-tantalum alloy,
amorphization, crystallization
******************************************************************************
[ID ]:KL97-198
[AUTH]:El-Eskandarany M.
[TITL]:Crystalline-to-Amorphous Phase Transformation in Mechanically Alloyed
Fe[50]W[50] Powders
[SOUR]:Acta Mater., 45[3] (1997), 1175-1187
[LAB ]:(1); Suzuki
[ABST]:A mechanical alloying process via a ball milling technique has been
applied for preparing amorphous Fe[50]W[50] alloy powders. The results
have shown that during the first and second stages of milling (0 to
360ks) W atoms emigrate to Fe lattices to form nanocrystalline b.c.c.
Fe-W solid solution with a grain size of about 7nm in diameter. After
720ks of the milling time, this solid solution was transformed to an
amorphous Fe-W alloy coexisting with the residual fraction of the
unprocessed W powders. During the last stage of milling (720 to 1440ks)
all of this residual W powder reacts with the amorphous phase to form a
homogeneous Fe[50]W[50] amorphous alloy. The crystallization
temperature and the enthalpy change of crystallization of amorphous
Fe[50]W[50] powders milled for 1440ks were measured to be 860K and
-9kJ/mol, respectively. The amorphous Fe[50]W[50] powder produced is
almost paramagnetic at room temperature. The powder comprises
homogeneous and smooth spheres with an average size of about 0.5mu m in
diameter.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:iron-tangusten alloy, mechanical alloying, amorphous, phase
transformation, transmission electron microscopy, differential scanning
calorimetry
******************************************************************************
[ID ]:KL97-199
[AUTH]:Fan Cang and Inoue Akihisa
[TITL]:Improvement of Mechanical Properties by Precipitation of Nanoscale
Compound Particles in Zr-Cu-Pd-Al Amorphous Alloys
[SOUR]:Mater. Trans., JIM, 38[12] (1997), 1040-1046
[LAB ]:(2); Graduate Student, Tohoku Univ.; Inoue
[ABST]:The replacement of Cu by 10at%Pd for an amorphous Zr[60]Cu[30]Al[10]
alloy was found to change the crystallization process from the single
stage of amorphous (Am) rightarrow Zr[2]Cu+Zr[2]Al to the two stages of
Am rightarrow Am' + Zr[2](Cu, Pd) rightarrow Zr[2](Cu, Pd) + Zr[3](Al,
Pd)[2] in the maintenance of the wide super cooled liquid region before
crystallization. After the melt-spun amorphous alloys were annealed for
1.2ks at 726K and the volume fraction (V[f]) of compound reached as
large as 75%, the particle size and interparticle spacing of the
compound particles in the amorphous matrix were 10 and 1.5nm,
respectively. The residual amorphous phase enabled the maintenance of
the nanoscale compound particles. The nanoscale mixed phase alloy
remains good bending ductility even at V[f]=75% and exhibits high
tensile strength (sigma[f]) of 1910MPa which is higher than that
(1640MPa) for the amorphous single phase. The increase of the thermal
stability of the remaining amorphous phase is presumably due to the
generation of the strong bonding pair mainly among Zr, Pd and Al. The
good ductility of the mixed phase alloy is due to the suppression of
embrittlement for the remaining amorphous phase because the partial
crystallization is made in the supercooled liquid region. The first
achievement of high sigma[f] and good ductility for the mixed phase
alloy with nanoscale Zr[2](Cu, Pd) phase surrounded by the amorphous
phase is important for future progress of high-strength nanocrystalline
bulk alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:zirconium-based amorphous alloy, wide supercooled liquid region,
nanoscale mixed structure, partial crystallization, nanoscale compound
particle, dispersion hardening, high tensile strength
******************************************************************************
[ID ]:KL97-200
[AUTH]:Haruyama Osami, Kimura Hisa Michi and Inoue Akihisa
[TITL]:Thermal Stabilities of Some Glassy Metals with a Wide Supercooled
Liquid Region
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 209-212
[LAB ]:(1); Dept. of Phys., Sci. Univ. of Tokyo; LDRAM; Inoue
[ABST]:The thermal stability of a Zr[60]Al[15]Ni[25] glassy metal was
investigated mainly by electrical measurements. In particular,
attention was paid to the influence of thermal histories, i.e., the
sample preparation condition and the atmosphere during measurement of
physical properties. The glass-transition phenomenon was distinctly
detected from the change in the electrical resistance with increasing
temperature. The electrical resistance behavior of a Pd[58]Ni[25]Si[17]
glassy metal around its glass-transition temperature was also examined
for comparison. A similar change in the electrical resistance
associated with the glass transition was also observed for this
Pd-based glassy metal. It is, therefore, presumed that the electron
transport property changes around the glass-transition temperature.
Both the glass-transition temperature and the crystallization
temperature were almost independent of the thermal history of their
samples. However, the temperature derivative of the electrical
resistance is significantly dependent on the thermal history.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:bulk amorphous alloy, Glassy metal, supercooled liquid region, thermal
stability
******************************************************************************
[ID ]:KL97-201
[AUTH]:Haruyama Osami, Kimura Hisa Michi, Aoki Takahiro, Nishiyama Nobuyuki
and Inoue Akihisa
[TITL]:Thermal Stability of Pd-Based Metallic Glasses Examined by Electrical
Resistance Measurement
[SOUR]:Sci. Rep. RITU, A43[2] (1997), 97-100
[LAB ]:(1); Dept. of Phys., Faculty of Sci. and Technol., Sci. Univ. of Tokyo;
LDRAM; Hiranuma Industry Co. Ltd.; Teikoku Piston Ring Co. Ltd.; Inoue
[ABST]:Thermal stability of some Pd-based metallic glasses was investigated
mainly by the electrical resistance measurement. Differential thermal
analysis was also performed to compare the thermogram with the
electrical resistance curve. The crystallization and glass transition
temperatures were in good agreement between both measurements. The
influence of gas atmosphere on the electrical resistance curve was
examined under a purified Ar and a vacuum state. The amount of oxygen
impurity was larger for Ar than vacuum. From the electrical resistance
behavior in the supercooled liquid region it was concluded that the
thermal stability of metallic glasses which contain Pd and/or B atoms
was obviously affected by the oxygen impurity in the Ar atmosphere.
Samples which were annealed to a temperature in the supercooled liquid
region under an Ar atmosphere showed the precipitation of
nano-crystallites.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:palladium-based alloys, metallic glass, thermal stability, electrical
resistance, oxygen impurity
******************************************************************************
[ID ]:KL97-202
[AUTH]:Hashimoto Koji, Zhang Bo Ping, Im Byung Mo, Lee Ho Jin, Akiyama Eiji,
Habazaki Hiroki, Kawashima Asahi and Asami Katsuhiko
[TITL]:The Role of Phosphorus in Enhancing Corrosion Resistance of Amorphous
Alloys
[SOUR]:Sci. Rep. RITU, A43[2] (1997), 145-151
[LAB ]:(2); Hashimoto; LDRAM
[ABST]:Phosphorus contained in amorphous metal-metalloid alloys is often
beneficial in enhancing the corrosion resistance particularly in strong
acids. On the basis of investigations conducted so far, the beneficial
role of phosphorus is comprehensively summarized. Immersion of
amorphous metal-phosphorus alloys containing passivating elements leads
to the formation of elemental phosphorus layer on the topmost surface
of the alloy as a result of initial alloy dissolution. The elemental
phosphorus layer has high cathodic activity for oxygen and proton
reduction and acts as the diffusion barrier against alloy dissolution.
These beneficial effects ennoble the open circuit potential, and when
the open circuit potential attains the passive region of t he alloy
spontaneous passivation occurs. An increase in the protectiveness of
the passive film by ageing further ennobles the open circuit potential.
At the high open circuit potential elemental phosphorus is no longer
stable and dissolves into the solution. The passive film thus formed
generally consists of passive oxyhydroxide and the phosphorus content
in the film is rather low.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:amorphous alloy, phosphorus, corrosion resistance, passivation
******************************************************************************
[ID ]:KL97-203
[AUTH]:Hono Kazuhiro, Zhang Y.
[TITL]:APFIM Studies on Nanocrystallization of Amorphous Alloys
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 498-502
[LAB ]:(2); National Res. Inst. for Met.; Sakurai; Inoue
[ABST]:This paper reports recent atom probe analysis results of Fe-Zr-B(-Cu,
Si, Al) and Al-Ni-Ce(-Cu) nanocrystalline alloys which are fabricated
by primary crystallization of amorphous phase. Clustering, partitioning
and segregation of alloying elements in the course of primary
crystallization have been thoroughly studied by atom probe field ion
microscopy (APFIM). Mechanisms of nanocrystallization in these systems
are discussed based on these results.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:APFIM, nanocrystallization, amorphous
******************************************************************************
[ID ]:KL97-204
[AUTH]:Illekova Emilia, Jergel Matej, Duhaj Pavol and Inoue Akihisa
[TITL]:The Relation between the Bulk and Ribbon Zr[55]Ni[25]Al[20] Metallic
Glasses
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 388-392
[LAB ]:(2); Inst. of Phys., Slovak Acad. of Sci.; Inoue
[ABST]:The planar-flow-casting technique and quenching in flowing water were
used to produce the glassy Zr[55]Ni[25]Al[20] ribbon and bulk samples.
The thermodynamic states of these two types of samples were compared
using differential scanning calorimetry and analysis of the structural
relaxation kinetics. The relaxation enthalpy is 3 times larger and the
glass transition temperature is higher by 67.5K in the case of the
ribbon samples. These differences were theoretically confirmed by a
kinetic model and were caused by the different quenching rates for the
ribbon and bulk samples, namely 10]5[ and 10]2[ Ks]-1[, respectively.
X-ray analysis has shown, that the main difference between the studied
glassy structures consists in the different degree of the short-range
order in the samples.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:differential scanning calorimetry, metallic glasses, structural
relaxation kinetics
******************************************************************************
[ID ]:KL97-205
[AUTH]:Inoue Akihisa
[TITL]:Bulk Amorphous Alloys with Soft and Hard Magnetic Properties
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 357-363
[LAB ]:(3); Inoue
[ABST]:This paper reviews our recent findings of bulk amorphous alloys with
soft or hard magnetism at room temperature. Soft magnetic
characteristics combined with large glass-forming ability (GFA) were
obtained in Fe[72]Al[5]Ga[2]P[11]C[6]B[4] and
Fe[72]Al[5]Ga[2]P[10]C[6]B[4]Si[1] amorphous alloys. The maximum
thickness for glass formation by copper mold casting was about 3mm.
These bulk amorphous alloys have a Curie temperature(T[c]) of 600-606K
in an annealed state and their soft magnetic properties are about 1.1T
for saturation magnetization (B[s]) and 2-6 A m]-1[ for coercive force
(H[c]). The thick amorphous sheets up to 180mu m in thickness exhibit
high permeability of 7000-12000 at 1kHz. On the other hand, the hard
magnetic properties were obtained for amorphous Ln[60]Fe[30]Al[10]
(Ln=Nd or Pr) cylinders with diameters below 15mm. The large GFA is due
to the high T[x]/T[m] of 0.85-0.90 and the small temperature intervals
of 85-140K between T[m] and T[x]. The T[c] is around 600K and typical
magnetic properties are 0.13T for remanence, 0.15T for B[s], 280kA
m]-1[ for H[c] and 19kJ m]-3[ for (JH)[max]. The hard magnetic
properties disappear in the crystallized state. The first success of
synthesizing the ferromagnetic bulk amorphous alloys is important for
future progress of basic science and applications.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:ferromagnetic bulk amorphous alloy, Fe-based system, Nd-based system,
soft magnetic property, hard magnetic property
******************************************************************************
[ID ]:KL97-206
[AUTH]:Inoue Akihisa
[TITL]:Stabilization of Supercooled Liquid and Opening-up of Bulk Glassy
Alloys
[SOUR]:Proc. Jpn. Acad. B, 73[2] (1997), 19-24
[LAB ]:(3); Inoue
[ABST]:Bulk glassy alloys with thicknesses up to 75mm and a wide supercooled
liquid region reaching 127K before crystallization were found to be
fabricated in a number of multicomponent systems which satisfy the
three empirical rules for the achievement of large glass-forming
ability, i.e., (1) multicomponent alloy systems consisting of more than
three constituent elements, (2) significantly different atomic size
ratios above 12%, and (3) negative heats of mixing. The scientific
significance of the rules has been proved based on a number of
experimental data as well as on the kinetic theories of the nucleation
and growth of a crystalline phase. By choosing appropriate compositions
which satisfy the empirical rules, bulk glassy alloys in Mg-,
lanthanide metal-, Zr-, Pd-, Fe- and Co-based systems were produced in
cylindrical and sheet forms by various solidification processes. The
bulk glassy alloys exhibit high tensile strength, good ductility, high
elastic energy, high impact fracture energy and high corrosion
resistance for Zr-based system and good soft magnetic properties for
Fe-based system. Furthermore, their glassy alloys heated in the
supercooled liquid region can be deformed into various shapes through
viscous flow. The ideal Newtonian flow has been achieved in the
supercooled liquid. The utilization of the ideal superplasticity
enabled the achievement of an extremely large elongation exceeding
15000%. These excellent data allow us to expect that the bulk glassy
alloys develop as anew type of engineering material.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:bulk glassy alloy, stabilized supercooled liquid, glass transition,
large glass-forming ability, low critical cooling rate
******************************************************************************
[ID ]:KL97-207
[AUTH]:Inoue Akihisa and Nishiyama Nobuyuki
[TITL]:Extremely Low Critical Cooling Rates of New Pd-Cu-P Base Amorphous
Alloys
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 401-405
[LAB ]:(3); Inoue
[ABST]:A new Pd[40]Ni[10]Cu[30]P[20] amorphous alloy subjected to the B[2]O[3]
flux treatment was found to have a maximum thickness above 50 mm and a
low critical cooling (R[c]) of 0.100Ks]-1[. The R[c] for the Pd-Ni-Cu-P
alloy without the flux treatment is 1.58Ks]-1[ and the decrease in R[c]
is due to the suppression of heterogeneous nucleation, in addition to
the high T[g]/T[m] of 0.72 and Delta T[x](=T[x]-T[g]) of 98K. These
R[c] values are smaller and the T[g]/T[m] and Delta T[x] values are
larger as compared with those (R[c]=140Ks]-1[), T[g]/T[m]=0.67 and
Delta T[x]=63K) for an unfluxed Pd[40]Ni[40]P[20] amorphous alloy. The
new alloy appears to lie around the eutectic point with a low T[m] of
804K and the crystallization occurs through a single stage accompanying
the precipitation of Pd[2]Ni[2]P, Pd[15]P[2], (Ni, Cu)[3]P and unknown
compound. The finding of the new amorphous alloy with the lowest R[c]
and the largest thickness is important for the future development of
bulk amorphous alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:bulk amorphous alloy, low critical cooling rate, large thickness, flux
treatment, single-stage crystallization
******************************************************************************
[ID ]:KL97-208
[AUTH]:Inoue Akihisa and Zhang Tao
[TITL]:Novel Superplasticity of Supercooled Liquid for Bulk Amorphous Alloys
[SOUR]:Mater. Sci. Forum, 243-245 (1997), 197-206
[LAB ]:(3); Inoue
[ABST]:The finding of new bulk amorphous alloys with large glass-forming
ability and wide supercooled liquid region before crystallization has
enabled the research on the deformation behavior of the supercooled
liquid. As a result, it was found that the supercooled liquid has a
high strain-rate sensitivity exponent of 1.0, extremely large
elongations reaching about 150000 % and ultrahigh strain-rate
superplasticity of 1 times 10]6[ s]-1[ which have not been obtained for
any crystalline alloys. The excellent superplastic characteristics are
promising for future development as a new type of superplastic metallic
material.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:bulk amorphous alloy, glass transition, supercooled liquid,
superplasticity, zirconium-based alloy
******************************************************************************
[ID ]:KL97-209
[AUTH]:Inoue Akihisa and Zhang Tao
[TITL]:Thermal Stability and Glass-Forming Ability of Amorphous Nd-Al-TM
(TM=Fe, Co, Ni or Cu) Alloys
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 393-396
[LAB ]:(3); Inoue
[ABST]:Bulk amorphous alloys were prepared for Nd[70]Al[10]TM[20] and
Nd[60]Al[10]TM[30] (TM=Fe or Co) alloys by copper mold casting. The
maximum sample thickness for glass formation reaches 15mm for the
Nd-Al-Fe alloys and 5mm for the Nd-Al-Co alloys. A significant
difference in the phase transition upon heating is recognized between
the Fe- and Co-containing alloys. No glass transition before
crystallization is observed for the Nd-Al-Fe alloys, but the Nd-Al-Co
alloys exhibit the glass transition. The Delta T[x](=T[x]-T[g]) and
T[g]/T[m] are 40-55K and 0.65-0.67, respectively, for the latter
alloys. The absence of supercooled liquid for the former alloys is
different from those for all bulk amorphous alloys reported up to date.
The T[x]/T[m] and Delta T[m](=T[m]-T[x]) are 0.85-0.89 and 88-137K,
respectively, for the Nd-Al-Fe alloys and, hence, the large
glass-forming ability is presumably due to the high T[x]/T[m] and small
Delta T[m] values.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:bulk amorphous alloy, high reduced crystallization temperature, glass
transition, supercooled liquid
******************************************************************************
[ID ]:KL97-210
[AUTH]:Inoue Akihisa, Aoki Takahiro and Kimura Hisamichi
[TITL]:Effect of B Addition on Extension of Supercooled Liquid Region before
Crystallization in Pd-Cu-Si Amorphous Alloys
[SOUR]:Mater. Trans., JIM, 38[2] (1997), 175-178
[LAB ]:(2); Inoue; Hiranuma Industry Co. Ltd.; LDRAM
[ABST]:The supercooled liquid region defined by the difference between glass
transition temperature (T[g]) and crystallization temperature (T[x]),
Delta T[x](=T[x]-T[g]) for a Pd[76]Cu[6]Si[18] amorphous alloy was
found to be significantly extended by the replacement of 3at%B for Si.
The replacement causes a decrease in T[g] and an increase in T[x],
leading to the maximum value of 70K for Delta T[x]. The
Pd[76]Cu[6]Si[15]B[3] alloy crystallizes through a single-stage
exothermic reaction which leads to simultaneous precipitation of
Pd[4]Si, Pd[3]Si and Pd[2] phases. With further increasing replacement
amount of B, the Delta T[x] decreases significantly, accompanying the
change in the crystallization mode to two stages including the primary
precipitation of metastable supersaturated Pd solid solution. The
crystallized structure after the two-stage reaction for the
Pd[76]Cu[6]Si[13]B[5] alloy consists of five phases of Pd, Pd[4]Si,
Pd[3]Si, Pd[2]Si and Pd[2]B. By the dissolution of an appropriate
amount (about 3at%) of B element with smaller atomic size and negative
heats of mixing against the other constituent elements, the amorphous
structure is presumed to change into a higher degree of dense random
packed state. As a result, the long-range atomic rearrangement for
crystallization required for the precipitation of the three compound
phases in the single-stage exothermic reaction becomes difficult,
leading to the extension of the supercooled liquid region. The increase
in the thermal stability of the supercooled liquid in the
Pd[76]Cu[6]Si[15]B[3] amorphous alloy is important because of the
increase in the ease of the formation of bulk amorphous alloy.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:palladium-copper-silicon-boron alloy, amorphous phase, supercooled
liquid region, glass transition, single-stage crystallization, multiple
crystalline phases
******************************************************************************
[ID ]:KL97-211
[AUTH]:Inoue Akihisa, Kawamura Yoshihito and Saotome Yasunori
[TITL]:High Strain Rate Superplasticity of Supercooled Liquid for Amorphous
Alloys
[SOUR]:Mater. Sci. Forum, 233-234 (1997), 147-154
[LAB ]:(2); Inoue; Faculty of Eng., Gunma Univ.
[ABST]:The recent discoveries of a number of new amorphous alloys with a wide
supercooled liquid region before crystallization have enabled the
progresses of basic science and engineering utilization of the
supercooled liquid. The supercooled liquid has a high strain rate
sensitivity (m-value) of 1.0, implying the achievement of an ideal
superplasticity. Furthermore, the high m-value was found to cause
extremely large tensile elongations of about 1.5 times 10]5[ % at
ordinary strain rates of 10]-2[ to 10]-1[ s]-1[ and large compressive
elongations reaching nearly 100% at the ultrahigh strain 10]-2[ to
10]-1[ s]-1[ and large compressive elongations reaching nearly 100% at
the ultrahigh strain rate of 10]-6[ s]-1[. he appearance of the
extremely large elongations and the ultrahigh strain rate
superplasticity which have not been obtained for crystalline
superplastic alloys is promising for future development of the
supercooled liquid to produce superplastic materials with various
shapes.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:amorphous alloy, supercooled liquid, viscous flow, superplastic, high
strain rate deformation
******************************************************************************
[ID ]:KL97-212
[AUTH]:Inoue Akihisa, Kimura Hisa Michi and Kita Kazuhiko
[TITL]:Development of High-Specific Strength Al-Based Alloys by Utilizing
Nanogranular Quasicrystalline Phases
[SOUR]:New Horizons in Quasicrystals: Research and Applications, Ames, Iowa,
1996, ed. by A.I. Goldman, et al., (1997), 256-263
[LAB ]:(2); Inoue; LDRAM; YKK R&D Div.
[ABST]:This paper reviews our recent results on the development of
high-strength Al- based alloys through the formation of a new type
structure of nanoscale icosahedral (I)+fcc-Al phases. In the Al-based
alloys containing the I-forming elements, a new mixed structure
consisting of the nanoscale I particles surrounded by Al phase was
formed in the melt-spun Al-Mn-Ln and Al-Cr-Ln (Ln=lanthanide metal)
alloys. The formation of the mixed structure results from the unique
solidification process in which the I-phase precipitates as a primary
phase, followed by the solidification of the remaining liquid as the
surrounding Al phase. The grain size is 10 to 50nm for the I phase and
about 10nm for the Al phase. These mixed phase alloys have good bending
ductility and exhibit high sigma[f] of 1200 to 1400MPa which are higher
than the highest sigma[f](equiv 1200MPa) for Al-rich amorphous alloys.
In addition, the bulk I base alloys were also produced by extruding
atomized I-based powders and exhibited high sigma[f] of 500 to 880MPa
combined with large elongations of 7 to 24 %. The new mixed structure
and good mechanical properties are attractive enough to allow the
expectation of future development as a new type of strengthening
material.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:aluminum base alloy, quasicrystalline, nanogranular, high strength,
extrusion
******************************************************************************
[ID ]:KL97-213
[AUTH]:Inoue Akihisa, Kimura Hisa Michi and Sasamori Kenichiro
[TITL]:High-Strength Al[94](V, Ti)[4]Fe[2] Alloys Consisting of Nanogranular
Amorphous and fcc-Al Phases
[SOUR]:Nanostruct. Mater., 9 (1997), 493-496
[LAB ]:(2); Inoue; LDRAM; Gijutsu
[ABST]:Nanogranular amorphous (Am) phase with a grain size of 7nm was formed
in coexistence with fcc-Al phase in melt-spun Al[94]V[4-x]Ti[x]Fe[2]
(x=0 to 3at%) alloys. The formation of the Am phase is due to the
solidification process of liquid(L) ¨ primary Am + remaining L ¨ Am +
Al resulting from the suppression of the precipitation from liquid to
icosahedral (I) phase. The Am + Al alloys exhibit high tensile strength
(sigma[f]) of 1400MPa. The nanogranular Am phase is important for the
development of high strength materials through the formation of
nonequilibrium phases.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Al-based alloy, high-strength material, rapid solidification,
nanogranular amorphous phase, icosahedral phase
******************************************************************************
[ID ]:KL97-214
[AUTH]:Inoue Akihisa, Kimura Hisa Michi, Watanabe Mitsuru and Kawabata Akihiko
[TITL]:Work Softening of Aluminum Base Alloys Containing Nanoscale Icosahedral
Phase
[SOUR]:Mater. Trans., JIM, 38[9] (1997), 756-760
[LAB ]:(1); Inoue; LDRAM; Faculty of Mineral and Mining, Akita Univ.
[ABST]:Melt-spun Al[93]Mn[5]Ce[2], Al[92]Mn[6]Ce[2] and Al[94.5]Cr[3]Co[1.5]
ribbons consist of nanoscale icosahedral (I) particles surrounded by
fcc-Al phase without grain boundaries. The ribbons were cold rolled to
70% reduction in thickness (R[e]) and the rolling causes significant
decreases in hardness and tensile strength. The particle size and
interparticle spacing of the I-phase decrease by rolling, accompanying
the increase in the area of the I/Al interface. However, no dislocation
was observed in the cold-rolled Al and I phases. The absence of
dislocations is because the interface acts as a sink of dislocations,
leading to the work-softening. The softening phenomenon reflects an
inverse Hall-Petch relation in which the yield strength and hardness
decrease with decreasing grain size in the size region below about 30
nm because the interparticle spacing of the I-phase decreases from
15-25nm to 5-10nm by cold rolling to 30 to 70% reduction in thickness.
This phenomenon is important for better understanding of deformation
and strengthening mechanisms of the nanostructure alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:icosahedral base alloy, nanoscale icosahedral particle, rapid
solidification, aluminum base alloy, cold rolling
******************************************************************************
[ID ]:KL97-215
[AUTH]:Inoue Akihisa, Koshiba Hisato, Zhang Tao and Makino Akihiro
[TITL]:Thermal and Magnetic Properties of Fe[56]Co[7]Ni[7]Zr[10-x]Nb[x]B[20]
Amorphous Alloys with Wide Supercooled Liquid Range
[SOUR]:Mater. Trans., JIM, 38[7] (1997), 577-582
[LAB ]:(2); Inoue; Alps Electric Co. Ltd.
[ABST]:Amorphous alloys with a wide supercooled liquid region of 45 to 85K
were found to be formed in Fe[56]Co[7]Ni[7]Zr[10-x]Nb[x]B[20](x=0 to
10at%) alloys by melt spinning. The glass transition temperature (T[g])
and the crystallization temperature (T[x]) increase by the dissolution
of 2 to 4%Nb. The degree of increase is larger for T[x] than T[g],
leading to the maximum Delta T[x](=T[x]-T[g]) of 85K for the 2%Nb
alloy. The Delta T[x] value is about 20K larger than the largest value
for the newly developed Fe-(Al, Ga)-(P, C, B, Si) amorphous alloys. The
crystallization occurs through a single stage, amorphous ¨
alpha-Fe+gamma-Fe+Fe[2]Zr+Fe[76]Nb[6]B[18], for the alloys containing
less than about 6%Nb and through two stages, amorphous ¨
amorphous+gamma-Fe ¨ gamma-Fe+Co[3]Nb[2]B[5]+Ni[8]Nb, for the alloys
containing more than 8%Nb. The change in the crystallization process
for the Nb-rich alloys probably reflects the disappearance of Fe[2](Nb,
Zr) precipitates because of the weaker bonding of Fe-Nb pair as
compared with Fe-Zr one. As the Nb content increases, the saturation
magnetization (I[s]) and permeability (mu[e]) of the annealed alloys
decrease while the coercive force (H[c]) remains almost unchanged. The
good soft magnetic properties are obtained for the alloys containing
less than 2%Nb subjected to annealing for 300s at 800K and the I[s],
H[c] and mu[e] at 1kHz are 0.96T, 2.0A/m and 19100, respectively, for
the 0%Nb alloy and 0.75T, 1.1A/m and 25000, respectively, for the 2%Nb
alloy. The success of synthesizing the new amorphous alloys with a wide
supercooled liquid region more than 80K and with good soft magnetic
properties is promising for future development as soft magnetic bulk
amorphous alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:iron-based alloy, soft magnetic alloy, glass transition, wide
supercooled liquid region, melt spinning
******************************************************************************
[ID ]:KL97-216
[AUTH]:Inoue Akihisa, Makino Akihiro and Mizushima Takao
[TITL]:Soft Magnetic Properties of Fe Based Amorphous Thick Sheets with Large
Glass Forming Ability
[SOUR]:J. Appl. Phys., 81[8] (1997), 4029-4031
[LAB ]:(2); Inoue; Central Res. Lab., Alps Electric Co. Ltd.
[ABST]:The thermal stability of the supercooled liquid, glass forming ability
(GFA) and magnetic properties were examined for amorphous
Fe[72-x]Al[5]Ga[2]P[11]C[6]B[4]Si[x], Fe[72]Al[5]Ga[2]P[11-x]C[6]B[4]Si
[x] and Fe[72]Al[5]Ga[2]P[11]C[6-x]B[4]Si[x] alloys. The increases in
the thermal stability and GFA and the improvement of the soft magnetic
properties were recognized in the replacements of P by 1 to 2at.%Si and
of C by 1at.%Si. The supercooled liquid region Delta T[x] defined by
the difference between T[x] and T[g] increases from 53K for
Fe[72]Al[5]Ga[2]P[11]C[6]B[4] to 58K for
Fe[72]Al[5]Ga[2]P[11]C[5]B[4]Si[1]. The maximum thickness for glass
formation (t[max]) by copper mold casting also increases from 1mm for
the Fe-Al-Ga-P-C-B alloy to 3mm for the
Fe[72]Al[5]Ga[2]P[10]C[6]B[4]Si[1] alloy. The increases in Delta T[x]
and t[max] are presumably because of the increase in the degree of the
satisfaction of the three empirical rules for glass formation. The soft
magnetic properties are also improved by the replacement of 1%Si
through the increase in the squareness ratio of B-H loop (B[r]/B[s])
and the decrease in coercive force (H[c]). The best soft magnetic
properties for the bulk amorphous alloys are 1.14T for Bs, 1.5A/m for
H[c], 0.45 for B[r]/B[s] and 594K for T[c] for the
Fe[72]Al[5]Ga[2]P[10]C[6]B[4]Si[1] alloy. The success of forming the Fe
based ferromagnetic bulk amorphous alloys of 3mm in thickness is
promising for future development as a new type of magnetic material.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Fe-based alloy, amorphous thick sheet, soft magnetic property, large
glass-forming ability, bulk amorphous alloy
******************************************************************************
[ID ]:KL97-217
[AUTH]:Inoue Akihisa, Mizushima Takao and Makino Akihiro
[TITL]:Preparation of Thick Amorphous Alloy Sheets in Multicomponent Fe-based
Systems and Their Thermal and Magnetic Properties
[SOUR]:Sci. Rep. RITU, A43[2] (1997), 115-121
[LAB ]:(2); Inoue; Central Res. Lab., Alps Electric Co. Ltd.
[ABST]:Thick amorphous sheets with thickness up to about 200mu m were formed
for the Fe[72]Al[5]Ga[2]P[10]C[6]B[4]Si[1] alloy with a wide
supercooled liquid region of 58K before crystallization. The glass
transition temperature (T[g]), crystallization temperature (T[x]) and
supercooled liquid region Delta T[x](=T[x]-T[g]) remain unchanged in
the entire thickness range. However, the heat of structural relaxation
decreases from 2.2kJ/mol for the 22mu m thick ribbon to 0.48kJ/mol for
the 160mu m thick ribbon, accompanying the increase in T[c] from 597K
to 619K. In comparison with the other amorphous alloy ribbons in the
same Fe-(Al, Ga)-(P, C, B, Si) system, there is a clear tendency for
the maximum sample thickness for glass formation (t[max]) to increase
with increasing Delta T[x]. The Fe-Al-Ga-P-C-B-Si amorphous sheets have
high saturation magnetization of about 180 times 10]-6[Wbm/kg and low
coecivity of about 5A/m in the annealed state and their values remain
unchanged in the thickness range up to 200mu m. The permeability
(mu[e]) at 1 kHz shows the high values of 12000 for the 30mu m thick
ribbon and decreases to about 7000 for the 200mu m thick ribbon. It is
to be noticed that the good soft magnetic properties of 5A/m for H[c]
and 7000 for mu[e] as well as the wide supercooled liquid region of 58K
are obtained for the thick amorphous sheets with thickness of 150 to
200mu m. These characteristics for the thick amorphous ribbons have not
been obtained for Fe-based amorphous alloys previously reported. It is
therefore expected that the thick amorphous ribbons cause a further
extension of the application fields of ferromagnetic amorphous alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:ferromagnetic glassy alloy, rapid solidification, wide supercooled
liquid region, soft-magnetic property, sample thickness
******************************************************************************
[ID ]:KL97-218
[AUTH]:Inoue Akihisa, Murakami Akira, Zhang Tao and Takeuchi Akira
[TITL]:Thermal Stability and Magnetic Properties of Bulk Amorphous
Fe-Al-Ga-P-C-B-Si Alloys
[SOUR]:Mater. Trans., JIM, 38[3] (1997), 189-196
[LAB ]:(3); Inoue
[ABST]:The effect of Si additions on the thermal stability of the supercooled
liquid before crystallization, glass-forming ability (GFA) and soft
magnetic properties was examined for amorphous alloy series
Fe[72-x]Al[5]Ga[2]P[11]C[6]B[4]Si[x], Fe[72]Al[5-x]Ga[2]P[11]C[6]B[4]Si
[x], Fe[72]Al[5]Ga[2]P[11-x]C[6]B[4]Si[x] and
Fe[72]Al[5]Ga[2]P[11]C[6-x]B[4]Si[x]. The increases in the thermal
stability and GFA and the improvement of soft magnetic properties were
recognized in the replacements of P by 1 to 2at%Si and of C by 1at%Si.
The supercooled liquid region (Delta T[x]) defined by the difference
between crystallization temperature (T[x]) and glass transition
temperature (T[g]) increases from 53K for Fe[72]Al[5]Ga[2]P[11]C[6]B[4]
to 58K for Fe[72]Al[5]Ga[2]P[11]C[5]B[4]Si[1]. The maximum thickness
for glass formation (t[max]) by copper mold casting increases from 1 mm
for the Fe-Al-Ga-P-C-B alloy to 2mm for the
Fe[72]Al[5]Ga[2]P[10]C[6]B[4]Si[1] alloy. The increases in Delta T[x]
and t[max] are presumably because of the increase in the degree of the
satisfaction of the three empirical rules for the achievement of large
glass-forming ability, i.e., (1) multicomponent alloy systems
consisting of more than three elements, (2) significantly different
atomic size ratios above about 12% and (3) negative heats of mixing.
The soft magnetic properties are also improved by the replacement of
1at%Si for P or C through the increase in the squareness ratio of B-H
loop (B[r]/B[s]) and the decrease in coercive force (H[c]). The best
soft magnetic properties for the bulk amorphous alloys are obtained for
the Fe[72]Al[5]Ga[2]P[10]C[6]B[4]Si[1] alloy and the saturation
magnetization (B[s]), H[c], B[r]/B[s], and Curie temperature are 1.14T,
1.5A/m, 0.45 and 594K, respectively. The success of forming the
Fe-based bulk amorphous alloys of 2mm in thickness exhibiting the good
soft magnetic properties is promising for future development as a new
type of soft magnetic material.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:ferromagnetic bulk amorphous alloy, iron-based alloy, large
glass-forming ability, copper mold casting, glass transition
******************************************************************************
[ID ]:KL97-219
[AUTH]:Inoue Akihisa, Negishi Tadahiro, Kimura Hisa Michi and Aoki Takahiro
[TITL]:Effect of B Addition on the Extension of Supercooled Liquid Region in
Zr-Cu-Al Base Amorphous Alloys
[SOUR]:Mater. Trans., JIM, 38[3] (1997), 185-188
[LAB ]:(2); Inoue; Otsuka Manufacturing Co. Ltd.; LDRAM; Hiranuma Industry Co.
Ltd.
[ABST]:The replacement of Al by B for Zr[65]Cu[27.5]Al[7.5-x]B[x] amorphous
alloys was found to cause an extension of the supercooled liquid region
before crystallization. The largest value of the supercooled liquid
region (Delta T[x]) defined by the difference between crystallization
temperature (T[x]) and glass transition temperature (T[g]) is 100K for
Zr[65]Cu[27.5]B[4]Al[3.5]. The Delta T[x] value is much larger than
that (72K) for the Zr[65]Cu[27.5]Al[7.5] alloy. The increase is due to
the significant increase in T[x] by the addition of B exceeding the
degree of the increase in T[g]. The crystallization from the
supercooled liquid takes place through a single exothermic reaction in
the B concentration range less than 4at%. The crystallized structure
consists of Zr[2]Cu, Zr[2]Al and Zr[5]Al[3] for the Zr-Cu-Al alloy and
changes into more multiple phases of Zr[2]Cu, Zr[2]Al, Zr[3]Al,
Zr[5]Al[3] and ZrB[2] for the Zr[65]Cu[27.5]B[4]Al[3.5] alloy. Besides,
the temperature dependence of the storage and loss moduli (E' and E")
in the supercooled liquid also changes from the single stage for the
Zr-Cu-Al alloy to the two stages for the Zr-Cu-Al-B alloy. The
first-stage changes in the E'(T) and E"(T) fit between both alloys and
the second-stage change for the B-containing alloy takes place in the
temperature range above T[x] of the Zr-Cu-Al ternary alloy. It is
therefore concluded that the generation of Zr-B atomic pair with
stronger bonding nature and longer relaxation time by the addition of B
causes the increase in the thermal stability of supercooled liquid
region through the retardation of the crystallization reaction.
Furthermore, this is the first evidence on the synthesis of the
amorphous alloy with the large Delta T[x] above 100K for the Zr-Cu-B-Al
alloy containing higher B content as compared with Al content.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:zirconium-copper-boron base amorphous alloy, bulk amorphous alloy,
glass transition, wide supercooled liquid region, long relaxation time
******************************************************************************
[ID ]:KL97-220
[AUTH]:Inoue Akihisa, Nishiyama Nobuyuki and Kimura Hisa Michi
[TITL]:Preparation and Thermal Stability of Bulk Amorphous
Pd[40]Cu[30]Ni[10]P[20] Alloy Cylinder of 72 mm in Diameter
[SOUR]:Mater. Trans., JIM, 38[2] (1997), 179-183
[LAB ]:(2); Inoue; Graduate Student, Tohoku Univ.; LDRAM
[ABST]:The glass-forming ability of a Pd[40]Cu[30]Ni[10]P[20] alloy was found
to increase significantly by B[2]O[3] flux treatment, as is evidenced
by the decrease in the critical cooling rate from 1.57K/s in the
non-fluxed state to 0.100K/s in the fluxed state. The flux treatment
also causes the extension of the supercooled liquid region by the
increase in the onset temperature of crystallization (T[x]). The effect
of the flux treatment is presumably due to the increase in the thermal
stability of the supercooled liquid by the suppression of heterogeneous
nucleation. The critical cooling rates in the non-fluxed and fluxed
states for a Pd[40]Ni[40]P[20] alloy are measured to be 128 and
0.167K/s, respectively, both of which are larger than those for the
Pd-Cu-Ni-P alloy. The use of the molten Pd-Cu-Ni-P alloy subjected to
the flux treatment enabled the production of bulk amorphous alloys in
cylindrical forms of 50 to 72mm in diameter and 52 to 75mm in length.
The glass transition temperature (T[g]) and T[x] values of the bulk
amorphous alloys are the same as those for the melt-spun amorphous
ribbon prepared from the fluxed molten alloy. The success of
synthesizing an amorphous alloy of 72mm in diameter is encouraging both
for the future development of basic science of bulk amorphous alloys
and for their engineering application.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:bulk amorphous alloy, palladium-copper-phosphorus base system, B[2]O[3]
flux treatment, glass-forming ability, glass transition
******************************************************************************
[ID ]:KL97-221
[AUTH]:Inoue Akihisa, Zhang Tao and Kim Yeong Hwan
[TITL]:Synthesis of High Strength Bulk Amorphous Zr-Al-Ni-Cu-Ag Alloys with a
Nanoscale Secondary Phase
[SOUR]:Mater. Trans., JIM, 38[9] (1997), 749-755
[LAB ]:(2); Inoue; Dept. of Metall. Eng., Pusan National Univ.
[ABST]:Bulk amorphous alloys in a cylindrical form were prepared in the
diameter range up to about 5 mm for Zr[65]Al[7.5]Ni[10]Cu[17.5-x]Ag[x]
(x=0 to 5 at%) by copper mold casting. These bulk amorphous alloys
exhibit a wide supercooled liquid region before crystallization and the
temperature interval defined by the difference between glass transition
temperature (T[g]) and crystallization temperature (T[x]), Delta
T[x](=T[x]-T[g]) is 111K for the 0%Ag alloy and 63K for the 5%Ag alloy.
The replacement of Cu by 5at%Ag causes the change in the
crystallization process from a single stage of Am rightarrow Zr[2](Cu,
Ni)+Zr[2](Al, Ni) to two stages of Am rightarrow Am'+Zr[3](Al, Ag)[2]
rightarrow Zr[3](Al, Ag)[2]+Zr[2](Cu, Ni). The Zr[3](Al, Ag)[2] phase
has a spherical shape with a small size of about 20nm and is dispersed
homogeneously at an interparticle spacing of about 30nm. The change in
the crystallization process by the addition of Ag is presumably due to
the generation of the distinction of bonding nature among the
constituent elements because of the positive heats of mixing for Ag-Ni
and Ag-Cu pairs. The dispersion of the nanoscale Zr[3](Al, Ag)[2] phase
causes a significant increase in tensile fracture strength (sigma[f])
from 1150MPa for the amorphous single phase to 1520MPa for the
amorphous phase containing about 14% volume fraction of Zr[3](Al,
Ag)[2] phase. The shear-type fracture mode along the maximum shear
plane remains unchanged. The effectiveness of the Zr[3](Al, Ag)[2]
phase for the increase in sigma[f] is presumably because the size of
the phase is too small to contain dislocations. The success of
syntheizing the high-strength bulk amorphous alloy consisting of
nanoscale Zr[3](Al, Ag)[2] phase embedded in an amorphous matrix is
encouraging for future development of bulk amorphous alloys as a
high-strength material.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:zirconium-based bulk amorphous alloy, bulk nanocrystalline alloy,
nanocrystallization, compound dispersed structure, glass transition
******************************************************************************
[ID ]:KL97-222
[AUTH]:Inoue Akihisa, Zhang Tao and Takeuchi Akira
[TITL]:Bulk Amorphous Alloys with High Mechanical Strength and Good Soft
Magnetic Properties in Fe-TM-B (TM=IV-VIII Group Transition Metal)
System
[SOUR]:Appl. Phys. Lett., 71[4] (1997), 464-466
[LAB ]:(3); Inoue
[ABST]:New bulk amorphous alloys exhibiting a wide supercooled liquid region
before crystallization were found Fe-(Co, Ni)-(Zr, Nb, Ta)-(Mo, W)-B
systems. The T[g] is as high as about 870K and the supercooled liquid
region reaches 88K. The high thermal stability of the supercooled
liquid enabled the production of bulk amorphous alloys with diameters
up to 6mm. These bulk amorphous alloys exhibit a high compressive
strength of 3800MPa, high Vickers hardness of 1360, and high corrosion
resistance. Besides, the amorphous alloys exhibit a high magnetic-flux
density of 0.74-0.96T, low coercivity of 1.1-3.2A/m, high permeability
exceeding 1.2 times 10]4[ at 1kHz, and low magnetostriction of about 12
times 10]-6[.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:bulk amorphous alloy, high mechanical strength, good soft magnetic
properties, wide supercooled liquid region
******************************************************************************
[ID ]:KL97-223
[AUTH]:Inoue Akihisa, Zhang Tao and Takeuchi Akira
[TITL]:Micro-Formability of Bulk Amorphous Alloys
[SOUR]:Proc. Int. Conf. Exhib., "Micro Materials '97", Berlin, (1997), 103-108
[LAB ]:(3); Inoue
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:supercooled liquid, bulk amorphous alloy, ideal superplastic
deformability, large glass-forming ability, good micro-formability
******************************************************************************
[ID ]:KL97-224
[AUTH]:Inoue Akihisa, Zhang Tao, Itoi Takaomi and Takeuchi Akira
[TITL]:New Fe-Co-Ni-Zr-B Amorphous Alloys with Wide Supercooled Liquid Regions
and Good Soft Magnetic Properties
[SOUR]:Mater. Trans., JIM, 38[4] (1997), 359-362
[LAB ]:(3); Inoue
[ABST]:New Fe-based amorphous alloys in Fe-Co-Ni-Zr-B system exhibiting a wide
supercooled liquid region before crystallization and good soft magnetic
properties were found to the formed by melt spinning. The composition
range of the amorphous (Fe[1-x-y]Co[x]Ni[y])[70]Zr[10]B[20] alloys with
the wide supercooled liquid region above 50K extends from 0 to 36at%Co
and 0 to 30%Ni and the largest value of the supercooled liquid region
defined by the difference between the glass transition temperature
(T[g]) and crystallization temperature (T[x]), Delta T[x](=T[x]-T[g])
is 68K for Fe[56]Co[7]Ni[7]Zr[10]B[20]. The crystallization from the
supercooled liquid of the Fe[56]Co[7]Ni[7]Zr[10]B[20] alloy upon
continuous heating occurs through a single stage and the resulting
crystallized structure consists of alpha-Fe, Fe[2]Zr and Fe[3]B phases
containing Co and Ni elements. These Fe-based amorphous alloys exhibit
good soft magnetic properties and the saturation magnetization,
coercive force, permeability at 1kHz and Curie temperature are
respectively 0.96T, 2.41A/m, 17700 and 567K for the amorphous
Fe[56]Co[7]Ni[7]Zr[10]B[20] alloy annealed for 600s at 750K. The
finding of the Fe-based amorphous alloys with good soft magnetic
properties and high thermal stability of the supercooled liquid is
important for future development of ferromagnetic bulk amorphous
alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:iron-based amorphous alloy, iron-zirconium-boron system, glass
transition, wide supercooled liquid region, soft magnetic properties
******************************************************************************
[ID ]:KL97-225
[AUTH]:Itoh Naotsugu, Xu W.
[TITL]:Solubility of Hydrogen in Amorphous Pd[1-x]Si[x] Alloys as Hydrogen
Permeable Membranes
[SOUR]:J. Membrane Sci., 126 (1997), 41-51
[LAB ]:(1); National Inst. of Mater. Chem. Res.; LDRAM; Masumoto
[ABST]:Hydrogen solubility of amorphous Pd[1-x]Si[x](x=0.15, 0.175, 0.2)
alloys in the form of ribbon, which were prepared with a single-roller
melt spinning technique, was measured by a pressure-variable method at
elevated temperatures up to 200Ž. It was found that the hydrogen
solubility in the amorphous alloys, strongly depending on the Si
content, decreased with an increase in the Si content, and never obeyed
the Sieverts law. The amorphous alloys showed 3-4 times higher hydrogen
solubility than the corresponding crystallized ones. Based on the
theory proposed by Kirchheim et al., an attempt was made to postulate a
simplified equation to describe the relation between the pressure and
composition of hydrogen in the amorphous alloys. As a result, similar
to the half power law for the crystalline metal, the so-called nth
power law with respect to pressure was found to be applicable for the
amorphous Pd[1-x]Si[x] alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:palladium base alloy, hydrogen permeable, hydrogen solubility,
amorphous
******************************************************************************
[ID ]:KL97-226
[AUTH]:Kanomata Takeshi, Sato Yuka, Sugawara Yasuhiro, Aburatani Shigeyuki,
Kimura Hisa Michi, Kaneko Takejiro, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Heat Capacity of Pd-Si, Ni-Si-B and Zr-Based Metallic Glasses
[SOUR]:Sci. Rep. RITU, A43[2] (1997), 89-95
[LAB ]:(2); Dept. of Appl. Phys., Faculty of Eng., Tohoku Gakuin Univ.; LDRAM;
Inoue; Masumoto
[ABST]:The specific heat of metallic glasses containing Si and B
(Ni[78]Si[10]B[12] and Pd[80]Si[20]) and Zr-based metallic glasses
(Zr[60]Al[15]Cu[15]Ni[7.5]Co[2.5], Zr[65]Al[17.5]Cu[7.5] and
Zr[67]Cu[33]) was measured in the temperature range 77-800 K using an
a.c. calorimeter. Several exothermic and endothermic processes were
observed correspondingly to the transformation sequences for complete
crystallization of all the glasses. The structural relaxation process
appears with a decrease in heat capacity. For Ni-Si-B and Pd-Si glasses
an abrupt increase in the specific heat is observed at the glass
transition temperature T[g]. For Zr-based glasses, however, a
monotonous increase in the specific heat is observed just below T[g].
Then the specific heat makes a peak and decrease abruptly with
increasing temperature. The height of peak increases with heating rate.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:metallic glass, specific heat, glass transition, Zr-based metallic
glass
******************************************************************************
[ID ]:KL97-227
[AUTH]:Kato Hidemi, Kawamura Yoshihito, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Bulk Glassy Zr-Based Alloys Prepared by Consolidation of Glassy Alloy
Powders in Supercooled Liquid Region
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 458-462
[LAB ]:(3); Inoue; Res. Inst. for Electric and Magn. Mater.
[ABST]:We report the effects of extrusion conditions such as the powder
handling processing, extrusion ratio and extrusion temperature on the
tensile strength of glassy alloy compacts consolidated by warm
extrusion in a supercooled liquid state. The alloy used was a
Zr[65]Al[10]Ni[10]Cu[15] (at.%) glassy alloy which has a significant
supercooled liquid region of 105K. The glassy powder compacts were
produced through the extrusion in the supercooled liquid state at
extrusion ratios above four by means of ordinary powder metallurgy
processing and exhibit nearly the same tensile strength as that for the
melt-spun glassy ribbons and the as-cast glassy bulks. The closed
processing, in which the powder was handled in a well-controlled
atmosphere without being exposed to air, moreover, led to a higher
level of strength due to improvement in the powder particle bonding
state as compared with ordinary processing and the tensile strength at
extrusion ratios above three reached 1520MPa.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:glassy alloy, powder metallurgy, warm extrusion, closed processing,
tensile strength
******************************************************************************
[ID ]:KL97-228
[AUTH]:Kawamura Yoshihito, Kato Hidemi, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Fabrication of Bulk Amorphous Alloys by Powder Consolidation
[SOUR]:Int. J. Powder Metall., 33[2] (1997), 50-61
[LAB ]:(1); Inoue; Masaumoto
[ABST]:The first successful synthesis of glassy alloy compacts with full
strength by warm extrusion of atomized glassy powder in the supercooled
liquid state is reported. The effects of powder processing and the
extrusion conditions on the mechanical properties of the compacts were
investigated for amorphous Zr[65]Al[10]Ni[10]Cu[15] with a wide
supercooled liquid region of 105K. The tensile strength and Young's
modulus of the amorphous powder compacts were 1520MPa and 80GPa,
respectively, which are similar to valves obtained in the as-cast bulk
alloy and melt-spun ribbon. The high tensile strength is attributed to
full densification, perfect bonding between powder particles and
retention of ductility by extrusion at extrusion ratios above 4 in the
supercooled liquid state. Powder processing, improved particle bonding,
resulting in high strength at smaller extrusion ratios. The results of
this study have major implications regarding the future development of
bulk amorphous and nanocrystalline materials with complex shapes and
novel properties.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:ZrAlNiCu, amorphous Alloy powder, extrusion, consolidation, mechanical
property
******************************************************************************
[ID ]:KL97-229
[AUTH]:Kawamura Yoshihito, Shibata Tsutomu and Inoue Akihisa
[TITL]:Deformation Behavior and Workability of Supercooled Liquid in
Zr[65]Al[10]Ni[10]Cu[15] Metallic Glass
[SOUR]:Sci. Rep. RITU, A43[2] (1997), 107-113
[LAB ]:(1); Inoue
[ABST]:The tensile deformation behavior and the workability of
Zr[65]Al[10]Ni[10]Cu[15] Metallic Glass with a wide supercooled liquid
have been examined. The glassy solid exhibited the homogeneous
deformation at higher temperatures and lower strain rates. The
supercooled liquid revealed a homogeneous deformation even at high
strain rates above 0.5s]-1[. The strength in the homogeneous
deformation region was lower at higher temperatures and lower strain
rates. The supercooled liquid exhibited similar deformation behavior to
the other high-strain-rate superplastic materials. Using this
superplastic-like deformation in the supercooled liquid, complex-shaped
glassy component with original strength was produced through an
extrusion process.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Zr[65]Al[10]Ni[10]Cu[15], amorphous, supercooled liquid, mechanical
property, superplasticity
******************************************************************************
[ID ]:KL97-230
[AUTH]:Kawamura Yoshihito, Shibata Tsutomu, Inoue Akihisa and Masumoto
Tsuyoshi
[TITL]:Stress Overshoot in Stress-Strain Curves of Zr[65]Al[10]Ni[10]Cu[15]
Metallic Glass
[SOUR]:Appl. Phys. Lett., 71[6] (1997), 779-781
[LAB ]:(1); Inoue; Res. Inst. for Electric and Magn. Mater.
[ABST]:The essential features of the stress overshoot in the stress-strain
curves of Zr[65]Al[10]Ni[10]Cu[15] (at.%) metallic glass that has a
wide supercooled liquid region were revealed. The stress overshoot was
dependent on temperature, strain rate, and stress relaxation. During
the stretch, a change in strain rate gave rise to stress overshoot or
undershoot which was sensitive to the variable quantities in the strain
rate.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Zr[65]Al[10]Ni[10]Cu[15], amorphous alloy, metallic glass, mechanical
property, stress-strain curve
******************************************************************************
[ID ]:KL97-231
[AUTH]:Kawamura Yoshihito, Shibata Tsutomu, Inoue Akihisa and Masumoto
Tsuyoshi
[TITL]:Superplastic Deformation of Zr[65]Al[10]Ni[10]Cu[15] Metallic Glass
[SOUR]:Scr. Mater., 37[4] (1997), 431-436
[LAB ]:(1); Inoue; Res. Inst. for Electric and Magn. Mater.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Zr[65]Al[10]Ni[10]Cu[15], amorphous alloy, metallic glass,
superplasticity, deformation
******************************************************************************
[ID ]:KL97-232
[AUTH]:Kawashima Asahi, Akiyama Eiji, Habazaki Hiroki and Hashimoto Koji
[TITL]:Characterization of Sputter-Deposited Ni-Mo and Ni-W Alloy
Electrocatalysts for Hydrogen Evolution in Alkaline Solution
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 905-909
[LAB ]:(3); Hashimoto
[ABST]:Binary Ni-Mo and Ni-W alloy coatings with good adhesion to nickel
substrate are successfully prepared by d.c. magnetron sputter
deposition method. These alloy electrodes are found to be active
hydrogen evolution electrocatalysts in 1 M NaOH solution at 30Ž. Ni-Mo
alloy electrodes exhibit the highest activity, which is higher than
that of smooth platinum electrode. Leaching treatment in hot
concentrated caustic solution for Ni-Mo alloys significantly enhances
the activity.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Ni-Mo, Ni-W, sputter-deposition, hydrogen evolution, electrocatalyst
******************************************************************************
[ID ]:KL97-233
[AUTH]:Kimura Hisa Michi, Inoue Akihisa, Nishiyama Nobuyuki, Sasamori
Kenichiro, Haruyama Osami and Masumoto Tsuyoshi
[TITL]:Thermal, Mechanical and Physical Properties of Supercooled Liquid in
Pd-Cu-Ni-P Amorphous Alloy
[SOUR]:Sci. Rep. RITU, A43[2] (1997), 101-106
[LAB ]:(2); LDRAM; Inoue; Graduate School, Tohoku Univ; Dept. of Phys., Sci.
Univ. of Tokyo; Gijutsu; Masumoto
[ABST]:The thermal stability, storage modulus (E'), loss tangent (tan delta),
temperature coefficient of thermal expansion (alpha) and electrical
resistivity of a super cooled liquid were measured for an amorphous
Pd[40]Cu[30]Ni[10]P[20] alloy with a wide super cooled liquid region
before crystallization. The wide supercooled liquid region of 80K is
retained even at the low heating rate of 0.083K/s. The E' of the super
cooled liquid decreases monotonously from 6.0 to 0.35GPa with
increasing temperature from 540 to 590K and the tan delta increases
form 0.07 to 0.52. These changes takes place through a single stage.
The alpha value of the supercooled liquid is measured to be 2.0 times
10]-2[ K]-1[ which is larger by three orders than that (2.0 times
10]-5[ K]-1[) for the corresponding amorphous solid. The electrical
resistivity decreases through two stages in the range from 2.27 to
2.15mu Omega m in the super cooled liquid from 563 to 648K. These
physical and mechanical properties of the super cooled liquid are
significantly different from those for the corresponding amorphous
solid and important for future development of basic science of super
cooled liquid and bulk amorphous alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:palladium-copper-phosphorus base amorphous alloy, supercooled liquid,
glass transition, storage modulus, thermal dilatation
******************************************************************************
[ID ]:KL97-234
[AUTH]:Kimura Hisa Michi, Sasamori Kenichiro, Negishi Tadahiro and Inoue
Akihisa
[TITL]:Formation of Nanogranular Amorphous Phase in Rapidly Solidified
Al-Ti-M(M=V, Fe, Co or Ni) Alloys and Their Mechanical Strength
[SOUR]:Nanostruct. Mater., 8[7] (1997), 833-844
[LAB ]:(2); LDRAM; Inoue; Gijutsu
[ABST]:A nanogranular mixed structure consisting of amorphous and fcc-Al
phases was formed in melt-spun Al-Ti-M(M=V, Fe, Co or Ni) alloys
containing more than 92at% Al. The composition range of the
nanogranular structure is the widest for M=Fe and Co, followed by Ni
and then V. The highest Al concentration for formation of the
nanogranular amorphous phase reaches 94% Al for the Fe- and Co
containing alloys. The amorphous and Al phases are homogeneously
coexistent. The grain sizes of the amorphous and Al phases are about 11
and 10nm, respectively, for Al[93]Ti[4]Fe[3] and increase in the order
of Fe[Co[Ni[V. However, their grain sizes keep small values of 8 and
25nm, respectively, even for Al[93]Ti[4]V[3]. These nanogranular alloys
exhibit high tensile strength (sigma[f]) exceeding 1000MPa and high
Vickers hardness (H[v]) above 290 and the highest sigma[f] and H[v] are
450, respectively, for the Al[93]Ti[4]Fe[3] alloy. The sigma[f] and
H[v] change in the order of Fe]Ni]Co]V. This order does not completely
agree with that for the grain sizes of the amorphous and Al phases
because of the difference in their volume fractions. The high
mechanical strength of the nanogranular alloys is due to the refinement
effect of the amorphous and Al grains and t he disordering-induced
strengthening effect of the amorphous phase. The high formation
tendency of the amorphous phase is presumably due to the increase in
the stability of the supercooled liquid against crystallization caused
by the difficulty of atomic diffusivity resulting from the strong
attractive interaction among the constituent elements. The synthesis of
the nanogranular amorphous and Al phases with high mechanical strength
in the Al-rich alloys is important for future development of a new type
of high specific strength material.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:aluminium based alloy, nanogranular amorphous phase, rapidly solidied,
mechanical strength, nanogranular alloy
******************************************************************************
[ID ]:KL97-235
[AUTH]:Kita Kazuhiko, Saitoh Kohji, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Mechanical Properties of Al Based Alloys Containing Quasi-Crystalline
Phase as a Main Component
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 1004-1007
[LAB ]:(2); YKK; Inoue; Masumoto
[ABST]:The application of high-pressure Ar atomization to Al-Mn-TM and
Al-Cr-TM(TM=Co, Ni) ternary alloys caused the formation of a coexistent
Al+quasi-crystalline (Q) structure where the Q phase is included as a
main constituent phase. Subsequently, a bulk alloy consisting of Q and
Al was produced by extrusion of the atomized powder. The particle size
and inter-particle spacing of the Q particles are 150 and 140nm,
respectively and the volume fraction is about 60%. The mixed phase
alloy exhibit high tensile strength and elongation of 720MPa and 6.4%,
respectively for Al[93]Mn[5]Co[2] alloy. The Young's modulus is also as
high as 92GPa. The Al-based alloy exhibits a small coefficient of
thermal expansion of 20 times 10]-6[ K]-1[ between 373-473K which is
about 20% smaller than those for conventional Al alloys. These superior
mechanical properties are presumably due to the fine dispersion and
high volume fraction of Q particles and the high rigidness of the Q
phase.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:high-pressure atomization, extrusion, atomized power, Q-phase
******************************************************************************
[ID ]:KL97-236
[AUTH]:Li Xiang Yang, Akiyama Eiji, Habazaki Hiroki, Kawashima Asahi, Asami
Katsuhiko and Hashimoto Koji
[TITL]:An XPS Study of Passive Films on Corrosion-Resistant Cr-Zr Alloys
Prepared by Sputter Deposition
[SOUR]:Corros. Sci., 39[8] (1997), 1365-1380
[LAB ]:(2); Hashimoto; LDRAM
[ABST]:X-ray photo-electron spectroscopy (XPS) has been used to examine
spontaneously passivated films formed on sputter-deposited Cr-Zr alloys
in 6 M HCl solution open to air at 30Ž, for a better understanding of
the high corrosion resistance of these alloys. The open circuit
potentials of the Cr-Zr alloys are located in the passive regions of
both chromium and zirconium, and all of the Cr-Zr alloys examined are
spontaneously passivated. An increase in chromium content of the alloys
enhances the cathodic activity for oxygen reduction and content of the
alloys enhances the cathodic activity for oxygen reduction and
decreases the anodic current density with a consequent ennoblement of
the open circuit potential. XPS analysis indicates that the air-formed
films on these alloys are composed of homogeneous double oxyhydroxide
consisting of both chromium and zirconium ions. The cationic
composition of the film is almost the same as the alloy composition
although slight enrichment of zirconium occurs. The air-formed film is
protective enough to lead to spontaneous passivation of these alloys.
The immersion for a long period of time results in a slight deficiency
in zirconium in the exterior of the passive film as a result of gradual
dissolution of zirconium. At the same time, the total amount of
chromium in the passive film increases. The passive film consists of
double oxyhydroxide of chromium and zirconium, in which the cationic
composition is almost the same as the alloy composition. The formation
of the passive film consisting of double oxyhydroxide of chromium and
zirconium is responsible for the higher corrosion resistance of these
Cr-Zr alloys in comparison with chromium and zirconium metal.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:alloy, sputtered film, polarization, XPS, passive film
******************************************************************************
[ID ]:KL97-237
[AUTH]:Li Xiang Yang, Akiyama Eiji, Habazaki Hiroki, Kawashima Asahi, Asami
Katsuhiko and Hashimoto Koji
[TITL]:Spontaneously Passivated Films on Sputter-Deposited Cr-Ti Alloys in 6M
HCl Solution
[SOUR]:Corros. Sci., 39[5] (1997), 935-948
[LAB ]:(2); Hashimoto; LDRAM
[ABST]:Among sputter-deposited Cr-Ti alloys, 30-65at% Ti alloys are
amorphized. The Cr-Ti alloys with 22at% or less Ti are bcc single phase
alloys. Regardless of the crystallinity, the open circuit potentials of
sputter-deposited Cr-Ti alloys are located in the passive regions of
both titanium and chromium in 6 M HCl solution open to air at 30Ž, and
all-Cr-Ti alloys are spontaneously passivated. X-ray photo-electron
spectroscopy (XPS) analysis reveals that the spontaneously formed
passive film as well as air-formed film is slightly rich in titanium
ions mainly because of preferential oxidation of titanium. According to
angle-resolved XPS measurement, no concentration gradient of Cr]3+[ and
Ti]4+[ ions has been detected in depth of the passive film. Analysis of
binding energies of core electrons of Cr]3+[ and Ti]4+[ cations shows
that Cr]3+[ and Ti]4+[ cations are located very closely in the film so
as to show the electronic interaction, and the film is not composed of
a heterogeneous mixture of chromium and titanium oxyhydroxides but of
homogeneous double oxyhydroxide consisting of Cr]3+[ and Ti]4+[
cations. The formation of the homogeneous double oxyhydroxide film
containing both Cr]3+[ and Ti]4+[ cations is responsible for extremely
higher corrosion resistance of the homogeneous single phase Cr-Ti
alloys in 6 M HCl open to air at 30Ž in comparison with the corrosion
resistance of chromium and titanium metals.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:alloy, sputtered film, polarization, XPS, passive film
******************************************************************************
[ID ]:KL97-238
[AUTH]:Louzguine Dmitri Valentinovich and Inoue Akihisa
[TITL]:Multicomponent Si-Based Amorphous Alloys Produced by Melt Spinning and
Their Crystallization Behaviour
[SOUR]:Mater. Trans., JIM, 38[12] (1997), 1095-1099
[LAB ]:(2); Inoue
[ABST]:By the addition of some definite transition metals Ni, Cr and Zr to the
Si-Al-Fe system, the maximum Si content for formation of an amorphous
single phase was extended to 50 and 55at%Si. The Si-based amorphous
alloys are characterized by high values of electrical resistivity
(11.7-12.3mu Omega m) and hardness (sim 930HV). Their crystallization
temperatures exceed 700K, which is higher by about 100K than those for
Si[45]Al-Fe-Cr and Si[45]Al-Fe-Ni quaternary alloys. During heat
treatment of an amorphous Si[55]Al[20]Fe[10]Ni[5]Cr[5]Zr[5] alloy at
the temperature above the crystallization temperature, a 6-component
Si[10]Al[4]Fe[2]NiCrZr phase with a tetragonal structure having lattice
parameters a=0.6890nm and c=0.9402nm is formed as a main constituent
phase. The difficulty of the precipitation of the multicomponent
crystalline phase with the large volume of unit cell during rapid
solidification is presumed to be the main reason for the formation of
the Si-based amorphous phase.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:silicon-based amorphous alloy, rapidly solidified phase, intermetallic
compound, crystallization behaviour, multicomponent phase
******************************************************************************
[ID ]:KL97-239
[AUTH]:Louzguine Domitri Valentinovich, Takeuchi Akira and Inoue Akihisa
[TITL]:New Amorphous Alloys in Al-Si-Fe-Ni and Al-Si-Fe-Co Systems and Their
Crystallization Behaviour
[SOUR]:Mater. Trans., JIM, 38[7] (1997), 595-598
[LAB ]:(3); Inoue
[ABST]:An amorphous single phase was formed in wide composition ranges of
rapidly solidified Al-Si-Fe-Ni and Al-Si-Fe-Co alloys. In comparison
with Al-Si-Fe system, the composition range of the amorphous alloys is
the widest in the Al-Si-Fe-Ni system and becomes narrower in the
Al-Si-Fe-Co system in the direction of Fe concentration axis. The
extension of the compositional range in the direction of the Si
concentration axis leads to the formation of new amorphous alloys with
high silicon concentrations: Si[45]Al[31]Fe[20]Ni[4],
Si[45]Al[36]Fe[15]Ni[4] and Si[45]Al[41]Fe[10]Co[4]. The crystallized
structure consists of fcc Al, cubic Si and some ternary compounds of
AlFeSi, AlSiNi, AlFeNi and AlSi Co depending on their alloy
compositions.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:aluminium amorphous alloy, composition, intermetallic compound, rapidly
solidified phase, crystallization behaviour
******************************************************************************
[ID ]:KL97-240
[AUTH]:Miura Susumu, Matsuzaki Kunio, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Formation of Metastable Phases in the Zr-Al System by Electron Beam
Deposition
[SOUR]:Jpn. J. Appl. Phys., 36[2A] (1997), L130-L132
[LAB ]:(2); Graduate Student, Tohoku Univ.; Inoue; The Res. Inst. of Electric
and Magnetic Alloys;
[ABST]:Zr-Al binary alloy films with a thickness of about 2mu m prepared by
electron beam deposition were found to exist in an amorphous phase in
the composition range of 15 to 60at% Al, although no amorphous phase
has been reported in rapidly solidified Zr-Al alloys. The deviation of
the Al content from the range causes the formation of mixed
hcp-Zr+metastable bcc-Zr phases in the range of 5 to 15 Al at% and
L1[2]-type Al[3]Zr phases in the range of 60 to 85at% Al. The hardness
of the amorphous Zr-Al films increases from 5.98 to 9.18GPa as the Al
content increases from 20 to 58at%.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:amorphous, metastable, film, electron beam deposition, hardness
******************************************************************************
[ID ]:KL97-241
[AUTH]:Mizushima Takao, Makino Akihiro and Inoue Akihisa
[TITL]:Effect of Fe Content on the Glass-Forming Ability, Thermal Stability of
Supercooled Liquid and Magnetic Properties of
Fe[93-x]Al[5]Ga[2](P[0.55]C[0.25]B[0.2])[x] Amorphous Alloys
[SOUR]:Sci. Rep. RITU, A43[2] (1997), 123-128
[LAB ]:(2); Central Res. Lab., Alps Electric Co. Ltd.; Inoue
[ABST]:The compositional dependence of thermal stability, glass-forming
ability and magnetic properties was examined for the
Fe[93-x]Al[5]Ga[2](P[0.55]C[0.25]B[0.2])[x] alloys. As the Fe content
decreases from 75 to 70at%, the supercooled liquid region Delta
T[x](=Tx-Tg) and the maximum sample thickness for glass formation
(t[max]) increase from 38 to 70K and 115 to 180mu m, respectively. The
increase in Delta T[x] is due to a more significant increase in
crystallization temperature (T[x]) which exceeds the degree of the
increase in glass transition temperature (T[g]). The increases in the
thermal stability of the supercooled liquid and the glass-forming
ability are presumably because the optimum metalloid content increases
to about 23 at% by the dissolution of Al and Ga elements with larger
atomic sizes. Furthermore, the increase in the metalloid content to 23
at% was found to cause the improvement of soft magnetic properties
through the decrease in coercivity to 4A/m and the increase in
permeability at 1kHz to 2 times 10]4[, though the saturation
magnetization decreases to 120 times 10]-6[Wbm/kg. The improvement is
interpreted to result from the achievement of the low saturated
magnetostriction (sigma[s]) of 10 times 10]-6[. The finding of the new
Fe-based amorphous alloys with the wide supercooled liquid region
before crystallization, the large glass-forming ability and the good
soft magnetic properties combined with the low lambda[s] is important
for the future development of ferromagnetic bulk amorphous alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:ferromagnetic glassy alloy, rapid solidification, wide supercooled
liquid region, soft-magnetic property, sample thickness
******************************************************************************
[ID ]:KL97-242
[AUTH]:Mizushima Takao, Makino Akihiro and Inoue Akihisa
[TITL]:Structure and Magnetic Properties of Fe-Based Glassy Alloys
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 721-725
[LAB ]:(2); Alps Electric Co., Ltd.; Inoue
[ABST]:A multicomponent Fe[73]Al[5]Ga[2]P[11]C[5]B[4] alloy has a wide
supercooled liquid region before crystallization and ferromagnetism at
room temperature. Structure and magnetic properties of melt-spun
Fe[73]Al[5]Ga[2]P[11]C[5]B[4] alloys with t he thickness from 15 to
230mu m were investigated. The critical thickness for Fe based glassy
alloy to maintain single amorphous phase is about 135mu m. Saturation
magnetization (sigma[s]), coercive force (H[c]) and effective
permeability (mu[e]) at 1kHz indicate constant value, 1.8 times
10]-4[Wbm kg]-1[, 3A m]-1[ and 8000 respectively, with the sample
thickness of 135mu m. The magnetic properties of Fe based glassy alloy
annealed at 773K for 600s are compared with that of Fe[78]Si[9]B[13]
amorphous alloy. It is expected that the Fe based glassy alloy will be
amorphous bulk material which has good soft magnetic properties.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:ferromagnetic glassy alloy, rapid solidification, wide supercooled
liquid region, soft magnetic property, sample thickness
******************************************************************************
[ID ]:KL97-243
[AUTH]:Mizushima Takao, Makino Akihiro and Inoue Akihisa
[TITL]:Thermal Stability and Magnetic Properties of Fe-Al-Ga-P-C-B-Si
Amorphous Thick Sheets
[SOUR]:IEEE Trans. Magn., 33[5] (1997), 3784-3786
[LAB ]:(2); Alps Electric Co., Ltd.; Inoue
[ABST]:The structure and magnetic properties of melt-spun multicomponent
Fe[72]Ga[2]Al[5]P[11-x]C[6]B[4]Si[x](x=0-10) alloy sheets were
investigated. The increases in the thermal stability and glass forming
ability, and the improvement of the soft magnetic properties were
recognized with the replacement of P by 1-2at%Si. The supercooled
liquid region (Delta T[x]) defined by the difference between
crystallization temperature (T[x]) and glass transition temperature
(T[g]) increases from 51K for the Fe[72]Al[5]Ga[2]P[11]C[6]B[4] alloy
to 65K for the Fe[72]Al[5]Ga[2]P[9]C[6]B[4]Si[2] alloy, and then
decreases with increasing Si content. The maximum thickness for glass
formation (t[max]) also increases from 140mu m for the
Fe[72]Al[5]Ga[2]P[11]C[6]B[4] alloy to 190mu m for the
Fe[72]Al[5]Ga[2]P[9]C[6]B[4]Si[2] alloy. The increases in Delta T[x]
and t[max] are presumably because of increased agreement with three
empirical rules for glass formation. The soft magnetic properties at
the thickness of over 70mu m are also improved by the replacement of
1-2at%Si. The magnetic properties for the
Fe[72]Al[5]Ga[2]P[9]C[6]B[4]Si[2] amorphous alloy with the thickness of
190mu m after optimum annealing (623K times 1.8ks) are 169 times 10]-6[
Wbmkg]-1[ for saturation magnetization (sigma[s]), 1.0A/m for coercive
force (H[c]), and 9000 for permeability (mu[e]) at 1kHz. It is
therefore expected that the Fe-based amorphous alloy containing 2at%Si
is widely used as a bulk amorphous material with good soft magnetic
properties.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Fe-based amorphous alloy, thick sheet, thermal stability, soft magnetic
property, glass-forming ability
******************************************************************************
[ID ]:KL97-244
[AUTH]:Myung Wha Nam, Park Kyoung Hee, Jang Dal Hwan, Battezzati L.
[TITL]:Characterization of the Non-Isothermal Viscous Flow and Thermal
Stability of Amorphous Zr-Al-Ni-Cu Alloys with a Wide Supercooled
Liquid Region
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 406-409
[LAB ]:(2); Chonnam National Univ.; Chimica Fisica e Chimica dei Materiali.,
Univ. di Torino, Italy; Inoue; Res. Inst. for Electric and Magn. Mater.
[ABST]:The thermal stability and viscous flow behavior of amorphous
Zr[65]Al[8]Ni[27-x]Cu[x](x=12, 17 and 22) ribbons were examined by
using differential scanning calorimetry and thermomechanical analysis.
It was observed that the viscosity decreases with increasing
temperature until the first steady-state viscous flow temperature is
reached and above this temperature the viscosity depends on both the
composition and applied stress.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:free volume, viscosity, viscous flow, thermal stability
******************************************************************************
[ID ]:KL97-245
[AUTH]:Nishiyama Nobuyuki and Inoue Akihisa
[TITL]:Flux Treated Pd-Cu-Ni-P Amorphous Alloy Having Low Critical Cooling
Rate
[SOUR]:Mater. Trans., JIM, 38[5] (1997), 464-472
[LAB ]:(2); Graduate Student, Tohoku Univ.; Inoue
[ABST]:A Pd[40]Cu[30]Ni[10]P[20] alloy subjected to B[2]O[3] flux treatment
was found to have a low critical cooling rate (R[c]) of 0.100K/s for
glass formation and a large sample thickness (t[max]) of 72mm by the
water quenching process. The R[c] and t[max] exceed largely those
(R[c]=1.57K/s, t[max]=40mm) for the Pd-Cu-Ni-P alloy without the flux
treatment. It is concluded that the flux treatment causes a significant
increase in the thermal stability of the supercooled liquid. The glass
transition temperature (T[g]) remains unchanged in the fluxed state,
but the crystallization temperature (T[x]) increases by 7K, leading to
the extension of the supercooled liquid region defined by Delta
T[x](=T[x]-T[g]) to 98K which is larger than that (91K) for the
non-fluxed sample. The decrease in R[c] and the increases in t[max] and
Delta T[x] for the fluxed sample are presumably due to the suppression
of heterogeneous nucleation for crystallization resulting from the
increase in the degree of cleanness of the molten alloy. Besides, the
Pd-Cu-Ni-P amorphous alloy has lower R[c] and melting temperature
(T[m]) and larger t[max], Delta T[x] and T[g]/T[m] values, as compared
with those for Pd[40]Ni[40]P[20] alloy. The larger glass-forming
ability for the Pd-Cu-Ni-P alloy is presumably due to the increase in
the degree of the satisfaction of the three empirical rules for the
achievement of larger glass-forming ability resulting from the more
systematic change in atomic size in the order Pd gg Cu]Ni gg P and the
generation of Cu-Pd and Cu-P atomic pairs with negative heats of
mixing. There is no appreciable difference in the T[g], T[x] and
crystallization behavior between the cast 72mm]phi[ amorphous ingot and
melt-spun amorphous ribbon. The finding of the fluxed
Pd[40]Cu[30]Ni[10]P[20] alloy with the lower R[c] and larger t[max]
values is promising for the future development of bulk amorphous
alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:bulk amorphous alloy, B[2]O[3] flux treatment, wide supercooled liquid
region, low critical cooling rate, continuous-cooling-transformation
curve
******************************************************************************
[ID ]:KL97-246
[AUTH]:Omata Shigeo, Tanaka Yasuhiko, Ishida Toshiyuki, Sato Akikazu and Inoue
Akihisa
[TITL]:Nucleation-and-Growth Kinetics of Small Crystals in Amorphous
Al[88]Ce[2]Ni[9]Fe
[SOUR]:Philos. Mag. A, 76[2] (1997), 387-412
[LAB ]:(2); Dept. of Mater. Sci. and Eng., Tokyo Inst. of Technol.; Inoue
[ABST]:An amorphous Al[88]Ce[2]Ni[9]Fe alloy has been prepared to contain
dispersed small Al crystals by a single-roller melt-spinning technique.
The growth kinetics of the Al crystals embedded in amorphous phase have
been examined by measuring their growth rates. It is found that the
crystal size increases to saturation at different rates and to
different sizes depending on the ageing temperature. A surface effect
is also noted upon ageing thin-foil specimens prepared for electron
microscopy. The activation energy for the crystal growth is estimated
to be 0.5-0.7eV. Based on these observations a possible diffusion
mechanism in the amorphous phase is discussed with particular interest
in the atomic structure.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:aluminum amorphous alloy, nanocrystallization, nucleation, growth
kinetics, Al crystal
******************************************************************************
[ID ]:KL97-247
[AUTH]:Park Changyong, Saito Masatoshi, Takeuchi Akira, Inoue Akihisa and
Waseda Yoshio
[TITL]:Structural Study of Amorphous Fe[89]Nd[7]B[4] and Fe[89]Zr[7]B[4]
Alloys by X-ray Diffraction
[SOUR]:High Temp. Mater. Process., 16[1] (1997), 57-64
[LAB ]:(2); Inst. for Adv. Mater. Processing, Tohoku Univ.; Inoue
[ABST]:The local ordering structure of amorphous Fe[89]Nd[7]B[4] and
Fe[89]Zr[7]B[4] alloys has been determined by anomalous X-ray
scattering (AXS) coupled with the conventional X-ray diffraction method
using Mo K[alpha] radiation. The atomic distance and its coordination
number in the nearest neighbor region obtained by a least-squares
variational method indicate that the local ordering structure of both
amorphous alloys appears to be no closer to the crystalline
precipitates than a random packing of the present alloy composition and
then any specific different structural feature could not be suggested
in these two as-quenched amorphous alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Fe-Nd-B, Fe-Zr-B, anomalous, x-ray scattering, local ordering
structure, amorphous
******************************************************************************
[ID ]:KL97-248
[AUTH]:Read H.G
[TITL]:Preliminary Atom Probe Studies of PdNi(Cu)P Supercooled Liquids
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 453-457
[LAB ]:(2); National Res. Inst. for Met.; Inoue
[ABST]:The microstructural development during annealing in the supercooled
liquid region of amorphous Pd[46]Ni[36]P[18], which is supposedly of
phase-separating composition, is compared and contrasted with those of
Pd[48]Ni[32]P[20] and Pd[40]Ni[10]Cu[30]P[20]. High resolution electron
microscopy showed that the as-quenched alloys were fully amorphous
while atom probe field ion microscopy (APFIM) showed random solute
distributions, typical of amorphous materials. Annealing in their
respective supercooled liquid regions did not result in the formation
of compositionally-modulated microstructures prior to the onset of
crystallization.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:amorphous alloy, supercooled liquid, Phase separation, APFIM, HREM
******************************************************************************
[ID ]:KL97-249
[AUTH]:Saito H.
[TITL]:Concentration Dependence of the Magnetic Properties of Melt-Quenched
P-Type Mg[30]Gd[x]Zn[70-x] Quasicrystals
[SOUR]:J. Alloys Compd., 252 (1997), 6-11
[LAB ]:(2); Dept. of Mater. Sci., Faculty of Eng., Tohoku Univ.; Inst. for
Solid State Phys., The Univ. of Tokyo; Inoue
[ABST]:Mg[30]Gd[x]Zn[70-x](x=7, 8, 9 and 10) quasicrystals have been prepared
in order to investigate their crystal structure and magnetic
properties. The quasicrystal structure has been identified as a P-type
with a Frank-Kasper-type structure. The temperature dependence of DC
magnetic susceptibility follows Curie-Weiss law. The Gd-Gd exchange
interaction is predominantly antiferromagnetic for all quasicrystals
since their paramagnetic Curie temperature is negative. The magnitude
of theta[p] increases with the increase in the Gd content and the
saturation of high-field magnetization curves becomes easier with
decreasing Gd content. In these alloys, the spin-glass state appears
and the spin freezing temperature T[f] increases with increasing Gd
content. The value of T[f] for the P-type Mg[30]Gd[8]Zn[62]
quasicrystal is comparable to that for an F-type Mg[42]Gd[8]Zn[50]
quasicrystal.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:quasicrystal, Frank-Kasper, paramagnetic Curie temperature, spin-glass,
localized magnetic moment, RKKY interaction
******************************************************************************
[ID ]:KL97-250
[AUTH]:Shibata Kaoru, Higuchi Takeshi, Tsai An Pang, Imai Masayuki and Suzuki
Kenji
[TITL]:Isothermal Evolution of Long Range Order in Bulk Metallic Glass
Ni[15]Pt[60]P[25] near Glass Transition: In-Situ SANS Measurement
[SOUR]:Prog. Theor. Phys. Suppl., [126] (1997), 75-78
[LAB ]:(2); Suzuki; National Res. Inst. for Met.; Neutron Scattering Lab.
[ABST]:In-situ measurements of small angle neutron scattering from a bulk
metallic glass Ni[15]Pt[60]P[25] were carried out in the momentum
transfer range of 0.008[Q[0.08 angstrom]-1[ as a function of the
holding time during isothermal annealing at the temperature T[a]=483K
just below the glass transition temperature T[g]=488K. The small angle
neutron scattering intensities initially increase with holding time and
reach saturation values. The small angle neutron scattering intensity
of the glass cooled down to room temperature after the annealing
increases at the every momentum transfer value observed. The small
angle neutron scattering intensities follow a Q]-4[ dependence and have
no peak structure in the momentum transfer range observed. There is no
evidence for any phase separations in nanometer length scale to occur
in this glass.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:bulk metallic glass Ni[15]Pt[60]P[25], glass transition, in-situ small
angle neutron scattering
******************************************************************************
[ID ]:KL97-251
[AUTH]:Suzuki Kiyonori, Cadogan John Michael, Sahajwalla Veena, Inoue Akihisa
and Masumoto Tsuyoshi
[TITL]:The Role of Alloying Elements in Cu-Free Nanocrystalline Fe-Nb-B Soft
Magnetic Alloys
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 554-558
[LAB ]:(2); The Univ. of New South Wales,; Inoue
[ABST]:In order to clarify the role of alloying elements in Cu-free
nanocrystalline Fe-Nb-B soft magnetic alloys, we have examined the
kinetics of primary crystallization, the microstructure after primary
crystallization, the changes in Curie temperature (T[c]) and the
hyperfine interactions of the amorphous phase upon primary
crystallization in Fe[86-x]Nb[x]B[14](x=0, 2, 4, 5, 6 and 8) alloys.
The mean grain size after primary crystallization decreased drastically
in the x range 4-6 at.%. The kinetic analysis of the primary
crystallization reaction showed that the decrease in the grain size can
be attributed to the commencement of homogeneous nucleation. T[c] of
the amorphous phase increased with the B enrichment during primary
crystallization. T[c] decreased with Nb content and the hyperfine field
distribution of the residual amorphous phase after primary
crystallization for the x=6 sample showed the presence of a
non-magnetic component. These results suggest that Nb plays a role in
the formation of the nanostructure by accelerating nucleation, as does
B in the generation of a strong intergranular magnetic coupling,
through increasing the T[c] of the residual amorphous phase.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Fe-Nb-B, amorphous alloys, nanocrystalline alloys, soft magnetic
properties, crystallization
******************************************************************************
[ID ]:KL97-252
[AUTH]:Takeuchi Akira, Inoue Akihisa and Makino Akihiro
[TITL]:Improvement of Hard Magnetic Properties of Fe[90]Nd[7]B[3] Alloys by
Two-Stage Crystallization Treatment
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 636-640
[LAB ]:(2); Inoue; Alps Co.
[ABST]:The magnetic properties of a partially crystallized Fe[90]Nd[7]B[3]
amorphous alloy were improved by a two-stage crystallization treatment:
(1) the first-stage annealing (923K times 300s) is employed as an
optimal treatment to obtain rather good hard magnetic properties and is
followed by water quenching; (2) the second-stage annealing at 723K for
60-3600s is followed by water quenching. The remanence (B[r]), coercive
field ([i]H[c]) and maximum energy product ((BH)[max]) are 1.00T, 200kA
m]-1[ and 100kJ m]-3[, respectively, at the first-stage, and increase
to 1.16T, 232kA m]-1[ and 135kJ m]-3[, respectively, by the second
annealing stage. The further increase in the hard magnetic properties
is presumably due to the increase in the precipitation amount of
nanoscale b.c.c.-Fe phase with high saturation magnetization (B[s]) and
high Curie temperature (T[c]) in t he retainment of the nanoscale
grains of the former b.c.c.-Fe and Fe[14]Nd[2]B phases. The finding of
the usefulness of the multistage crystallization treatment leading to
the formation of the fully crystallized nanostructure is important
because of the expectation of the further improvement of functional
properties resulting from the nanoscale mixed structure.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:bcc-Fe, Fe[14]Nd[2]B, Fe-Nd-B amorphous alloy, hard magnetic
properties, high Fe concentration
******************************************************************************
[ID ]:KL97-253
[AUTH]:Tsai An Pang, Kamiyama Tomoaki, Kawamura Yoshihito, Inoue Akihisa and
Masumoto Tsuyoshi
[TITL]:Formation and Precipitation Mechanism of Nanoscale Al Particles in
Al-Ni Base Amorphous Alloys
[SOUR]:Acta Mater., 45[4] (1997), 1477-1487
[LAB ]:(2); National Res. Inst. for Met., Tsukuba; Suzuki; Inoue; The Res.
Inst. for Electric and Magnetic Mater.
[ABST]:Nanoscale fcc-Al particles which are homogeneously dispersed within
amorphous phase have been obtained by annealing the amorphous alloys.
Scanning and isothermal calorimetry, together with X-ray diffraction
and high resolution transmission electron microscopy (TEM) have been
employed to study precipitation of nanoscale Al particles in Al-based
amorphous alloys. In the cases of Al[87]Ni[10]Ce[3], Al[87]Ni[10]Zr[3]
and Al[87]Ni[7]Cu[3]Ce[3] alloys, the monotonously decreasing
isothermal calorimetric signal, characteristic of a grain growth
process has been observed in the course of precipitation of nanoscale
Al particles in these amorphous alloys. It is shown that the Al
particles grow by diffusion controlled growth with a small activation
energy in the range of 1.3-1.7eV. TEM of as-quenched Al[87]Ni[10]Ce[3]
revealed an amorphous structure but a significant concentration
fluctuation was observed in the alloy by small-angle X-ray scattering
(SAXS). The concentration fluctuation is presumed to be associated with
pre-existing nuclei. Formation of nanocrystalline fcc-Al through a
grain growth process has been identified in several Al-based amorphous
alloys with lambda in the range of 0.04-0.07 (lambda is a parameter
responsible for the strain of the matrix induced by solute elements)
and with Al content in the range of 82-90 at.%. This study gave
indications in structure-control for gaining a nanoscale fcc-Al
dispersed in an amorphous matrix.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Al-Ni-Ce, Al-Ni-Zr, amorphous alloy, crystallization, TEM
******************************************************************************
[ID ]:KL97-254
[AUTH]:Tsai An Pang, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Phason Strains on Growth, Stability and Structure of Icosahedral Phases
[SOUR]:Prog. Cryst. Growth Charact., 34 (1997), 221-236
[LAB ]:(2); Inoue; Masumoto
[ABST]:Growth, stability and structure of icosahedral (i-) phases have been
studied by electron diffraction and X-ray diffraction in relation with
the phason strains. Three alloy systems; AlPdCr, AlPdMn and AlCuV were
chosen in this study. An i- Al[72]Pd[25]Cr[3] grain has been analysed
to have a phason matrix toward to a tetragonal or orthorhombic
structure. Stability of the i-phases correlated with the phason
relaxation was discussed in Al-Pd-Mn system. A quenched
i-Al[74]Pd[17]Mn[9] close to but containing significant phason strains,
revealed that the phason relaxation induced by precipitation of
crystalline phases upon annealing. Phason disorder dominated by the
chemical composition was evidenced in a composition study in Al-Pd-Mn
system. A high density random phasons characterized the icosahedral
glass phase was observed in AlCuV alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Phason disorder, relaxation, icosahedral glass
******************************************************************************
[ID ]:KL97-255
[AUTH]:Turchanin A.A, Tomilin I.A, Inoue Akihisa and Zubkov A.
[TITL]:Experimental Determination of the Formation Enthalpies of
Zirconium-Nickel-Aluminium Amorphous Alloys
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 487-490
[LAB ]:(2); Moscow Steel and Alloys Inst.; Inoue
[ABST]:A method of solution calorimetry has been applied for thermochemical
study of amorphous alloys in the Zr-Ni-Al system. Heats of dissolution
for five amorphous alloys Zr[0.60]Ni[0.40], Zr[0.60]Ni[0.35]Al[0.05],
Zr[0.60]Ni[0.30]Al[0.10], Zr[0.60]Ni[0.25]Al[0.15] and
Zr[0.60]Ni[0.20]Al[0.20] in liquid Al were measured with the help of
high temperature isoperibol Calvet-type calorimeter. The measured molar
heats of dissolution along with these values for pure nickel and
zirconium determined before allowed to calculate molar enthalpies of
formation for the listed amorphous alloys from the pure constituent
metals in the crystalline state. Enthalpy of formation for the
Zr[0.60]Ni[0.40] amorphous alloy is in good agreement with both our
previous results for the amorphous alloys in the Zr-Ni system and the
available literature data. Enthalpies of formation for the Zr-Ni-Al
amorphous alloys from the pure crystalline metals are strongly negative
that shows considerable negative deviation of these alloys from the
ideal behaviour and points to considerable interaction energy between
atoms of these components in amorphous phase. Partial substitution Ni
by Al in the Zr[0.60]Ni[0.40] amorphous alloy results in an increase of
enthalpy of formation at low concentration of Al followed by a decrease
of this value at higher concentration of Al, i.e. small addition of Al
into Ni-Zr based amorphous alloy decreases and considerable addition of
Al increases bond forces in this phase.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:formation enthalpies, Zr-Ni-Al amorphous alloys
******************************************************************************
[ID ]:KL97-256
[AUTH]:Yokoyama Yoshihiko, Note Ryunosuke, Kimura Shigeo, Inoue Akihisa,
Fukaura Kenzo and Sunada Hisakichi
[TITL]:Preparation of Decagonal Al-Ni-Co Single Quasicrystal by Czochralski
Method
[SOUR]:Mater. Trans., JIM, 38[11] (1997), 943-949
[LAB ]:(2); Himeji Inst. of Technol.; Gijutsu; Inoue
[ABST]:We constructed a partial isothermal phase diagram including a decagonal
(d-) phase in the Al-Ni-Co system and determined the composition of the
liquid in equilibrium with the stoichiometric d-phase. The d-phase is
formed through a peritectic reaction between the B2 phase and the
liquid phase. A seed d-phase prepared by selecting an optimum
composition of the liquid phase was used for growing a large-scale
d-quasicrystal by the Czochralski method. As a result, we have product
a single decagonal quasicrystal with the size of 60mm in length and 1
to 7mm in diameter and the mean composition of
Al[72.2]Ni[12.1]Co[15.7].
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:single decagonal quasicrystal, aluminum-nickel-cobalt alloy system,
phase diagram, isothermal section, Czochralski method
******************************************************************************
[ID ]:KL97-257
[AUTH]:Yokoyama Yoshihiko, Yamada Yoshihiro, Fukaura Kenzo, Sunada Hisakichi,
Inoue Akihisa and Note Ryunosuke
[TITL]:Stable Decagonal Quasicrystal in an Al-Mn-Fe-Ge System
[SOUR]:Jpn. J. Appl. Phys., 36 (1997), 6470-6474
[LAB ]:(2); Himeji Inst. of Technol.; Inoue; Gijutsu
[ABST]:A thermodynamically stable quasicrystalline phase with a decagonal
structure was found to be formed in an Al[40]Mn[25]Fe[15]Ge[20]. The
single phase was prepared by conventional solidification, followed by
annealing for 100h at 1050K and then water quenching. The decagonal
phase was identified to be the 6 layer (1.2nm) Al[4]Mn-type decagonal
structure. This alloy exhibits magnetization of 6.3emu/g in an applied
field of 10kOe at 40K.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:stable quasicrystal, decagonal type, Al-Mn-Fe-Ge, full annealing,
magnetic properties
******************************************************************************
[ID ]:KL97-258
[AUTH]:Yubuta Kunio, Sun Wei and Hiraga Kenji
[TITL]:A New Crystalline Phase Related to Decagonal Quasicrystals with
Non-Central Symmetry in Al-Co-Pd Alloys
[SOUR]:Philos. Mag. A, 75[1] (1997), 273-284
[LAB ]:(3); Hiraga
[ABST]:A new crystalline phase, related to decagonal quasicrystals with
non-central symmetry, is found in conventionally solidified
Al[70]Co[20]Pd[10] and Al[73]Co[22]Pd[5] alloys. The new crystalline
phase, which is called a W-phase hereafter, has an orthorhombic
structure with lattice parameters a=0.82nm, b=2.06nm and c=2.35nm, and
the space group Pmn2[1] (No. 31). From electron diffraction and
high-resolution electron microscopy observations of the W-phase, we
propose a tentative structural model, which is constructed by modifying
the structure of an Al-Ni-Co decagonal quasicrystal. A non-central
symmetric decagonal quasicrystal with 0.4 nm periodicity is found in
rapidly solidified Al[70]Co[20]Pd[10] and Al[73]Co[22]Pd[5] alloys. The
structural relationships between the W-phase and decagonal quasicrystal
are discussed.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:Al-Co-Pd, non-central symmetry, decagonal quasicrystal, crystalline
approximant, high-resolution electron
******************************************************************************
[ID ]:KL97-259
[AUTH]:Zhang Wei, Takeuchi Akira and Inoue Akihisa
[TITL]:Amorphous Nd-Fe-Si Thick Ribbons and Their Hard Magnetic Properties
[SOUR]:Mater. Trans., JIM, 38[11] (1997), 1027-1030
[LAB ]:(3); Inoue
[ABST]:Hard magnetic Nd[60]Fe[30]Si[10] amorphous ribbons with large
thicknesses up to 107 mum were prepared by melt spinning. The hard
magnetic properties of this alloy increase with increasing ribbon
thickness to 107mu m, and the largest values of remanence, coercivity
(iH[c]) and maximum energy product (BH)[max] are 0.15T, 412kA/m and
3.8kJ/m]3[, respectively. The main feature of t his amorphous alloy is
that the hard magnetic properties with high iH[c] are obtained in the
melt-spun amorphous state without crystallinity. The combination of the
large glass-forming ability and hard magnetic properties is important
for the future development of hard magnetic bulk amorphous alloys.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:hard magnetic amorphous alloy, neodymium-iron-sillicon system, high
coercivity, melt spinning technique, thick amorphous ribbon, large
glass-forming ability, relaxed amorphous structure
******************************************************************************
[ID ]:KL97-260
[AUTH]:Harakawa Yoshio, Yamaguchi Hitoshi, Kawamura Taizou, Inoue Akihisa and
Masumoto Tsuyoshi
[TITL]:Chemical Properties of the Flaky Amorphous Copper Alloy Powders (in
Japanese)
[SOUR]:Shikizai (J. Jpn. Soc. Colour Mater.), 70[3] (1997), 155-162
[LAB ]:(2); Teikoku Piston Ring Co., Ltd.; Inoue; Masumoto
[ABST]:When Cu-based amorphous alloy and for pure Cu were immersed in 3wt%NaCl
solution, it was found that the Cu elution was greater for the
amorphous alloy than for the pure Cu. Then, we prepared coating films
containing flaky amorphous Cu powders, pure Cu powders, and Cu[2]O
powders, and immersed in 3wt%NaCl solution up to 360 days. The Cu
elution from the coating film containing amorphous powders was the
greatest of all. It was possible to control the Cu elution by changing
the composition ratio of the amorphous powders and Cu[2]O powders in
the coating films. For antifouling paints, the elution of Cu ion for
long period is required. Thus, the flaky amorphous Cu powders can be
expected for the use as antifouling pigments.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:flaky amorphous powder, copper alloy, chemical property, two-state
quenching process, painting material
******************************************************************************
[ID ]:KL97-261
[AUTH]:Kimura Hisa Michi, Inoue Akihisa, Sasamori Kenichiro and Kawamura
Yoshihito
[TITL]:Elevated-Temperature Strength of Al-7.8 mass%V-4 mass%Fe Alloy
Containing Icosahedral Phase Produced by Extrusion of Atomized Powder
(in Japanese)
[SOUR]:Keikinzoku (J. Jpn. Inst. Light Met.), 47[10] (1997), 539-544
[LAB ]:(2); LDRAM; Inoue; Gijutsu
[ABST]:The bulk material with a size of about phi 8mm times 300mm was produced
by extrusion of gas atomized Al-7.8mass%V-4mass%Fe alloy powder at 623,
673 and 723K. The gas atomized powder consists of icosahedral, fcc-Al
and Al[11]V phases and has a spherical shape with an average diameter
of about 31mu m. The bulk material extruded at 623 K consists of
icosahedral and Al phases and has a high packing density of
approximately 100%. The ultimate tensile strength (sigma[UTS]), plastic
elongation (varepsilon[p]), Vickers hardness (HV) and Young's modulus
(E) at room temperature are 585 MPa, 4.5%, 190 and 84.8GPa,
respectively. And then the sigma[UTS], epsilon[p] and HV at 573K are
305MPa, 5.0% and 90, respectively. The HV remains unchanged even after
holding for 432ks at 573K. The coefficient of thermal expansion is 21.4
times 10]-6[ K]-1[, which is smaller by 15% than that of the 7075-T6
alloy. The bulk materials extruded at 673 and 723K also have the
similar high elevated temperature strength of 291 and 277MPa,
respectively, at the temperature 573K. The extruded bulk materials with
high elevated-temperature strength are expected to develop as a new
type of high strength material.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:aluminum-vanadium-iron alloy, powder, extrusion, mechanical property,
high elevated-temperature strength
******************************************************************************
[ID ]:KL97-262
[AUTH]:Kimura Hisa Michi, Inoue Akihisa, Sasamori Kenichiro and Kawamura
Yoshihito
[TITL]:Extrusion of Atomized Al-7.9mass%V-4mass%Fe Powder Subjected to
Mechanical Grinding and Its Elevated-Temperature Strength (in
Japanese)
[SOUR]:Keikinzoku (J. Jpn. Inst. Light Met.), 47[9] (1997), 487-492
[LAB ]:(2); LDRAM; Inoue; Gijutsu
[ABST]:Mechanical grinding (MG) of gas atomized Al-7.9 mass%V-4 mass%Fe alloy
powder was performed for various times up to 396ks with a low energy
ball mill. The bulk material with a size of phi 8mm times 300mm was
made of the powder subjected to MG for 72ks (72ks-MG powder) by warm
extrusion. The gas atomized powder has a spherical shape with an
average diameter of about 31mu m and the structure consists of Al,
icosahedral and Al[11]V phases. The 72ks-MG powder has a flattened
spherical morphology and the structure consists of icosahedral and Al
phases. The extruded bulk material of the 72ks-MG powder also consists
of icosahedral and Al phases and has a high packing density of
approximately 100%. The tensile strength (sigma[UTS]), plastic
elongation (varepsilon[p]), Vickers hardness (HV) and Young's modulus
at room temperature for the extruded bulk alloy are 588MPa, 3.5%, 180
and 83.4GPa, respectively, and the sigma[UTS], epsilon[p] and HV at
573K are 306MPa, 3.2% and 90, respectively. Thus, the bulk material is
concluded to have high stiffiness and high elevated-temperature
strength.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:aluminum-vanadium-iron alloy, powder, mechanical grinding, mechanical
property
******************************************************************************
[ID ]:KL97-263
[AUTH]:Kimura Hisa Michi, Inoue Akihisa, Sasamori Kenichiro and Kawamura
Yoshihito
[TITL]:Mechanical Properties of Al-Cr Base Alloys Containing Icosahedral Phase
Produced by Extrusion of Atomized Powder (in Japanese)
[SOUR]:Funtai oyobi Funmatsu Yakin (J. Jpn. Soc. Powder Powder Metall.), 44[9]
(1997), 858-863
[LAB ]:(2); LDRAM; Inoue; Gijutsu
[ABST]:Bulk Al[96-x]Cr[3]Ce[1]Co[x](x=1, 1.5, 2) and
Al[95-x]Cr[3]Ce[1]Co[x]TM[1](TM=Zr, Mn, Fe) materials with a dimension
of about phi 8mm times 300mm were produced by extrusion of gas atomized
powders at 523, 573, 623, 673 and 723K. The gas atomized powder has a
spherical shape with an average diameter of about 15mu m, which
consists of icosahedral, Al, Al[9]Co[2] and Al[13]Cr[2] phases. The
bulk Al[94.5]Cr[3]Ce[1]Co[1.5] material extruded at 573K consists of
icosahedral, Al, Al[9]Co[2] and Al[13]Cr[2] phases. The Young's
modulus, Vickers hardness (Hv), ultimate tensile strength and plastic
elongation in the bulk form are 83GPa, 170, 570MPa and 8.4% for
Al[94.5]Cr[3]Ce[1]Co[1.5] and 89GPa, 210, 670MPa and 4.4% for
Al[93.5]Cr[3]Ce[1]Co[1.5]Mn[1], respectively. The Hv at the testing
temperature of 573K for the Al[94.5]Cr[3]Ce[1]Co[1.5] and
Al[92.5]Cr[3]Ce[1]Co[1.5]Zr[2] bulk materials are 55 and 75,
respectively, which are more than twice as large as that for the
7075-T6 alloy.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:aluminum-chromium base alloy, icosahedral phase, gas atomization,
extrusion, mechanical property
******************************************************************************
[ID ]:KL97-264
[AUTH]:Kimura Hisa Michi, Sasamori Kenichiro, Zhang Wei and Inoue Akihisa
[TITL]:Formation of Nonequilibrium Phases in Al-Cr and Al-V Base Alloys by
Mechanical Grinding (in Japanese)
[SOUR]:Funtai oyobi Funmatsu Yakin (J. Jpn. Soc. Powder Powder Metall.), 44
(1997), 207-212
[LAB ]:(2); LDRAM; Gijutsu; Inoue
[ABST]:Mechanical grinding(MG) was performed for Al-Cr and Al-V based alloys
by using the crushed powder of arc-melted Al[94.5]Cr[3]Ce[1]Co[1.5],
Al[96]V[4]Fe[2], Al[91]V[6]Fe[3] and Al[88]V[8]Fe[4] alloys and the
atomized Al[96]V[4]Fe[2] powder. The shape, structure and thermal
stability were examined on powder prepared by MG. The phase of
Al[94.5]Cr[3]Ce[1]Co[1.5] powder change in the order of Al+Al[13]Cr[2]
¨ icosahedral(I) ¨ Al+I+amorphous(Am) ¨ Al+Am by MG. The
nonequilibrium icosahedral or amorphous and Al phases were found t o be
formed for the MG Al-Cr and Al-V base alloys with Al-rich compositions
of 88 to 95%. The formation of the MG-induced nonequilibrium phases
were easier for atomized powder than for the crushed powder.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:aluminum base alloys, mechanical grinding, nonequilibrium phase,
icosahedral phase, amorphous phase
******************************************************************************
[ID ]:KL97-265
[AUTH]:Mizushima Takao, Yamaguchi Ooki, Makino Akihiro and Inoue Akihisa
[TITL]:Structure and Magnetic Properties of Thick-Fe-Based Glassy Alloy
Ribbons (in Japanese)
[SOUR]:Nippon Oyo Jiki Gakkaishi (J. Magn. Soc. Jpn.), 21[4-2] (1997), 613-616
[LAB ]:(2); Central Res. Lab., Alps Electric Co. Ltd.; Inoue
[ABST]:The structure and magnetic properties of melt-spun multicomponent
Fe[72]Ga[2]Al[5]P[11-x]C[6]B[4]Si[x](x=0, 1) with thicknesses from 20
to 440mu m were investigated. The addition of 1at%Si instead of P to
Fe-Ga-Al-P-C-B glassy alloy was found to be effective for extending the
critical thickness to maintain a single amorphous phase (t[max]) and a
supercooled liquid region (Delta T[x]). The values of t[max] and Delta
T[x] are 140mu m and 51K for Fe[72]Ga[2]Al[5]P[11]C[6]B[4], and 160mu m
and 58K for Fe[72]Ga[2]Al[5]P[10]C[6]B[4]Si[1]. The soft magnetic
properties of the Fe-based glassy alloy containing 1at%Si are
comparable to t hose of Fe[78]Si[9]B[13] amorphous ribbon with a
thickness of under 70mu m, and better than those of the same ribbon
with a thickness of over 70mu m. It is therefore expected that the
Fe-based glassy alloy containing 1at%Si will be widely used as a bulky
amorphous material with good soft magnetic properties.
[TYPE]:Amorphous Materials and Quasicrystals
[PROP]:ferromagnetic glassy alloy, rapid solidification, wide supercooled
liquid region, soft magnetic property, sample thickness
******************************************************************************
[ID ]:KL97-266
[AUTH]:Asami Katsuhiko, Moriya Takeshi, Aihara Tomoyasu Jr.
[TITL]:Oxidation Behavior of Sputter-Deposited Cu-Ta Alloys in Air
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 925-929
[LAB ]:(2); LDRAM; Kawazoe; Hashimoto; The Inst. Electric and Magn. Mater.
[ABST]:Surface region of a series of Cu-Ta alloys prepared by
sputter-deposition were characterized by XRD, XPS and AES, Just after
preparation, Ta was enriched in the topmost region as an oxide film
while Cu was enriched under the surface film. The surface film
thickness on alloys increased by a 5 h air-exposure. The surface film
thickness after 5 h exposure to air plotted against alloy composition
had a large maximum at 22 at.% Ta. The surface films consisted of (Cu,
Ta)O[x](OH)[y]EnH[2]O type compound where Cu and Ta were enriched in
low and high Ta alloys, respectively, after 5 h exposure although just
Ta was enriched in the surface film on as-prepared alloys. Enrichment
of Cu in the metallic state under the surface film was observed on all
the alloys. When the oxidation proceeds on low Ta alloys, enriched
metallic Cu under the surface film diffuses through the surface film to
the top surface to form copper oxide film. On high Ta alloys, however,
the Ta-rich surface oxide film on high Ta alloys is protective enough
to prevent diffusion of Cu through the surface film. T he composition
dependence of the oxidation behavior of Cu-Ta alloys in air is largely
related to the protectiveness of the initial oxide film.
[TYPE]:Thin Films and Multilayers
[PROP]:Cu-Ta, thin film, oxidation behavior, surface analysis
******************************************************************************
[ID ]:KL97-267
[AUTH]:Bakhtizin Raouf Z.
[TITL]:Scanning Tunneling Microscopy of Fullerenes on Metal and Semiconductor
Surfaces
[SOUR]:Phys.-Usp., 40[3] (1997), 275-290
[LAB ]:(2); Bashkir State Univ.; Hitachi Ltd.; Sakurai
[ABST]:The current state of the ultra-high vacuum scanning tunneling
microscopy (STM) of fullerene molecules is reviewed with the use of the
authors' work. We focus our work on absorption and reaction of the
C[60] and C[70] fullerenes, separately or in mixture, with
semiconductor [Si(111)-7 times 7 and Si(100)-2 times 1] and metal
[Cu(111)-1 times 1 and Ag(111)-1 times 1] surfaces. By using the STM,
the adsorption geometry and the corresponding reconstruction are
directly observed on these surfaces, and the intramolecular structures
are revealed in high resolution STM images which are analyzed
theoretically within the local charge distribution model. Results on
the ordered growth of fullerene films on metal and semiconductor
surfaces are presented and discussed.
[TYPE]:Thin Films and Multilayers
[PROP]:STM, fullerene, surface
******************************************************************************
[ID ]:KL97-268
[AUTH]:Bakhtizin Raouf Z.
[TITL]:Scanning Tunneling Microscopy of Fullerenes on Metal and Semiconductor
Surfaces (in Russian)
[SOUR]:Usp. Fiz. Nauk, 167[3] (1997), 289-307
[LAB ]:(2); Bashkir State Univ.; Hitachi Ltd.; Sakurai
[TYPE]:Thin Films and Multilayers
[PROP]:STM, fullerene, surface
******************************************************************************
[ID ]:KL97-269
[AUTH]:Chen Yefan, Bagnall Darren M.
[TITL]:Growth of ZnO Single Crystal Thin Films on c-Plane(0001) Sapphire by
Plasma Enhanced Molecular Beam Epitaxy
[SOUR]:J. Cryst. Growth, 181[1/2] (1997), 165-169
[LAB ]:(2); Yao; Suezawa; Hiraga; Dept. of Phys., Tohoku Univ.
[ABST]:ZnO single crystal thin films were grown by plasma enhanced molecular
beam epitaxy on (0 0 0 1) sapphire. The growth modes of ZnO epilayers
were investigated by reflection high-energy electron diffraction. A
transition from two-dimensional nucleation to three-dimensional
nucleation is found at the initial growth stage. Optical properties of
the films, studied by photoluminescence spectroscopy, exhibit a
dominant bound exciton emission at 3.361eV at 4K, and a deep level
emission centered at 2.42eV which is associated with either impurities
or native defects. The deep level emission which is successfully
suppressed to 1/500 of intensity of the excitonic emission. Fabrication
of these high-quality ZnO epilayers had lead to observation of
stimulated emission at room temperature.
[TYPE]:Thin Films and Multilayers
[PROP]:ZnO, film, plasma, molecular beam epitaxy, sapphire
******************************************************************************
[ID ]:KL97-270
[AUTH]:Fujiwara Yuji, Masaki Tsugihiko, Yu Xiang You, Sakurai Masaki,
Tsunashima Shigeru, Iwata Satoshi and Suzuki Kenji
[TITL]:Structural and Magnetic Anisotropy of Tb/Fe Multilayers
[SOUR]:Jpn. J. Appl. Phys., 36[8] (1997), 5097-5102
[LAB ]:(2); Dept. of Elect., Nagoya Univ.; Suzuki
[ABST]:Local structural anisotropy of Tb/Fe multilayers (MLs) was investigated
by extended X-ray absorption fine structure (EXAFS) spectroscopy.
Quantitative analysis of Fe EXAFS signals was performed to estimate the
coordination number related to the structural anisotropy. A difference
in the Fourier-transformed Fe EXAFS spectra between two incident
polarized light directions has indicated that considerable anisotropy
of atomic pair ordering exists in the MLs prepared by sputtering. It
was further found that the variation of the structural anisotropy well
corresponds to the magnitude of the perpendicular magnetic anisotropy,
which changes depending on the bilayer periods and the preparation
condition.
[TYPE]:Thin Films and Multilayers
[PROP]:Tb/Fe, EXAFS, multilayer, magnetic anisotropy, structural anisotropy
******************************************************************************
[ID ]:KL97-271
[AUTH]:Grunberg Peter, Schaefer Markus, Takanashi Koki, Rucker Uhrich, Nassar
J and Mertig Ingrid
[TITL]:Experiments on Interlayer Exchange Coupling
[SOUR]:Acta Phys. Pol. A, 91[1] (1997), 7-14
[LAB ]:(2); Forschungszentrum Julich Germany; Fujimori; Inst. fur Theoretische
Phys. Technische Univ. Dresden
[ABST]:The results of various experiments on interlayer exchange coupling will
be reviewed. After a general discussion of the theoretical
understanding we deal first with 90‹-type coupling and show that two
mechanisms proposed by Slonczewski can explain our measured data. We
furthermore study the coupling of Fe films across Cu[x]Au[1-x] alloys.
For the composition with x=0.5, the coupling strength strongly
increases with annealing. We believe that this is due to an
order-disorder structural transformation in the Cu[x]Au[1-x] alloy.
Finally, we present results on epitaxially grown bilayers Fe/EuS(100)
and trilayers Fe/EuS/Fe(100). In the latter at room temperature we
observe a strong decrease in the coupling strength as a function of the
interlayer thickness, with a characteristic length of about 0.1nm. At
low temperatures in the bilayer we find an antiferromagntic coupling
between Fe and the adjacent ferromagnetic EuS.
[TYPE]:Thin Films and Multilayers
[PROP]:Fe/Au, CuAu alloy, Fe/EuS, interlayer exchange coupling
******************************************************************************
[ID ]:KL97-272
[AUTH]:Hayakawa Yasuo, Makino Akihiro, Fujimori Hiroyasu and Inoue Akihisa
[TITL]:High Resistive Nanocrystalline Fe-M-O (M=Hf, Zr, Rare-Earth Metals)
Soft Magnetic Films for High-Frequency Applications
[SOUR]:J. Appl. Phys., 81[8] (1997), 3747-3752
[LAB ]:(2); Alps Co.; Inoue; Fujimori
[ABST]:Microstructure, soft magnetic properties, and applications of high
resistive Fe-M-O (M=Hf, Zr, rare-earth metals) were studied. The Fe-M-O
films are composed of bcc nanograins and amorphous phases with larger
amounts of M and O elements which chemically combine each other.
Consequently, the amorphous phases have high electrical resistivity.
The compositional dependence of magnetic properties, electrical
resistivity, and structure have been almost clarified. For example, the
high magnetization of 1.3T, high permeability of 1400 at 100MHz and the
high electrical resistivity of 4.1mu Omega m are simultaneously
obtained for as-deposited Fe[62]Hf[11]O[27] nanostructured film
fabricated by rf reactive sputtering in a static magnetic field.
Furthermore, Co addition to Fe-M-O films improves the frequency
characteristics mainly by the increase in the crystalline anisotropy of
the nanograins. The Co[44.3]Fe[19.1]Hf[14.5]O[22.1] film exhibits the
quality factor (Q=mu'/mu") of 61 and the mu' of 170 at 100MHz as well
as the high Is of 1.1T. This frequency characteristics is considered to
be superior to the other films already reported. The films also exhibit
high corrosion resistance in an isotonic sodium chloride solution.
Therefore, these films enable us to realize the high-frequency magnetic
devices, such as thin-film inductors and transformers for
microswitching converters and ultrahigh-density recording heads.
[TYPE]:Thin Films and Multilayers
[PROP]:nanocrystalline Fe-based film, high electrical resistivity,
permeability, soft magnetism, high-frequency application
******************************************************************************
[ID ]:KL97-273
[AUTH]:Heck C.
[TITL]:Negative Gold Ion Beam Production and Its Applications
[SOUR]:IONICS, 23[7-Suppl.1] (1997), 119-123
[LAB ]:(2); Res. Lab. for Surf. Sci., Faculty of Sci., Okayama Univ.; Osaka
National Res. Inst. AIST(ONRI); Tanino
[ABST]:The ion beam deposition (IBD) technology has been applied for
development of an apparatus for deposition of low-energy, mass-analyzed
ions under ultra-high-vacuum conditions so that deposition of isotope
resolved, ultra-high purity materials of a variety of ion species is
possible. The ion beam energy can be varied from 10eV to 20keV, which
allows a systematic study on the influence of the beam energy on thin
film growth processes. A study of the application of low-energy,
mass-analyzed negative Au ions for producing Au and Au-compound films
on various substrate types (Si, C) is reported. Influence of ion beam
energy as well as of substrate type on the structure of grown films has
been analyzed.
[TYPE]:Thin Films and Multilayers
[PROP]:gold, negative ion beam, thin film
******************************************************************************
[ID ]:KL97-274
[AUTH]:Heck Chaire, Chayahara Akiyoshi, Tsubouchi Nobuteru, Horino Yuji, Fujii
Kanenaga, Iwami Motohiro and Abiko Kenji
[TITL]:Formation of Thin Au Films Using Negative-Ion-Beam Deposition
[SOUR]:Phys. Status Solidi A, 160[2] (1997), 591-597
[LAB ]:(2); Osaka National Res. Inst.; Res. Lab. for Surf. Sci., Faculty of
Sci., Okayama Univ.; Tanino
[ABST]:An apparatus for the deposition of positive and negative ions (PANDA)
has been developed. This facility permits single-beam deposition or
simultaneous positive- and negative-ion-beam deposition of a variety of
species. Low-impurity-level films are expected to be produced with
ion-beam deposition due to the combination of beam mass-analysis and
ultra-high-vacuum conditions. A systematic study of the influence of
beam energy on thin-film growth processes is also possible with PANDA
due to the fact that the energy of both beams can be varied over a wide
range, from 10eV to 20keV. A study of gold films produced with
deposition of low-energy (50 to 200eV) Au]-[ ion beams produced with
PANDA is reported in detail. The Au films have been analyzed with
several techniques, such as Rutherford backscattering spectrometry,
X-ray diffraction and high-resolution scanning electron microscopy.
[TYPE]:Thin Films and Multilayers
[PROP]:gold, negative-ion-beam, thin film
******************************************************************************
[ID ]:KL97-275
[AUTH]:Ishihara Masahito, Mizuseki Hiroshi, Kawazoe Yoshiyuki and Ohta Norio
[TITL]:A Recording Process Simulation for Double-Layered Magneto-Optical Disk
[SOUR]:IEEE Trans. Magn., 33[5] (1997), 4149-4151
[LAB ]:(2); Kawazoe; LDRAMD; Hitachi Maxell
[ABST]:Magnetic Multi-Valued (MMV) recording process is studied by numerical
simulation including thermomagnetic effect. A medium, which consists of
PtCo capping layer coupled to TbFeCo recording layer, switches the
signal of Kerr rotation angle responding to the external field in four
levels. The time evolution of generated pattern of recording mark is
calculated by extending the previous magneto-optical (MO) recording
simulation for single layer system.
[TYPE]:Thin Films and Multilayers
[PROP]:TbFeCo, magnetic multivalued recording, Kerr rotation angle, hysteresis
loop
******************************************************************************
[ID ]:KL97-276
[AUTH]:Itoh Hiroyoshi, Inoue Jun-ichiro and Maekawa Sadamichi
[TITL]:Perpendicular Electrical Transport through a Single Random Interface
[SOUR]:Physica B, 237-238 (1997), 264-266
[LAB ]:(2); Nagoya Univ.; Maekawa
[ABST]:Conductance for perpendicular currents through a single random
interface is studied. Analytic expression for the conductance is
formulated within the single-site coherent potential approximation. It
is shown that the vertex correction describes diffusive scattering
which plays an important role in t he conductance as predicted by
Brataas and Bauer even in the present case.
[TYPE]:Thin Films and Multilayers
[PROP]:giant magnetoresistance, multilayer, tunneling junction
******************************************************************************
[ID ]:KL97-277
[AUTH]:Izumiya Koichi, Akiyama Eiji, Habazaki Hiroki, Kumagai Naokazu,
Kawashima Asahi and Hashimoto Koji
[TITL]:Effects of Additional Elements on Electrocatalytic Properties of
Thermally Decomposed Manganese Oxide Electrodes for Oxygen Evolution
from Seawater
[SOUR]:Mater. Trans., JIM, 38[10] (1997), 899-905
[LAB ]:(2); Hashimoto; Daiki Eng. Co. Ltd.
[ABST]:Manganese oxide electrodes with some additives enhance oxygen evolution
efficiency in seawater electrolysis. Electrodes were prepared by a
thermal decomposition method. IrO[2]-coated titanium (IrO[2]/Ti
electrode) was used as the substrate on which manganese oxide
(MnO[X]/IrO[2]/Ti) and oxide mixtures of manganese and iridium,
ruthernium, platinum, iron, cobalt, nickel, tin, lanthanum, cerium or
molybdenum ((Mn-M)O[X]/IrO[2]/Ti electrode, M: additives) were coated.
The oxygen evolution efficiency of the MnO[X]/IrO[2]/Ti electrode was
68-70%. The addition of small amounts of nickel, cobalt, iron or tin
enhanced the oxygen evolution efficiency. However the addition of
excess amounts of these elements and additions of noble metals, cerium
or lanthanum were detrimental for the oxygen evolution. Among the
additives examined, molybdenum was the most effective additional
element to increase the oxygen evolution efficiency. The addition of a
small amount of molybdenum leads to a remarkable increase in the oxygen
evolution efficiency up to 91%. The formation of a single phase
Mn[2]O[3] with molybdenum ions seems to be responsible for the high
efficiency for oxygen evolution.
[TYPE]:Thin Films and Multilayers
[PROP]:Mn[2]O[3], Mo, seawater electrolysis, oxygen evolution anode, oxygen
evolution efficiency, thermal decomposition
******************************************************************************
[ID ]:KL97-278
[AUTH]:Kaya Kiyoshi, Takahashi Hiroshi, Shibata Yoshihiko, Kanno Yasuhito and
Hirai Toshio
[TITL]:Synthesis and Surface Acoustic Wave Properties of AlN Thin Films
Fabricated on (001) and (110) Sapphire Substrates Using Chemical Vapor
Deposition of AlCl[3]-NH[3] System
[SOUR]:Jpn. J. Appl. Phys., 36[5A] (1997), 2837-2842
[LAB ]:(2); Electronics Mater. and Devices Lab., Asahi Chem. Industry Co.,
Ltd.; Hirai
[ABST]:Thin films of AlN were prepared on sapphire C- and A-plane by chemical
vapor deposition. Crystal orientations, oxygen impurity contents and
surface acoustic wave properties (SAW) of the films were investigated.
Under optimized conditions, epitaxial AlN films were deposited and the
crystal orientation relationships were (001)[110]AlN parallel
(001)[110]Al[2]O[3] and (001)[110]AlN parallel (110)[110]Al[2]O[3]. The
crystal orientation of the AlN films decreased as the thickness of the
films increased slightly, and the oxygen impurity content was less than
1atm% for both systems. The dependences of SAW velocity (V[s]) and the
temperature coefficient of the center frequency (tau[f]) on the film
thickness were measured, and tau[f] was found to increase as the film
thickness increased for all measurement directions; however,
zero-temperature coefficient was not achieved.
[TYPE]:Thin Films and Multilayers
[PROP]:AlN, CVD, SAW properties, piezoelectricity, crystal orientation
******************************************************************************
[ID ]:KL97-279
[AUTH]:Masuda Yoichiro, Fujita Shigetaka, Baba Akira, Masumoto Hiroshi, Nagata
Kunihiro and Hirai Toshio
[TITL]:Synthesis of BaTiO[3] Thin Films Substituted with Hafnium and Zirconium
by a Laser Ablation Method Using the Fourth-Harmonic Wave of a YAG
Laser
[SOUR]:Jpn. J. Appl. Phys., 36 (1997), 5834-5839
[LAB ]:(1); Dept. of Elect. Eng., Faculty of Eng., Hachinohe Inst. of
Technol.; Dept. of Elect. Eng., the National Defense Acad.; Hirai
[ABST]:For the first time to our knowledge, BaTi(Hf[0.5]Zr[0.5])O[3] (BTHZ)
thin films have been successfully synthesized using a laser ablation
technique that employs the fourth harmonic wave of a pulsed YAG
(FHG-YAG) laser. The BTHZ thin film with a preferred orientation in the
c-axis was prepared under an oxygen gas pressure of 3 Pa at 800Ž.
Chemical bonds in the BTHZ compounds can easily be broken by
irradiation at an optical energy of 7.47 times 10]-19[ J and an optical
power density of 300 mJ/cm]2[. Crystallinity of the deposited films is
dominated by the mean free path of each element.
[TYPE]:Thin Films and Multilayers
[PROP]:ferroelectrics, BaTi[0.91](Hf[0.5]Zr[0.5])[0.09]O[3], BaTiO[3] family,
thin films, YAG laser ablation
******************************************************************************
[ID ]:KL97-280
[AUTH]:Masuda Yoichiro, Masumoto Hiroshi, Baba Akira, Kidachi Yuuki and Hirai
Toshio
[TITL]:Ferroelectric Properties of Ba[2]NaNb[5]O[15] Films by RF Magnetron
Sputtering Method
[SOUR]:Ferroelectrics, 195 (1997), 297-304
[LAB ]:(1); Dept. of Electrical Eng., Faculty od Eng., Hachinohe Inst. of
Technol.; Hirai
[ABST]:The deposition ratio (Ba:Na:Nb) of tungsten-bronze type thin film
ferroelectrics depend on the sputtering conditions. The dielectric
constant, dielectric loss factor are 889 and 0.029 at room temperature.
The leakage current density is about 100mu A/cm]2[ at 1MV/cm. The
remanent polarization and coercive field are 2.39mu C/cm]2[ and
87.33kV/cm, and the SHG coefficient d is about 2.51 times 10]-13[ m/V,
respectively.
[TYPE]:Thin Films and Multilayers
[PROP]:Ba[2]NaNb[5]O[15], RF sputtering, D-E hysteresis, SHG
******************************************************************************
[ID ]:KL97-281
[AUTH]:Mitani Seiji, Fujimori Hiroyasu and Ohnuma Shigehiro
[TITL]:Spin-Dependent Tunneling Phenomena in Insulating Granular Systems
[SOUR]:J. Magn. Magn. Mater., 165 (1997), 141-148
[LAB ]:(1); Fujimori; The Res. Inst. of Electric and Magn. Mater.
[ABST]:We studied giant magnetoresistance (GMR) and the related properties in
Co-Al-O insulating granular films prepared by reactive sputtering.
Microstructural observation revealed that the films were composed of Co
base metallic granules and Al[2]O[3] base insulating network-like
boundaries. The GMR varied as a function of oxygen content (or
Co/Al[2]O[3] ratio) and it took a maximum of 8% at room temperature and
17% at 4.2K for a Co[52]Al[20]O[28] film, accompanying huge specific
electrical resistivities of the order of 10]5[ - 10]6[ mu Omega cm. It
has been considered that the observed GMRs are attributed to a
spin-dependent tunneling and that the spin diffusion of electrons
during tunneling plays an important role of the composition dependence
of GMR. In addition, it has been noted that the temperature dependence
of GMR is smaller than the T]-1[ dependence predicted theoretically by
Helman et al. but rather close to the theory by Inoue et al.
[TYPE]:Thin Films and Multilayers
[PROP]:Co-Al-O, spin-dependent tunneling, giant magnetoresistance, insulating
granular system, reactive sputtering
******************************************************************************
[ID ]:KL97-282
[AUTH]:Mitani Seiji, Takanashi Koki, Shigemoto Yasutaka and Fujimori Hiroyasu
[TITL]:Coherent Layered Structures in Fe/Au Monatomic Multilayers with
Addition of Fractional Atomic Layers
[SOUR]:Jpn. J. Appl. Phys., 36[8A] (1997), L1045-L1047
[LAB ]:(1); Fujimori
[ABST]:Fractional numbers of atomic layers have been introduced intentionally
into Fe/Au monatomic multilayers in order to investigate the effect of
the deviation from monatomic layer thickness on the layered structure.
We prepared [Fe(1 + delta ML)/Au(1 + delta ML)] multilayers with the
fraction delta=0, 0.25 and 0.5, where ML represents monatomic layer
thickness. The superlattice (001) peak associated with the L1[0]
ordered structure is observed in the X-ray diffraction profile for
delta=0. For delta=0.25 and 0.5, on the other hand, the superlattice
(001) peak is split into a couple of sharp peaks. The appearance of
those two peaks indicates the formation of coherent layered structure
with long-range periodicity, even for samples with fractional atomic
layers.
[TYPE]:Thin Films and Multilayers
[PROP]:Fe/Au, monatomic multilayer, fractional atomic layer, coherent layered
structure, X-ray diffraction
******************************************************************************
[ID ]:KL97-283
[AUTH]:Motokawa Mitsuhiro, Wang Zhong Jie, Mitsudo Seitaro, Watanabe Kazuo,
Saito Kesami and Fujimori Hiroyasu
[TITL]:Spin Wave Resonance in Co/Cu Multilayers
[SOUR]:Physica B, 237-238 (1997), 247-248
[LAB ]:(2); Motokawa; HFLSM; Gijutsu; Fujimori
[ABST]:Ferromagnetic resonance (FMR) has been performed on Co/Cu multilayers
in X-band. In the perpendicular external field configuration, a series
of spin wave modes and a set of bulk and surface modes have been
observed in ferromagnetically coupled and antiferromagnetically coupled
and antiferromagnetically coupled cases, respectively.
[TYPE]:Thin Films and Multilayers
[PROP]:FMR, multilayers, spin wave
******************************************************************************
[ID ]:KL97-284
[AUTH]:Noya Atsushi, Takeyama Mayumi, Sasaki Katsutaka, Aoyagi Eiji and Hiraga
Kenji
[TITL]:Transmission Electron Microscopy of the Sequence of Phase Formation in
the Interfacial Solid-Phase Reactions in Ta/Si Systems
[SOUR]:J. Vac. Sci. Technol., A, 15[2] (1997), 253-257
[LAB ]:(1); Dept. of Electrical and Electronic Eng. Faculty of Eng., Kitami
Inst. Technol.; Hiraga
[ABST]:The interfacial reaction of Ta thin films on (100) Si was investigated
by high-resolution transmission electron microscopy. An amorphous layer
was observed at the as-deposited Ta/Si interface. A phase of Ta[5]Si[3]
was first found to form at the interface between a Ta overlayer and the
amorphous layer after annealing at 560Ž for 1 h. Annealing at 630Ž
for 1 h led to the formation of another interlayer due to the
outdiffusion of Si between the amorphous layer and Si. The phase in
this interlayer transformed from a metastable one to TaSi[2] due to
annealing at 680Ž for 1h. The first nucleation of Ta[5]Si[5] at the
interface between Ta and the amorphous layer implies that the initially
formed amorphous layer has a metal-rich composition close to
Ta[5]Si[3]. The formation of the interlayer between the amorphous layer
and Si prior to the nucleation of TaSi[2] was considered as a result of
a kinetic constraint to favor the nucleation of TaSi[2].
[TYPE]:Thin Films and Multilayers
[PROP]:Ta/Si system, solid-phase reaction, transmission electron microscopy,
interfacial reaction
******************************************************************************
[ID ]:KL97-285
[AUTH]:Oomi Gendo, Sakai Takeshi, Uwatoko Yoshiya, Takanashi Koki and Fujimori
Hiroyasu
[TITL]:Magnetoresistance of Magnetic Multilayers at High Pressure
[SOUR]:Physica B, 239[1&2] (1997), 19-28
[LAB ]:(1); Dept. of Mechanical Eng. and Mater. Sci., Faculty of Eng.,
Kumamoto Univ.; Ariake National College of Technol.; Dept. of Phys.,
Faculty of Sci., Saitama Univ.; Fujimori
[ABST]:In the present work we report the effect of pressure on the giant
magnetoresistance (GMR) of several magnetic multilayers (MML). First,
we show the experimental results of the effect of pressure on the
electrical resistance and magnetoresistance (MR) of Fe/Cr MML having
different thickness of Cr layers t[Cr] layers t[Cr]. It is found that
the GMR of the samples near the first peak (t[Cr]=9.5 and 11 angstrom)
is affected strongly by applying pressure reflecting the unstable
electronic structure but the effect of pressure on the MR of the sample
between peaks (t[Cr]=15.2 angstrom) is very small. The saturation field
H[s] of Fe/Cr MML increases with pressure. These results are compared
with those of other MMLs such as Fe/Cu and Co/Cu systems. Finally, the
importance of the magnetic state in the paramagnetic layers or
interfacial roughness is pointed out to understand the results in the
present work.
[TYPE]:Thin Films and Multilayers
[PROP]:Fe/Cr, Co/Cu, magnetic multilayers, magnetoresistance, pressure effect
******************************************************************************
[ID ]:KL97-286
[AUTH]:Peng Dong Liang, Sumiyama Kenji and Suzuki Kenji
[TITL]:Effect of Heat Treatment on the Structure and Magnetic Properties of
Fe-N and Fe-Ti-N Alloy Films
[SOUR]:J. Alloys Compd., 255 (1997), 50-54
[LAB ]:(1); Suzuki
[ABST]:Fe-N and Fe-Ti-N alloy films have been prepared by reactive sputtering.
The structure and magnetic properties of the Fe-Ti-N and Fe-N films
have been studied as a function of the N[2] flow rate R(N[2]) and
annealing temperature T[A] by X-ray diffraction (XRD) and a vibrating
sample magnetometer. The as-prepared and annealed Fe-N films consist of
the alpha-Fe and Fe[4]N phases but the Fe-Ti-N films are composed of
the alpha-Fe and Ti[2]N phases. The coercivity, Hc, of the Fe-N films
changes drastically with R(N[2]) and T[A], while that of the Fe-Ti-N
films does not change with T[A] up to 500Ž. These results indicate
that the addition of Ti suppresses the formation of iron nitride phases
and improves the thermal stability of Fe-N films.
[TYPE]:Thin Films and Multilayers
[PROP]:Fe-N, Fe-Ti-N, magnetic property, structure, annealing
******************************************************************************
[ID ]:KL97-287
[AUTH]:Sakai Takeshi, Oomi Gendo, Okada Kunihide, Takanashi Koki, Saito Kesami
and Fujimori Hiroyasu
[TITL]:Difference between the Giant Magnetoresistance of Fe/Cu and Co/Cu
Magnetic Multilayers under High Pressure
[SOUR]:Physica B, 239[1&2] (1997), 53-55
[LAB ]:(1); Ariake National College of Technol.; Dept. of Mechanical Eng. and
Mater. Sci., Faculty of Eng., Kumamoto Univ.; Dept. of Phys., Faculty
of Sci., Kumamoto Univ.; Fujimori; Gijutsu
[ABST]:The giant magnetoresistance (GMR) of T/Cu(T=Fe, Co) magnetic
multilayers (MML) has been investigated under high pressure at 4.2, 77K
and room temperature. It is found that the magnitudes of GMR at 77K and
at room temperature for both MMLs are almost independent of pressure up
to 0.8GPa, but 9.2% decrease in GMR is observed at 4.2K under the
pressure of 2GPa. On the basis of these results, the difference between
GMR for Fe/Cu and Co/Cu MMLs under high pressure is discussed briefly.
[TYPE]:Thin Films and Multilayers
[PROP]:Fe/Cu, Co/Cu, magnetic multilayers, giant magnetoresistance, high
pressure
******************************************************************************
[ID ]:KL97-288
[AUTH]:Sakai Takeshi, Oomi Gendo, Okada Kunihide, Takanashi Koki, Saito Kesami
and Fujimori Hiroyasu
[TITL]:Effect of Pressure on the Giant Magnetoresistance of Fe/Cu Magnetic
Multilayer
[SOUR]:Physica B, 237-238 (1997), 275-277
[LAB ]:(1); Ariake National College of Technol.; Dept. of Mechanical Eng. and
Mater. Sci., Faculty of Eng., Kumamoto Univ.; Fujimori; Gijutsu
[ABST]:Giant magnetoresistance (GMR) of a [Fe 10.1angstrom / Cu
13.7angstrom][15] magnetic multilayer (Fe/Cu MML) has been measured at
room temperature, 77 and 4.2K under high pressure. It is found that the
magnitude of GMR of Fe/Cu MML is almost independent of pressure at room
temperature and 77K, while it decreases with increasing pressure at
4.2K. The result of Fe/Cu MML is compared with that of Co/Cu MML.
[TYPE]:Thin Films and Multilayers
[PROP]:Fe/Cu, multilayer, giant magnetoresistance, pressure effect
******************************************************************************
[ID ]:KL97-289
[AUTH]:Suzuki Yoshishige, Katayama Toshikazu, Geerts Wim, Grunberg Peter,
Takanashi Koki, Schreiber Reinert, Bruno Pactrick and Yuasa Shinji
[TITL]:Magneto-Optical Effects of Ultrathin Ferro-, Antiferro- and
Non-Magnetic Films
[SOUR]:Mater. Res. Soc. Symp. Proc., 475 (1997), 227-237
[LAB ]:(2); JRCAT-NAIR; Electrotechnical Lab.; Forschungszentrum Juenlich
GmbH; Fujimori; Univ. Paris-Sud
[ABST]:Thickness dependence of the magneto-optical Kerr effects (MOKE) in
ultrathin ferromagnetic films, antiferromagnetic films and nonmagnetic
films were measured carefully employing wedge shaped samples at room
temperature. The oscillations of the polar Kerr ellipticity with
respect to the film thickness and its energy dependence were observed
for the Fe and Au ultrathin films, and revealed a formation of
spin-polarized quantum well states both in the bcc-Fe (100) layers and
the fcc-Au(001) layers. On the other hand, bcc-Cr(100) ultrathin layers
grown on 3ML of Fe(100) layer showed about 2ML period oscillation of
the polar MOKE for the photon energy in between 2.25 and 3.75eV,
indicating an existence of a long range antiferromagnetic order. The Cr
film also showed energy dependent oscillation peaks for the very thin
region (d[10ML). The longitudinal MOKE were measured also for Cr
samples, and revealed 2ML period oscillation. The mechanism of the MOKE
oscillations is discussed from the view points of quantum size effects
and the antiferromagnetic order.
[TYPE]:Thin Films and Multilayers
[PROP]:Fe, Au, Cr, magneto-optical Kerr effect, quantum size effect
******************************************************************************
[ID ]:KL97-290
[AUTH]:Suzuki Yoshishige, Katayama Toshikazu, Takanashi Koki, Schreiber
Reinert, Grunberg Peter and Tanaka Kazunobu
[TITL]:The Magneto-Optical Effect of Cr(001) Wedged Ultrathin Films Grown on
Fe(001)
[SOUR]:J. Magn. Magn. Mater., 165 (1997), 134-136
[LAB ]:(2); Joint Res. Center for Atom Technol.; Electrotechnical Lab.
Tsukuba; IFF, Forschungszentrum Julich Germany; Fujimori
[ABST]:The magnetic and electronic properties of wedge-shaped Cr(001)
ultrathin overlayers grown on an Fe(001) layer were investigated using
the magneto-optical effect. Precise measurements of the thickness
dependence of the saturation Kerr ellipticity at room temperature show
clear oscillations caused by the antiferromagnetic order and/or the
quantum size effect in the Cr layer. The short period, Lambda approx
2ML, was observed clearly for photon energy between 2.25 and 3.75eV and
was constant in this energy range. The long period oscillation observed
from 3.25 to 4.75eV changes its period.
[TYPE]:Thin Films and Multilayers
[PROP]:Cr, Fe, magneto-optical Kerr effect, quantum size effect
******************************************************************************
[ID ]:KL97-291
[AUTH]:Tsuchiya Yasuaki, Kosuge Koji, Yamaguchi Sadae and Nakayama Noriaki
[TITL]:Exchange Anisotropy of CrN[x]/FeN[y]/CrN[x] Trilayer Thin Films
Prepared by Reactive Sputtering
[SOUR]:Mater. Trans., JIM, 38[2] (1997), 91-98
[LAB ]:(1); Division of Chem., Guraduate School of Sci., Kyoto Univ.;
Yamasada; Dept. of Adv. Mater. Sci. and Eng., Faculty of Eng. Yamaguchi
Univ.
[ABST]:The exchange magnetic anisotropy of CrN[x]/FeN[y]/CrN[x] trilayer films
(x=1.0 or 1.2, and y=0.27) has been investigated by means of
magnetization measurements. M-H loops of samples composed of
nearly-stoichiometric CrN[1.0] with T[N]=260K show exchange biasing
shift H[eb] below 200K. The uniaxial anisotropy energy per film area is
3.0 times 10]-4[ J/m]2[ at 5K. For samples with 20nm-thick FeN[0.27]
layer and CrN[1.0] layers thicker than 20nm, the values of H[eb] at 5K
are almost 13.5kA/m. The samples composed of over-stoichiometric
CrN[1.2] show H[eb] below 50K, indicating that T[N] of
over-stoichiometric CrN[1.2] is much lower than that of
nearly-stoichiometric CrN[1.0]. The values of H[eb] for stoichiometric
and over-stoichiometric systems are nearly equal below 20K and, in this
temperature range, H[eb] shows unusual enhancements with decreasing
temperature. It is suggested that the nitrogen composition at the
interface region of stoichiometric CrN layer is over-stoichiometric.
[TYPE]:Thin Films and Multilayers
[PROP]:chromium nitride, iron nitride, thin films, magnetic anisotropy,
interface structure
******************************************************************************
[ID ]:KL97-292
[AUTH]:Tsunekawa Shin, Fukuda Tsuguo, Ozaki Toru, Yoneda Yasuhiro and Terauchi
Hikaru
[TITL]:Atomic Force and Scanning Electron Microscopic Observations of Surface
and Domain Structures of BaTiO[3] Films and Bulk Crystals
[SOUR]:Appl. Phys. Lett., 71[11] (1997), 1486-1488
[LAB ]:(2); Fukuda; Hiroshima Univ.; Kwansei-Gakuin Univ.
[ABST]:Tapping-mode atomic force and in situ scanning electron microscopic
observations of surface and ferroelectric domain structure are
performed, respectively, for BaTiO[3] crystalline films grown on
{100}SrTiO[3] substrates by molecular beam epitaxy and for bulk
crystals prepared by the top-seeded solution growth technique.
Reconstructionlike structures of very long periods are found for the
first time in both thin (20nm) and thick (1000nm) films. A dependence
of the end size of pole-type 180‹ domains observed in films and bulk
crystals on their thickness agrees with the relation expected
theoretically.
[TYPE]:Thin Films and Multilayers
[PROP]:barium titanate, 180-degree domain, atomic force microscopy, scanning
electron microscopy, crystalline film
******************************************************************************
[ID ]:KL97-293
[AUTH]:Wang Jian Tao, Li Zhi Qiang and Kawazoe Yoshiyuki
[TITL]:First-Principles Calculation of the Structural and Magnetic Properties
of Fe/Au and Cr/Au Monatomic Multilayers
[SOUR]:J. Phys.: Condens. Matter, 9[22] (1997), 4549-4556
[LAB ]:(3); Kawazoe
[ABST]:The structural and magnetic properties of Fe/Au and Cr/Au monatomic
multilayers with the tetragonal L1[0] ordered structure in
paramagnetic, ferromagnetic, and antiferromagnetic states are studied
by means of the self-consistent full-potential linearized
augmented-plane-wave method. It is found that the L1[0] ordered Fe/Au
monatomic multilayer has a ferromagnetic ground state with an enhanced
moment of 2.76mu[B] of Fe. On the other hand, the L1[0] ordered Cr/Au
monatomic multilayer has and antiferromagnetic ground state with a
large local moment 3.18mu[B] of Cr. By total energy minimization, the
lattice constants for their ground states are determined.
[TYPE]:Thin Films and Multilayers
[PROP]:Fe/Au, Cr/Au, Ll[0], FLAPW, magnetic moment
******************************************************************************
[ID ]:KL97-294
[AUTH]:Xue Qi Kun, Xue Qi Zhen, Hasegawa Yukio, Tsong Ignatius S.T
[TITL]:Initial Stages of Cubic GaN Growth on the GaAs(001) Surface Studied by
Scanning Tunneling Microscopy
[SOUR]:Jpn. J. Appl. Phys., 36 (1997), L1486-L1489
[LAB ]:(2); Sakurai; Arizona State Univ.
[ABST]:Nitridation of the GaAs(001) surfaces using an N-atom radio-frequency
plasma source is investigated by in situ scanning tunneling microscopy
(STM). Atomically flat (3 times 3) nitrided surfaces commensurate and
coherent with the substrate have been achieved on the As-rich (2 times
4) and (2 times 6) surfaces. Nitridation proceeds via competing
mechanisms of (3 times 3) ordering and step-etching caused by the
N-atoms. The former simply involves N-As exchange, which does not
require significant morphology modification, whereas the latter causes
the roughening of the substrate under the standard GaN growth
conditions. On the Ga-rich surface, the GaN islands immediately form at
the step-edges, suggesting the possibility of self-assembled
nanostructures of GaN.
[TYPE]:Thin Films and Multilayers
[PROP]:GaN, GaAs, STM
******************************************************************************
[ID ]:KL97-295
[AUTH]:Mitani Seiji, Shintani Yasutaka, Ohnuma Shigehiro and Fujimori Hiroyasu
[TITL]:Giant Magnetoresistance and Hall Effect in Fe-Based Metal-Oxide
Granular Thin Films (in Japanese)
[SOUR]:Nippon Oyo Jiki Gakkaishi (J. Magn. Soc. Jpn.), 21[4-2] (1997), 465-468
[LAB ]:(2); Fujimori; The Res. Inst. of Electric and Magn. Mater.
[ABST]:Tunnel-type giant magnetoresistance (GMR) and the Hall effect in
Fe-based metal-oxide granular thin films of Fe-Mg-O and Fe-Al-O were
investigated. While the magnetoresistance Delta rho/rho[0](%) of the
films at RT was smaller than about 4%, it was remarkably enhanced at
lower temperatures, with values of 14% for Fe[25]Mg[32]O[43] and 25%
for Fe[44]Al[17]O[39] at 4.2K. These MR values are comparable to or
larger than that for Co-Al-O granular thin films at 4.2K (17% at
maximum). This result supports the current understanding that the
magnitude of tunnel-type GMR is dependent on the spin polarization. The
extraordinary Hall coefficients R[s] was successfully measured in the
metallic conduction region of rho[0] (mu Omega cm)[10]5[ for Fe-Mg-O.
The R[s] vs. resistivity rho[0] curve can be fitted by R[s] propto
rho[1.0]]0[ for rho[0][10]3[, implying skew scattering. However, R[s]
deviates greatly below the fitting line for 10]3[[rho[0][10]5[ near the
tunnel conduction region.
[TYPE]:Thin Films and Multilayers
[PROP]:FeMgO, FeAlO, insulating granular system, tunnel-type GMR, Hall effect
******************************************************************************
[ID ]:KL97-296
[AUTH]:Ohba Masashi, Takanashi Koki and Fujimori Hiroyasu
[TITL]:Indirect Exchange Coupling and Magnetization Processes in Co/X/Gd/X
Multilayers (X=Cu, Ag, Au, Pt, Y, and W) (in Japanese)
[SOUR]:Nippon Oyo Jiki Gakkaishi (J. Magn. Soc. Jpn.), 21[4-2] (1997), 537-540
[LAB ]:(3); Fujimori
[ABST]:We investigated the indirect exchange coupling between Co and Gd across
nonmagnetic interlayers in Co/X/Gd/X multilayers (X=Cu, Ag, Au, Pt, Y,
and W). The spin-flop field, H[sf], decrease with increasing interlayer
thickness, t[X], for all X. However, the manner of the decrease depends
strongly on X: For X=Cu, H[sf] decreases owing to interdiffusion
between Cu and Cu and Gd at the interfaces. For-X=Ag, Au, Pt, Y, and W,
the decrease in H[sf] is considered to be due to a decrease in the
exchange coupling strength, J[Co-Gd]. For X=Ag, Au, Pt, and Y, J[Co-Gd]
decreases slowly with increasing t[X] and remains even for t[X] geq 10
angstrom; for X=W, on the other hand, it decreases repidly and
disappears for t[X] geq 5 angstrom. We consider that the difference is
attributable to the electronic structure of X.
[TYPE]:Thin Films and Multilayers
[PROP]:Co/Gd multilayers, interlayers, spin-flop, indirect exchange coupling
******************************************************************************
[ID ]:KL97-297
[AUTH]:Watazu Akira, Masumoto Hiroshi, Masuda Yoichiro and Hirai Toshio
[TITL]:Optical Properties of C-Axis Oriented Ba[2]NaNb[5]O[15] Thin Films
Formed by Electron Cyclotron Resonance Plasma Sputtering (in Japanese)
[SOUR]:Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi (J. Ceram. Soc. Jpn.),
105[8] (1997), 687-689
[LAB ]:(1); Hirai; Hachinohe Inst. of Technol.
[ABST]:Thin films of Ba[2]NaNb[5]O[15] (BNN) with (001) orientation were
formed on sapphire (0001) substrates by electron cyclotron resonance
plasma sputtering using ring shaped targets. The thin films were
obtained at a substrate temperature of 773K using a target of Ba : Na :
Nb=1.2 : 1.2 : 5.0 composition. The surface of BNN thin films was flat.
The thickness of BNN thin films was estimated to be 7.2mu m. The
absorption edge of BNN films was about 310nm. The transmittance in the
wavelength between 400 and 2500nm was more than 75%. The refractive
index of the film was estimated to be 2.25-2.34 at 1100 to 2500nm.
[TYPE]:Thin Films and Multilayers
[PROP]:electron cyclotron resonance plasma sputtering, Ba[2]NaNb[5]O[15], thin
film, transmittance, refractive index
******************************************************************************
[ID ]:KL97-298
[AUTH]:Watazu Akira, Masumoto Hiroshi, Masuda Yoichiro, Baba Akira, Goto
Takashi and Hirai Toshio
[TITL]:Preparation of Ba[2]NaNb[5]O[15] Thin Films by Electron Cyclotron
Resonance Plasma Sputter Method and Their Properties (in Japanese)
[SOUR]:Funtai oyobi Funmatsu Yakin (J. Jpn. Soc. Powder Powder Metall.), 44
(1997), 86-89
[LAB ]:(1); Hirai; Hachinohe Inst. of Technol.
[ABST]:Ba-Na-Nb-O thin films were formed on sapphire (1 1 -2 0) substrates by
electron cyclotron resonance plasma sputtering by using ring shaped
targets. A Ba[2]NaNb[5]O[15](BNN) thin film of single phase was
obtained at the substrate temperature of 873K by using the target
composition of Ba : Na : Nb=1.0 : 1.0 : 5.0. The (001) oriented BNN
film was successfully obtained at 923K. The contents of Ba and Nb in
the films were independent of substrate temperature in the range
between 298K and 923K. However, Na content decreased with increasing
substrate temperature. Deposition rates of the BNN thin films were
estimated to be about 1.0 times 10]-1[ nm/s. The absorption edge of the
BNN films deposited at 923K became clear in the vicinity of 300nm. The
transmittance in the wavelength between 700 and 2000nm have exceedingly
by more than 80%. The refractive index of the film was estimated about
2.07 at 927nm.
[TYPE]:Thin Films and Multilayers
[PROP]:electron cyclotron resonance plasma sputtering, Ba[2]NaNb[5]O[15], thin
film, transmittance, refractive index
******************************************************************************
[ID ]:KL97-299
[AUTH]:Belosludov Rodion Vladimirovich, Li Zhi Qiang and Kawazoe Yoshiyuki
[TITL]:Theoretical Study of Structures, Energetics, and Electronic Properties
of Small Urea Clusters by AB INITIO Calculations
[SOUR]:J. Inorg. Biochem., 67[4] (1997), 453
[LAB ]:(3); Kawazoe
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:urea cluster, dimer, trimer, electron density, IR spectrum
******************************************************************************
[ID ]:KL97-300
[AUTH]:Chen Hao, Shi Yaoming, Yu Jing Zhi, Zhu Jia Lin and Kawazoe Yoshiyuki
[TITL]:Phonon-Associated Conductance through a Quantum Point Contact
[SOUR]:Phys. Rev. B, 55[15] (1997), 9935-9940
[LAB ]:(2); Dept. of Phys., Fudan Univ.; Dept. of Phys., Shanghai Univ.;
Kawazoe
[ABST]:By using an independent-boson model we study the electronic conductance
through a quantum point contact in the presence of the electron-phonon
interaction. We find that the phonon energy plays a crucial role in the
quantum behavior of the conductance.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:independent Boson model, electron-phonon interaction, quantum
transport, temperature dependence
******************************************************************************
[ID ]:KL97-301
[AUTH]:Chen Hao, Wu Jian, Li Zhi Qiang and Kawazoe Yoshiyuki
[TITL]:Correlated Conductance through a Lattice of Quantum Dots: Metal to
Antiferromagnetic Insulator Transition
[SOUR]:Phys. Rev. B, 55[3] (1997), 1578-1581
[LAB ]:(2); Dept. of Phys., Fudan Univ.; Dept. of Phys., Tsinghua Univ.;
Kawazoe
[ABST]:The recursive Green's function and temperature Kubo formula are used to
investigate the conductance quantization and the behavior of resonant
tunneling through a finite lattice of quantum dots at low temperatures.
A metal to antiferromagnetic insulator transition, which is driven by
strong Hubbard interaction, is found around the half filling in the
quantum dot lattice. Our numerical results explain that the
Mott-insulator state is caused by the antiferromagnetic spin density
wave.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:temperature Kubo formula, Green's function, Hubbard interaction,
Mott-insulator, resonant tunneling
******************************************************************************
[ID ]:KL97-302
[AUTH]:El-Eskandarany M.S
[TITL]:Consolidation of Ball-Milled (Al-TM)-SiC(TM; Ti, Mo and Cu) Composite
Powders by Plasma Activated
[SOUR]:Funtai oyobi Funmatsu Yakin (J. Jpn. Soc. Powder Powder Metall.),
44[12] (1997), 1143-1147
[LAB ]:(2); Al-Azhar Univ.; Hirai; Ken-Fujimori
[ABST]:Elemental powders of Al(79vol.%), TM(TM; Ti, Mo and Cu)(1vol.%) and
beta-SiC(20vol.%) compound were mechanically alloyed using ball-milled
technique. The end-product which is a composite Al-SiC-TM
nanocrystalline powders was consolidated into compact (20mm in
diameter) using the plasma activated sintering method. The as-milled
and as consolidated samples were characterized by means of X-ray
diffraction, transmission electron microscopy, scanning electron
microscopy and chemical analysis. Moreover, the hardness of the
compacted sample was determined using a Vickers indenter with a load of
10kg, and found to be 2.27GPa. In addition, the density of the
consolidated sample was determined by Archimedes' principle using water
immersion and found to be 3x10]3[ kg.m]-3[. The effect of the TM
elements on the mechanical properties (Poisson's ratio, Young's modulus
and shear modulus) of Al-SiC bulk composite has been studied.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:aluminium-transition metal, silicon-carbide, mechanical alloying, ball
milling, nanocrystalline composite, plasma sintering
******************************************************************************
[ID ]:KL97-303
[AUTH]:Esfarjani Keivan, Hashi Yuichi, Itoh Satoshi, Ihara Shigeo and Kawazoe
Yoshiyuki
[TITL]:Stability and Vibrational Spectra of Toroidal Isomers of C[240]
[SOUR]:Z. Phys. D, 41 (1997), 73-76
[LAB ]:(2); Kawazoe; Hitachi Tohoku Software Ltd.
[ABST]:To study the thermodynamic and mechanical stability of toroidal isomers
of C[240], we use a semi-empirical tight-binding theory and calculate
their electronic structure, cohesive energy and vibrational spectra
within the harmonic approximation. From these, we deduce their free
energy at temperatures up to 1500K. The results are also compared to
the isomer with icosahedral symmetry. Finally, we discuss within this
approach, their stability and abundance.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:C[240] isomer, tight binding model, harmonic approximation
******************************************************************************
[ID ]:KL97-304
[AUTH]:Hihara Takehiko, Sumiyama Kenji, Sakurai Masaki, Onodera Hideya, Wakoh
Kimio and Suzuki Kenji
[TITL]:Anomalous Concentration Dependence of GMR in Fe/Cu Granular Films
Prepared by Cluster Beam Deposition
[SOUR]:J. Phys. Soc. Jpn., 66[5] (1997), 1450-1456
[LAB ]:(1); Suzuki; Yamayasu; Gijutsu
[ABST]:Fe cluster dispersed Fe[X]Cu[100-X] granular films have been produced
by a cluster beam (CB) technique. X-ray diffraction and XAFS
measurements indicate that the structure of Fe clusters is b.c.c. for
x]60, f.c.c. for x[20 and b.c.c. + f.c.c. for 20[x[60.
Magnetoresistance (MR) does not saturate even at an external field of
140kOe, probably because Fe clusters are very small and magnetic
moments of Fe atoms at the cluster surface display a spin glass and/or
superparamagnetic character. The MR value monotonically increases with
decreasing Fe concentration, showing no maximum. Based upon the
Mossbauer spectra, spontaneous magnetic moments and structural studies,
such anomalous concentration dependence of MR is attributed to the
characteristic magnetism of the present Fe[X]Cu[100-X] granular films:
Fe clusters are spin glass in the dilute Fe-f.c.c., antiferromagnetic
in the Cu-rich f.c.c. and ferromagnetic in the Fe-rich b.c.c. region.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:iron-copper, granular material, magnetoresistance, x-ray absorption
fine structure, Mossbauer effect
******************************************************************************
[ID ]:KL97-305
[AUTH]:Hihara Takehiko, Xu Yingfan, Konno Toyohiko J, Sumiyama Kenji, Onodera
Hideya, Wakoh Kimio and Suzuki Kenji
[TITL]:Microstructure and Giant Magnetoresistance in Fe-Cu Thin Films Prepared
by Cluster-Beam Deposition
[SOUR]:Jpn. J. Appl. Phys., 36[6A] (1997), 3485-3491
[LAB ]:(1); Suzuki; Yamayasu; Gijutsu
[ABST]:Giant magnetoresistive Fe[x]Cu[100-x] granular thin films have been
prepared by cluster-beam deposition. The magnetoresistance (MR) ratio
of the as-deposited films decreases monotonically with increasing Fe
content. High resolution transmission electron microscopy of a low Fe
content (x=12) sample shows chemically-homogeneous, fine grains having
a fcc structure. The film with x=28 exhibits, however, distinct
chemical heterogeneity, where bcc Fe clusters are formed in the Cu
matrix. The film with a higher Fe content (x=53) consists mostly of the
bcc phase with a small amount of the fcc phase. Mossbauer spectroscopy
indicated that this MR behavior can be ascribed to the change in the
magnetic state of Fe clusters with increasing the Fe content of the
films: from cluster-glass to antiferromagnetic, and then to
ferromagnetic states. After annealing, phase separation occurs in all
specimens, and the grain size increases markedly, resulting in the
suppression of the MR ratio in the low Fe content region.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:iron-copper, granular metarial, cluster beam deposition, high
resolution, transmission electron microscopy, giant magnetoresistance
******************************************************************************
[ID ]:KL97-306
[AUTH]:Inoue Akihisa and Kimura Hisa Michi
[TITL]:High-Strength Al-Based Alloys Consisting Mainly of Nanoscale
Quasicrystalline or Amorphous Particles
[SOUR]:Mater. Sci. Forum, 235-238 (1997), 873-880
[LAB ]:(2); Inoue; LDRAM
[ABST]:This review deals with the microstructure and mechanical properties of
Al-based nano-quasicrystalline(Q) and nano-amorphous(A) alloys obtained
by rapid solidification. The nano-Q alloys are composed of
icosahedral(I) particles with a size of 30nm surrounded by an Al layer
with a thickness of 10nm for the Al-Cr-Ce and Al-Mn-Ce base alloys and
the volume fraction of the I-phase is about 70%. The nano-Q alloys
exhibit high tensile strength (sigma[f]) of 1350MPa for the
Al[94.5]Cr[3]Ce[1]Co[1.5] alloy and the I particles have a short-range
disorder and long-range I structure. The bulk I-based alloys produced
by extrusion of I-based powders have sigma[f] of 500 to 850MPa and
elongations of 6 to 25%. The nano-A alloys consist of granular
amorphous and Al phases with sizes of about 10 and 7nm, respectively,
for the Al-V-Fe alloys. The formation of the nanogranular A-phase is
presumably due to the suppression of the transition from supercooled
liquid to I-phase. The sigma[f] reaches 1390MPa for the Al[94]V[4]Fe[2]
alloy and decreases by the transition to I+Al phases. These properties
are excellent enough to demonstrate the validness of the structure
control to nano-Q and nano-A phases.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:aluminum base alloy, nanoscale quasicrystalline phase, nanoqranular
amorphous phase, high tensile strength, rapid solidification
******************************************************************************
[ID ]:KL97-307
[AUTH]:Inoue Akihisa and Makino Akihiro
[TITL]:Improvement of Soft Magnetic Properties of Nanocrystalline Fe-M-B (M=Zr
and Nb) Alloys and Their Applications
[SOUR]:Nanostruct. Mater., 9 (1997), 403-412
[LAB ]:(2); Inoue; Central Res. Lab., Alps Electric Co. Ltd.
[ABST]:With the aim of developing good soft magnetic materials, we examined
the magnetic properties of nanocrystalline Fe-M-B alloys containing
various additional elements. The nanoscale bcc Fe-Zr-Nb-B-Cu alloys
exhibited excellent soft magnetic characteristics of 1.5 to 1.6T for
saturation magnetization (B[s]), 1 to 2A/m for coercive force (H[c]),
10x10]4[ to 12x10]4[ for permeability (mu[e]) at 1 kHz and nearly zero
saturated magnetostriction (lambda[s]) which had not been achieved for
soft magnetic materials reported up to date. The excellent soft
magnetic characteristics have already enabled the practical use as
pulse transformers for portable telephones which require high mu[e]
above 10]5[ at 1 kHz and high B[s] above 1.5T. The application fields
are hereafter expected to increase significantly because of the
excellent soft magnetic properties which have been obtained only for
the present materials.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:nanocrystalline alloy, soft magnetic property, nanocrystallization,
Fe-based alloy, pulse transformer
******************************************************************************
[ID ]:KL97-308
[AUTH]:Ishihara Masahito, Chen Hao, Li Zhi Qiang and Kawazoe Yoshiyuki
[TITL]:Magnetoconductance Fluctuations in a Mesoscopic Quantum Ring
[SOUR]:Nonlinear Opt., 18[2-4] (1997), 193-196
[LAB ]:(2); Kawazoe; Dept. of Phys., Fudan Univ.
[ABST]:The effect of electron-electron Hubbard interaction on
magnetoconductance fluctuations in disordered quantum ring is studied
by using a recursive real-space Green's function technique in
tight-binding model. The present numerical results improve previous
theoretical results for the magnetoconductance fluctuations as a
function of magnetic flux compared with experiments. Several new
anomalous phenomena at low temperatures, which do not survive at high
temperatures, are obtained.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:magnetoconductance, quantum ring
******************************************************************************
[ID ]:KL97-309
[AUTH]:Kasukabe Yoshitaka, Takeda Shuuhei, Fujino Yutaka, Yamada Yukio, Nagata
Shinji, Kishimoto Mokuyoshi and Yamaguchi Sadae
[TITL]:Early Nitriding Stage of Evaporated-Ti Thin Films by N-Ion Implantation
[SOUR]:J. Vac. Sci. Technol., A, 15[4] (1997), 1848-1852
[LAB ]:(1); Dept. of Nuclear Eng., Faculty of Eng., Tohoku Univ.; Yamasada
[ABST]:The early growth stage of epitaxial titanium nitride (TiN) films,
formed by implanting nitrogen ions N[2]]+[ with 62keV into 100-nm-thick
evaporated-Ti films, was studied by transmission electron microscopy,
Rutherford backscattering spectrometry and elastic recoil detection
analysis. Evaporated-Ti films spontaneously absorb hydrogen (H) from
the interior of the NaCl substrate, and then TiH[x] partially grows in
addition to the hcp-Ti. The implantation of N into evaporated-Ti films
expands the hcp-Ti lattice and reduces the H concentration in the
evaporated-Ti film. The former induces the hcp-fcc transformation and
then leads to the growth of (001)-oriented TiN[y] by the occupation of
N in octahedral (O) sites in the fcc-Ti sublattice. The latter induces
contraction of the fcc-Ti sublattice by the escape of H from
(110)-oriented TiH[x] and then leads to the growth of (110)-oriented
TiN[y] by the occupation in O sites of the H-escaped metastable fcc-Ti
lattice by N. The nitriding mechanism of epitaxial Ti thin films is
discussed.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:Ti film, N-implantation, titanium nitride film
******************************************************************************
[ID ]:KL97-310
[AUTH]:Kasuya Atsuo, Sasaki Yoshiro, Saito Yahachi, Tohji Kazuyuki and Nishina
Yuichiro
[TITL]:Evidence for Size-Dependent Discrete Dispersions in Single-Wall
Nanotubes
[SOUR]:Phys. Rev. Lett., 78[23] (1997), 4434-4437
[LAB ]:(2); DRAM; Dept. of Basic Sci. Ishinomaki Senshu Univ.; Dept. of
Electrical and Electronic Eng. Mie Univ.; Dept. of Geoscience and
Technol. Tohoku Univ.
[ABST]:Raman scattering spectra of single-wall nanotubes with mean radii 0.55,
0.65, and 1.0nm show size-dependent multiple splittings of the optical
phonon peak corresponding to the E[2g] mode in graphite. These
splittings constitute the first experimental evidence for the unique
feature of nanotubes that they exhibit discrete and diameter-dependent
dispersions arising from their cylindrical symmetry. The observed
dispersion is well explained on the basis of graphite, and shows
possibilities of predicting and controlling the basic property of
nanotubes in the zone-folding scheme.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:nanotube, size effect, phonon dispersion
******************************************************************************
[ID ]:KL97-311
[AUTH]:Kawamura Yoshihito, Liu Hong Bin, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Rapidly Solidified Powder Metallurgy Al-Ti-Fe Alloys
[SOUR]:Scr. Mater., 37[2] (1997), 205-210
[LAB ]:(2); Inoue; Masumoto
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:Al-Ti-Fe, rapid solidification, powder metallurgy, extrusion,
mechanical property
******************************************************************************
[ID ]:KL97-312
[AUTH]:Kim Hyun Goo, Myung Wha Nam, Sumiyama Kenji and Suzuki Kenji
[TITL]:Formation and Chemical Leaching of Rod-Milled Al(Ni-Fe) Alloy
[SOUR]:J. Korean Phys. Soc., 31[1] (1997), 189-192
[LAB ]:(1); Chosun Univ.; Chonnam National Univ.; Ken-Fujimori
[ABST]:We report the formation and the chemical leaching of nanocrystalline
Al[0.6](Ni[75]Fe[25])[0.4] powders by rod milling. An X-ray
diffractometer, a transmission electron microscope, a differential
scanning calorimeter, a Mossbauer spectroscope, and a vibrating sample
magnetometer were utilized to characterize the as-milled and leached
specimens. The crystallite size and the saturation magnetization
decreased with milling time and reached values of 4.4nm and 2.6emu/g,
respectively, after 600h of milling. The rod-milled alloy powders
retained their bcc structure after being treated at room temperature
and at 85Ž with a 25-wt% KOH solution. The leached powders were
transformed to a ferromagnetic fcc phase at high temperature. On
cooling of the specimen from 750Ž, the spontaneous magnetization, M,
sharply increased at about 550Ž, indicating that the bcc phase was
transformed to an fcc phase. The M at room temperature was about
49emu/g.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:aluminium-nickel-iron, mechanical milling, chemical leaching,
magnetization
******************************************************************************
[ID ]:KL97-313
[AUTH]:Kim Hyun Goo, Sumiyama Kenji and Suzuki Kenji
[TITL]:Metastable bcc Ni Produced by Rod Milling and Chemical Leaching
[SOUR]:J. Alloys Compd., 260 (1997), 23-27
[LAB ]:(1); Chosun Univ.; Ken-Fujimori
[ABST]:Nanocrystalline Al[60]Ni[40] and Ni have been obtained by rod milling
Al and Ni powder mixtures and chemical leaching Al atoms from the
rod-milled Al[60]Ni[40], respectively. The rod-milled alloy powders
retained their bcc structure after being treated at room temperature
and at 85Ž with a 25-30wt.% KOH solution. The leached powders are very
active and easily explode when they come into contact with air. The
leached powders were transformed to a ferromagnetic fcc phase at high
temperature. On cooling of the specimen from 600Ž, spontaneous
magnetization M sharply increased at about 350Ž, indicating that the
bcc phase was transformed to an fcc phase. It has been confirmed that
the leaching temperature and annealing temperature and KOH
concentration have a considerable effect on structural and magnetic
properties.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:rod-milling, Al-Ni, chemical leaching, metastable phase, transmission
electron microscope
******************************************************************************
[ID ]:KL97-314
[AUTH]:Knobel M., Chiriac Horia, Sinnecker J.P, Marinescu S., Ovari T.A
[TITL]:Comparative Study of the Giant Magneto-Impedance Effect in Fe-Based
Nanocrystalline Ribbons
[SOUR]:Sens. Actuators A, 59[1-3] (1997), 256-260
[LAB ]:(2); IFGW UNICAMP; Inst. of Technical Phys., Romania; Inoue
[ABST]:We report the results of our studies on the giant magneto-impedance
effect in nanocrystalline Fe[73.5]Cu[1]Nb[3]Si[13.5]B[9],
Fe[90]Hf[7]B[3], and Fe[90]Zr[7]B[3] ribbons. The results are explained
by taking into account the basic magnetic and electrical properties,
and also the domain structures from these ribbons. Our analysis is
important from the practical point of view due to the immediate
application possibilities offered by the giant magneto-impedance
effect.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:nanocrystalline magnetic materials, giant magneto-impedance effect,
magnetic sensors
******************************************************************************
[ID ]:KL97-315
[AUTH]:Kojima Akinori, Makino Akihiro and Inoue Akihisa
[TITL]:Structural and Magnetic Properties of Nanocrystalline Fe-Rich
Fe-Nb-Nd-B Sintered Magnets Produced by Consolidating Amorphous Powders
[SOUR]:IEEE Trans. Magn., 33[5] (1997), 3817-3819
[LAB ]:(2); Faculty of Eng., Tohoku Univ.; Alps Electric Co., Ltd.; Inoue
[ABST]:Nanocrystalline bulk Fe[88]Nb[2]Nd[5]B[5] and Fe[86]Nb[2]Nd[7]B[5]
alloys were made by consolidating amorphous powders with an
electric-pulse-current-sintering method and subsequent annealing. Bulk
alloy made by consolidating amorphous powders has a higher density (the
maximum density could reach 7.5g/cm]3[ consolidating at 873K and
636MPa) than that made by consolidating crystalline powders, presumably
because the amorphous alloy softens around the crystallization
temperature. The structure formed after annealing at 1023K for 180s
shows a nanocrystalline composite consisting of bcc-Fe, Nd[2]Fe[14]B
and Fe[3]B or Fe[2]B phases with grain sizes of 20-40nm The
nanocrystalline bulk Fe[88]Nb[2]Nd[5]B[5] alloy shows hard magnetic
properties, remanence (J[r]) of 1.05T, coercive force (H[J]) of
263kA/m, and maximum energy product ((BH)[max]) of 75kJ/m]3[.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:nanostructure alloy, Fe-Nb-Nd-B system, hand magnetic
******************************************************************************
[ID ]:KL97-316
[AUTH]:Lee Tae Haeng, Kawamura Yoshihito, Inoue Akihisa, Cho Seong Seock and
Masumoto Tsuyoshi
[TITL]:Mechanical Properties of Rapidly Solidified Al-Si-Ni-Ce P/M Alloys
[SOUR]:Scr. Mater., 36[4] (1997), 475-480
[LAB ]:(2); Cheonan National Junior Technical College; Inoue; Chungnam
National Univ.; Res. Inst. for Electric and Magn. Mater.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:Al-Si-Ni-Ce, rapidly solidification, powder metallurgy, mechanical
properties
******************************************************************************
[ID ]:KL97-317
[AUTH]:Li Zhi Qiang, Hashi Yuichi and Kawazoe Yoshiyuki
[TITL]:Magnetic Properties of Nanoscale Fe Clusters in Cu
[SOUR]:J. Magn. Magn. Mater., 167[1&2] (1997), 123-128
[LAB ]:(2); Hitachi Tohoku Software Ltd., Res. for Develop. Center.; Kawazoe
[ABST]:The magnetic and electronic properties of fcc Fe clusters embedded in a
Cu matrix are studied by the first-principles spin-polarized
calculations within the local density functional formalism. A single Fe
atom in a Cu host is found to have a magnetic moment of 3.05mu[B].
Small Fe[n] clusters (leq13) in Cu exhibit high-moment ferromagnetic
coupling, while larger clusters (geq13) in Cu show low-moment
antiferromagnetic coupling. The magnetic properties of embedded fcc Fe
clusters in Cu have some features in common with nanoscale fcc
Fe/Cu(100) films.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:Fe cluster in Cu, ferromagnetism, antiferromagnetism, DVM(discrete
variational method)
******************************************************************************
[ID ]:KL97-318
[AUTH]:Lu Rong, Zhu Jia Lin, Chen Xi, Chang Lee and Kawazoe Yoshiyuki
[TITL]:Macroscopic Magnetization Tunneling and Coherence in Antiferromagnetic
Particles
[SOUR]:Phys. Lett. A, 226[1,2] (1997), 112-116
[LAB ]:(2); Dept. of Phys., Tsinghua Univ. China; CCAST(World Lab.); Kawazoe
[ABST]:We systematically investigate the macroscopic quantum effects of
antiferromagnetic particles for three different forms of the magnetic
anisotropy and the external magnetic field employing the method of two
sublattices. The tunneling rates are obtained in each case with the
help of the instanton method. The effect of the topological term is
also studied.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:magnetic anisotropy, instanton, Neel vector, exchange energy, path
integral
******************************************************************************
[ID ]:KL97-319
[AUTH]:Makino Akihiro, Hatanai Takashi, Naitoh Yutaka, Bitoh Teruo, Inoue
Akihisa and Masumoto Tsuyoshi
[TITL]:Applications of Nanocrystalline Soft Magnetic Fe-M-B(M=Zr, Nb) Alloys
"NANOPERM"
[SOUR]:IEEE Trans. Magn., 33[5] (1997), 3793-3798
[LAB ]:(2); Alps Electric Co., Ltd.; Inoue
[ABST]:This paper reviews our recent results on some applications of new
nanocrystalline soft magnetic Fe-M-B (M=Zr, Hf, Nb) alloy ribbons
"NANOPERM". NANOPERM has a structure consisting of nanoscale bcc grains
and a small amount of an intergranular amorphous layer. NANOPERM
exhibits high saturation magnetic flux density above 1.5T as well as
excellent soft magnetic properties. Furthermore, its remanence ratio
can be controlled according to the demands of various applications.
Toroidal cores with gap, common mode choke coils, ISDN (integrated
service digital network) interface pulse transformers and flux gate
magnetic detectors made of "NANOPERM" have been developed. The
excellent characteristics of the components were confirmed in trial.
NANOPERM is therefore expected to be used widely in the magnetic
application field.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:nanocrystalline alloy, nanoperm, soft magnetic property amorphous
phase, nanocrystallization
******************************************************************************
[ID ]:KL97-320
[AUTH]:Matsuura Makoto, Sakurai Masaki, Suzuki Kenji, Adachi Hiromichi and Ino
Hiromitsu
[TITL]:Amorphous Fe Clusters Imbedded in fcc La for Melt-Quenched La-Fe Alloys
[SOUR]:J. Phys. IV, 7[C2] (1997), 1015-1016
[LAB ]:(2); Miyagi National College of Technol.; Suzuki; Faculty of Eng.,
Univ. of Tokyo
[ABST]:Fluorescence XAFS measurements of the Fe K-edge are done for
melt-quenched La-rich La-Fe alloys. XAFS results of the as-quenched
samples of La[92]Fe[8] and La[88]Fe[12] show characteristic features of
disordered structure. The results for La[88]Fe[12] after annealed at
400Ž for 30 min. show that Fe are precipitated to alpha-Fe in beta-La.
A strange phenomenon of finding the amorphous clusters in the
crystalline phase can be attributed to the immiscible nature and large
atomic size difference between Fe and La.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:La-Fe, EXAFS, amorphous Fe cluster, nano cluster, local structure
******************************************************************************
[ID ]:KL97-321
[AUTH]:Matsuura Makoto, Sakurai Masaki, Suzuki Kenji, Tsai An Pan and Inoue
Akihisa
[TITL]:Local Structure Change of Ce and Cu in the Course of Nanocrystalline
Formation from Amorphous Al[87]Ni[8]Ce[3]Cu[2]
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 511-514
[LAB ]:(2); Miyagi National College of Technol.; Suzuki; Inoue
[ABST]:Local structures of Ni in Al[87]Ni[10]Ce[3] and Al[85]Ni[10]Ce[5] and
Cu in Al[87]Ni[8]Ce[3]Cu[2] are studied by means of XAFS measurements
in order to know the role of small additives in the formation of
nanocrystalline alpha-Al from amorphous matrix. Local structures of Ni
in Al[87]Ni[10]Ce[3] and Cu in Al[87]Ni[8]Ce[3]Cu[2] show very small
changes after annealing just after the alpha-Al nanocrystalline
formation, which indicates both Ni and Cu are excluded from
precipitated alpha-Al like Ce in Al[87]Ni[10]Ce[3]. Local structure of
Cu for the as-quenched state is different from that of Ce and Ni;
nearest neighbors of Cu consist of Cu rich atoms, while those for Ce
and Ni consists mostly of Al rich. Small amount of Cu addition induces
segregation of Cu rich region and increases inhomogeneity of the
matrix.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:Al[87]Ni[8]Ce[3]Cu[2], EXAFS, amorphous, nanocrystalline, local
structure
******************************************************************************
[ID ]:KL97-322
[AUTH]:Naitoh Yutaka, Bitoh Teruo, Hatanai Takashi, Makino Akihiro, Inoue
Akihisa and Masumoto Tsuyoshi
[TITL]:Development of Common Mode Choke Coil Made of New Nanocrystalline Soft
Magnetic Alloy "KNANOPERM"
[SOUR]:Sci. Rep. RITU, A43[2] (1997), 161-165
[LAB ]:(2); Central Res. Lab., Alps Electric Co. Ltd.; Inoue; The Res. Inst.
of Electrical and Magnetic Mater.
[ABST]:We have developed the common mode choke coils made of a kind of new
nanocrystalline soft magnetic Fe-M-B (M=Zr, Nb, Hf) based alloys,
"NANOPERM", with high saturation magnetic flux density above 1.5T as
well as excellent soft magnetic properties. The very low remanence
ratio, which is necessary to obtain good pulse voltage attenuation
characteristics of the common mode choke coils, has been obtained by
annealing treatment in a static transverse magnetic field. Insertion
loss and the pulse voltage attenuation characteristics of the NANOPERM
common mode choke coil have been found to be superior to those of the
choke coil made of MnZn-ferrite. Furthermore, the NANOPERM common mode
choke coil exhibits stable inductance characteristics against
temperature change. It can be concluded that NANOPERM is suitable for a
core material of the common mode choke coils.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:nanocrystalline soft magnetic alloy, common mode choke coils, insertion
loss, pulse voltage attenuation, magnetic field induced anisotropy
******************************************************************************
[ID ]:KL97-323
[AUTH]:Ohno Kaoru, Li Zhi Qiang, Kamiyama Hiroshi, Kawazoe Yoshiyuki, Xue Q,
Hashizume Tomihiro, Hasegawa Yukio, Shinohara Hisanori and Sakurai
Toshio
[TITL]:A Mechanism of 13% Lattice Expansion in C[60] FCC(110) Thin Films Grown
on the GaAs(001) As-rich Surface
[SOUR]:Sci. Rep. RITU, A43[1] (1997), 61-65
[LAB ]:(2); Kawazoe; Aomori Public College; Sakurai; Adv. Res. Lab., Hitachi
Ltd.; Chem. Dept., Nagoya Univ.
[ABST]:We perform a classical molecular dynamics simulation, a first-principle
calculation based on LDA, and moreover a simple theoretical analysis to
examine the very interesting crystallographic structure of the first
layer and overlayer C[60]s adsorbed on the As-rich substrate of the
GaAs(001) surface, which was recently observed with the STM by our
group. From the classical molecular dynamics study, we reproduce the
pairwise structure of C[60] adsorbed in the first layer. On the other
hand, from the first-principle study, we estimate how much the charge
transfer is from the underlayer As atoms to the C[60]s adsorbed in the
first layer. We found that the amount of this charge transfer is large
enough to expect that the strong dipole field caused by this dipole
layer at the interface induces dipole moments in the C[60]s adsorbed on
overlayers and that the resulting dipole-dipole interaction among the
overlayer C[60] molecules is the origin of the 13% lattice expansion of
the overlayer C[60] fcc thin film observed experimentally.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:C[60], GaAs, surface adsorption, lattice expansion
******************************************************************************
[ID ]:KL97-324
[AUTH]:Sakuma Hiroko, Tachibana Masaru, Sugiura Hiroshi, Kojima Kenichi, Ito
Shun, Sekiguchi Takashi and Achiba Yohji
[TITL]:Growth and Structures of C[60] Shells
[SOUR]:J. Mater. Res., 12[6] (1997), 1545-1550
[LAB ]:(1); Yokohama City Univ.; Gijutsu; Suezawa; Tokyo Metropolitan Univ.
[ABST]:The growth of the shells of C[60] crystals was carried out under
various conditions. The detailed structures of the grown shells were
investigated by transmission electron microscopy and Raman
spectroscopy. The shells were formed during thermal sublimation of the
C[60] crystals, which were irradiated with white light in air. The
shells were mainly composed of a kind of amorphous carbon. From these
results, it is suggested that the oxygen-induced disintegration of
C[60] cages is responsible for the shell formation.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:C[60], shell, TEM, Raman
******************************************************************************
[ID ]:KL97-325
[AUTH]:Sakurai Junji, Huo Dexuan, Kuwai Tomohiko, Mori Katsunori, Hihara
Takehiko, Sumiyama Kenji and Suzuki Kenji
[TITL]:The Sign of Magneto-Thermoelectric Power of Magnetic Granular Alloys
[SOUR]:J. Phys. Soc. Jpn., 66[8] (1997), 2240-2243
[LAB ]:(1); Dept. of Phys., Toyama Univ.; Faculty of Eng., Toyama Univ.;
Suzuki
[ABST]:The thermoelectric power S and magneto-thermoelectric power delta
S=S(H)-S(0) were measured for Fe-Cu and Fe-Ag granular alloys. The sign
of both S and delta S of the measured samples was confirmed to be
negative, similar to that of all the other granular alloys, contrary to
the theories proposed hitherto. We point out the importance of the
Kondo effect of the magnetic impurities between the magnetic and
non-magnetic clusters, and we show we can understand successfully the
sign of both S and delta S from this standpoint.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:Fe-Ag, Fe-Cu, granular film, thermo-electric power, ion-cluster-beam,
sputter-deposition
******************************************************************************
[ID ]:KL97-326
[AUTH]:Sun Qiang, Wang Q.
[TITL]:Local Magnetism of 3d and 4d Impurities in Ag and Pd Clusters
[SOUR]:J. Phys. I, 7[10] (1997), 1233-1244
[LAB ]:(2); Phys. Dept. of South-West Normal Univ., Chongqing; Kawazoe
[ABST]:The local magnetic properties of Ag[12]TM and Pd[12]TM clusters with
I[h] symmetry (TM=Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, Zr, Nb, Mo, Tc, Ru,
Rh, and Pd) have been systematically studied with the density
functional formalism, and the Kohn-Sham equation is solved
self-consistently with the discrete variational method (DVM). A special
attention is paid to the comparisons of local magnetism for impurities
in Ag and Pd clusters with those in the bulk and on the (001) surface
of Ag (Pd), it is found that the behavior of local moments in the
Ag[12] cluster is more complex than the one of a single impurity in
bulk Ag and on the Ag (001) surface, whereas the local moments in
Pd[12] display very similar features as the ones of a single impurity
in bulk Pd and on the Pd (001) surface. In order to better understand
these results, the roles of interactions between impurity and host
atoms on the local moment of impurities are explored: the interactions
of impurity-d with Ag-d orbitals have important contributions to the
local magnetic moments for impurities with less than half-filled d
shell, such as Sc, Ti, V, Y, Zr and Nb, but have minor roles on the
local magnetic moments for impurities Cr, Mn, Fe, Co Ni, Tc, Ru and Rh.
However, in the Pd[12] cluster, d-d interactions between impurity and
host have major roles on all the 3d and 4d impurities. Based on the
interaction point of view, explanations are presented for the
similarities and differences of moment behavior in the cluster, in the
bulk and on the surface. The comparison of the obtained results with
those in the Cu[12] cluster is also made. This study would provide more
comprehensive understandings on the local magnetism of 3d and 4d
impurities in different environments.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:Ag[12]TM, Pd[12]TM, I[h] symmetry, discrete variational method
******************************************************************************
[ID ]:KL97-327
[AUTH]:Suzuki K., Wexler D., Cadogan J.M, Sahajwalla V.
[TITL]:Magnetic Force Microscopy Study of Nanocrystalline Fe[91]Zr[7]B[2] Soft
Magnetic Alloy
[SOUR]:Mater. Sci. Eng., A226-228 (1997), 586-589
[LAB ]:(2); School of Mater. Sci. and Eng., The Univ. of New South Wales;
Dept. of Mater. Eng., Univ. of Wollongong; Inoue
[ABST]:The domain structure of the nanocrystalline Fe[91]Zr[7]B[2] alloy at
the optimum soft magnetic state was studied by means of magnetic force
microscopy (MFM). Curved domains separated by 180‹walls were observed.
The domain wall width (sim pi L[ex], where L[ex] is the exchange
correlation length) was estimated to be less than 2 pm 0.3mu m from the
MFM image. This result is consistent with the L[ex] value (sim 0.5mu m)
evaluated from the measured magnetic properties. These results reveal
that the excellent soft magnetic properties are due to the averaging of
the effects of the magnetocrystalline anisotropy (K[1]) over the order
of 10]4[ grains.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:nanocrystalline soft magnetic alloys, Fe-Zr-B, Exchange correlation
length, magnetic domain structure, magnetic force microscopy
******************************************************************************
[ID ]:KL97-328
[AUTH]:Wang Xiang Dong, Hashizume Tomihiro, Yurov V.
[TITL]:Two-Dimensional Domain Boundary Segregation of C[60] in
Cu(111)4x4-C[60]/C[70] Phase
[SOUR]:Z. Phys. Chem., 202 (1997), S117-125
[LAB ]:(2); Sakurai; Nagoya Univ.; Seoul National Univ.; General Phys. Inst.
of Russia, Russia
[ABST]:The STM study on the C[70]/C[60] adsorption on the Cu(111)1 times 1
surface has shown that C[70]/C[60] forms the 4 times 4 commensurate
reconstruction. A small fraction of solute C[60] introduced to the
C[70] film is found to segregate at domain boundaries (DB) upon
annealing the surface at approximately 350Ž. The segregation is found
to be dependent on the detailed structure of the DB. This phenomenon is
analyzed based on the broken bond model.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:fullerenes, phase transformation, STM
******************************************************************************
[ID ]:KL97-329
[AUTH]:Zhu Jia Lin, Chen Xi and Kawazoe Yoshiyuki
[TITL]:Persistent Currents in a One-Dimensional Disordered Ring in the
Luttinger Model
[SOUR]:Phys. Rev. B, 55[24] (1997), 16300-16305
[LAB ]:(2); Dept. of Phys., Tsinghua Univ.; Kawazoe
[ABST]:The Luttinger model is extended to include disorder effects in ring
geometry. The persistent current in a mesoscopic ring is evaluated
using the concept of topological excitations and path integrals in a
multiply connected system. It is found that the repulsive interaction
counteracts the effect of disorder and enhances the amplitude of the
current. The interplay between interaction and disorder is manifested
clearly in the model calculation.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:one-dimensional disordered Ring, Bogolivbov transformation, Boson mode,
dispersion relation
******************************************************************************
[ID ]:KL97-330
[AUTH]:Zhu Jia Lin, Li Zhi Qiang, Yu Jing Zhi, Ohno Kaoru and Kawazoe
Yoshiyuki
[TITL]:Size and Shape Effects of Quantum Dots on Two-Electron Spectra
[SOUR]:Phys. Rev. B, 55[23] (1997), 15819-15823
[LAB ]:(2); Dept. of Phys., Tsinghua Univ.; Kawazoe
[ABST]:The exact spectra of two electrons confined by two-dimensional and
three-dimensional quantum dots (2D and 3D QD's) with parabolic
potentials are obtained. Using the present results, the size and shape
effects of QD's on the spectra are revealed. It is found that the
spectra are dramatically changed with the variation of the dot size,
and then the crossover of two levels can appear. The variation of
spectra with size and the positions of crossover points are quite
different between 2D and 3D QD's. It is well explained based on the
study of electron-electron interaction energies in 2D and 3D QD's. The
size and shape effects predict a possibility to observe phenomena
related to electron-electron interactions in QD's.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:2D QD, 3D QD, cross over point, electron-electron interaction energy
******************************************************************************
[ID ]:KL97-331
[AUTH]:Zhu Jia Lin, Li Zhi Qiang, Zhu Ziqiang, Kawazoe Yoshiyuki and Yao
Takafumi
[TITL]:Single-Ion, Dot-Size and Dot-Shape Effects on Two Electron Spectra in
Quantum Dots
[SOUR]:Nonlinear Opt., 18[2-4] (1997), 189-192
[LAB ]:(2); Dept. of Phys., Tsinghua Univ.; Kawazoe; Yao
[ABST]:The dot-size and dot-shape effects on electron-electron interactions
and two-electron spectra in two-dimensional and three-dimensional
quantum dots with and without a shallow-donor ion are studied.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:electron spectra, quantumdot
******************************************************************************
[ID ]:KL97-332
[AUTH]:Zhu Jia Lin, Wu Jian, Fu Rong Tang, Chen Hao and Kawazoe Yoshiyuki
[TITL]:Effects of Quantum Size and Potential Shape on the Spectra of an
Electron and a Donor in Quantum Dots
[SOUR]:Phys. Rev. B, 55[3] (1997), 1673-1679
[LAB ]:(2); Dept. of Phys., Tsinghua Univ.; Kawazoe
[ABST]:Spectra of electron and donor states in quantum dots with different
confinement potentials are calculated. The potential-shape,
quantum-size, and donor-position effects on the level ordering and
binding are studied in detail. It is found that a single donor can
heavily change single-electron spectra in the quantum dots with proper
size and potential shape, which may be useful for understanding
physical phenomena and designing materials and devices in quantum-dot
structures.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:level ordering, single electron spectra, confinement potential,
negative donor center, variational calculation
******************************************************************************
[ID ]:KL97-333
[AUTH]:Kojima Akinori, Makino Akihiro and Inoue Akihisa
[TITL]:Nanocrystalline Fe-Nb-Nd-B Sintered Magnets Produced by Consolidating
Amorphous Powders (in Japanese)
[SOUR]:Magnetics kenkyu kai shiryou, Denki Gakkai (Proceeding of Magnetic
Meet., Jpn. Electic Soc.), MAG-97-95 (1997), 13-18
[LAB ]:(2); Alps Electric Co., Ltd.; Inoue
[ABST]:Nanocrystalline bulk Fe[88]Nb[2]Nd[5]B[5] alloy was made by
consolidating amorphous powders with an
electric-pulse-current-sintering method and subsequent annealing. The
bulk alloy made by consolidating amorphous powders has a higher density
than that made by consolidating crystalline powders, presumably because
the amorphous alloy softens around the crystallization temperature. The
structure formed after annealing at 1023 K for 180 s shows a
nanocrystalline composite consisting of bcc-Fe, Nd[2]Fe[14]B and Fe[3]B
or Fe[2]B phases with grain sizes of 20-40nm. The nanocomposite bulk
Fe[88]Nb[2]Nd[5]B[5] alloy with a density of 7.7g/cm]3[ shows hard
magnetic properties, remanence (J[r]) of 1.10T, coercive force (H[cJ])
of 280kA/m, and maximum energy product ((BH)[max]) of 80kJ/m]3[.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:exchange-spring magnets, electric-pulse-current-sintering,
nanocomposite structure, amorphous alloy
******************************************************************************
[ID ]:KL97-334
[AUTH]:Kojima Akinori, Makino Akihiro, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Nanocrystalline Fe-Rich Fe-Nb-Nd-B Magnets Produced by Consolidating
Amorphous Powders (in Japanese)
[SOUR]:Nippon Oyo Jiki Gakkaishi (J. Magn. Soc. Jpn.), 21[4-2] (1997), 365-368
[LAB ]:(2); Alps Electric Co., Ltd.; Inoue; Res. Inst. for Electric and Mater.
[ABST]:Nanocrystalline bulk Fe[88]Nb[2]Nd[5]B[5] and Fe[86]Nb[2]Nd[7]B[5]
alloys were made by consolidating amorphous powders with a
spark-plasma-sintering method and subsequent an nealing. Bulk alloy
made by consolidating amorphous powders has a higher density than that
made by consolidating crystalline powders, presumably because the
amorphous alloy softens around the crystalline temperature. Bulk
Fe[88]Nb[2]Nd[5]B[5] and Fe[86]Nb[2]Nd[7]B[5] alloys made by
consolidating amorphous powders at a temperature of 873K and a pressure
of 636MPa have a density of 7.5g/cm]3[, and form a nanocrystalline
composite structure of bcc-Fe, Fe[3]B, and Nd[2]Fe[14]B phases with
grain sizes of 20-40nm after annealing at 1023K. Nanocrystalline bulk
alloys show hard magnetic properties, remanence (J[r]) of 0.83-1.0T,
coercive force (H[cJ]) of 190-290kA/m, and maximum energy product
(BH)max of 43-49kJ/m]3[.
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:Fe-Nb-Nd-B alloy, nanocrystalline, sintered magnets, high Fe
concentrations, hard magnetic properties
******************************************************************************
[ID ]:KL97-335
[AUTH]:Kojima Akinori, Makino Akihiro and Inoue Akihisa
[TITL]:Production of Nanocrystalline (Fe,Co)-Nb-(Nd,Pr)-B Thin Form Magnets
and Their Magnetic Properties (in Japanese)
[SOUR]:Magnetics kenkyu kai shiryou, Denki Gakkai (Proceeding og Magnetic
Meet., Jpn. Electic Soc.), MAG-97-182 (1997), 65-70
[LAB ]:(2); Graduate School of Eng., Tohoku Univ.; Alps Electric Co., Ltd.;
Inoue
[ABST]:Using the high deformability of amorphous alloy near the
crystallization temperature, bulk alloys with 2-5mm in thickness and
thin form alloys with 300-800mu m in thickness were obtained by
consolidating amorphous Fe[100-x-y]Co[x]Nb[2](Nd,Pr)[y]B[5] (x=0-20,
y=5 and 7) powders. The density of the compacts are 7.5-7.7g/cm]3[ for
the bulk alloys and 7.34-7.48g/cm]3[ for thin form alloys. After
annealing at 973 or 1023K, the consolidated alloys form nanocrystallie
composite structure of soft and hard magnetic phases, show
exchange-spring magnetic properties, and anisotropic magnetic
properties for the alloys with Nd or Pr contents of 7at%. The maximum
energy product ((BH)[max]) measured parallel to the press direction was
found to be 94KJ/m]3[ for Fe[66]Co[20]Nb[2]Pr[7]B[5].
[TYPE]:Fine Particles, Microclusters, Mesoscopic and Nanometer
[PROP]:amorphous, nanocrystalline, consolidation, exchange-spring magnet, thin
form magnets
******************************************************************************
[ID ]:KL97-336
[AUTH]:Fujinaga Yasuo and Syono Yasuhiko
[TITL]:The Cadmium-Zinc Phase Diagram under High Pressure
[SOUR]:High Pressure Res., 15[4] (1997), 233-243
[LAB ]:(2); Syono
[ABST]:Phase relation of the Cd-Zn system at various pressures up to 7.0GPa
was determined by means of isobaric measurement of electrical
resistance and in-situ X-ray diffraction analysis. The eutectic
temperature and melting temperatures of cadmium and zinc increase under
pressure with mean values of the slopes (delta T/delta P)(P=0-7GPa) of
26Ž/GPa, 48Ž/GPa and 38Ž/GPa, respectively. The eutectic composition
moves toward Zn-rich phase from 26.6at% Zn at atmospheric pressure to
58at% Zn at 6.0GPa. The maximum solubility of zinc in the alpha phase
(hcp solid solution on the Cd-rich side) and that of cadmium in the
Beta phase (hcp solid solution on the Zn-rich side) expand slightly
under high pressure. Isobaric temperature-composition sections of the
three-dimensional equilibrium phase diagram of the Cd-Zn system up to
7.0GPa are constructed on the basis of the results.
[TYPE]:Phase Diagram and Transformation
[PROP]:cadmium, zinc, high pressure, phase diagram, melting temperature
******************************************************************************
[ID ]:KL97-337
[AUTH]:Hasegawa Masayuki and Ohno Kaoru
[TITL]:Intermolecular Potentials and Phase Diagrams
[SOUR]:Sci. Rep. RITU, A43[1] (1997), 29-33
[LAB ]:(1); Dept. of Mater. Sci. and Technol., Faculty of Eng., Iwate Univ.;
Kawazoe
[ABST]:A density functional theory of freezing combined with a
thermodynamically consistent integral equation method is used to
investigate the phase behavior of the systems interacting via the m-n
potential with m=2n, phi(r)=4varepsilon[(sigma/r)]2n[-(sigma/r)]n[]
(n=6,8,10 and 12),and the rigid C[60] molecules interacting via the
Girifalco potential. It is found that the liquid-vapour coexisting
region is gradually suppressed as the attractive part of the potential
becomes short-range with increasing n and the coexistence ceases to
occur at n=11. The m-n potential with n=11sim12 is similar to the
Girifalco potential and both yield similar phase diagrams. It is also
found that the phase diagram of C[60] calculated for a truncated
potential is qualitatively in agreement with the corresponding Monte
Carlo (MC) simulations of Hagen et al., which have predicted
nonexistence of the liquid phase in contrast to the molecular dynamics
(MD) simulations of Cheng et al. These results suggest the importance
of treating the long-range tail of the potential correctly and provide
a partial explanation for the discrepancy between the MC and MD
simulations.
[TYPE]:Phase Diagram and Transformation
[PROP]:C[60], intermolecular potential, phase diagram, density functional
theory
******************************************************************************
[ID ]:KL97-338
[AUTH]:Hasegawa Masayuki and Ohno Kaoru
[TITL]:The Dependence of the Phase Diagram on the Range of the Attractive
Intermolecular Forces
[SOUR]:J. Phys.: Condens. Matter, 9[16] (1997), 3361-3370
[LAB ]:(1); Dept. of Mater. Sci. and Technol., Faculty of Eng., Iwate Univ.;
Kawazoe
[ABST]:A density functional theory of freezing combined with a
thermodynamically consistent integral equation method is used to
investigate the phase behavior of systems interacting via the m-n
potential with m=2n, phi(r)=4varepsilon[(sigma/r)]2n[-(sigma/r)]n[]
(n=6,8,10 and 12) and rigid C[60] molecules interacting via the
Girifalco potential. It is found that the liquid-vapour coexistence
region is gradually suppressed as the attractive part of the potential
becomes short range with increasing n and the coexistence ceases to
occur at n approx 11. The m-n potential with n=11-12 is similar to the
Girifalco potential and the two yield similar phase diagrams. It is
also found that the phase diagram of C[60] calculated for a truncated
potential is qualitatively in agreement with the corresponding Monte
Carlo (MC) simulations of Hagen et al, which have predicted
nonexistence of the liquid phase in contrast to the molecular dynamics
(MD) simulations of Cheng et al. These results suggest the importance
of treating the long-range tail of the potential correctly and provide
a partial explanation for the discrepancy between the MC and MD
simulations.
[TYPE]:Phase Diagram and Transformation
[PROP]:C[60], Lennard-Jones potential, intermolecular force, phase diagram,
density functional theory
******************************************************************************
[ID ]:KL97-339
[AUTH]:Parlinski K.
[TITL]:Domain Pattern Formation in Ferroelastic Pb[3](PO[4])[2] by Computer
Simulation
[SOUR]:J. Mater. Res., 12[9] (1997), 2366-2373
[LAB ]:(2); Kawazoe; Inst. of Nucl. Phys.
[ABST]:A model of lead phosphate, which describes the rhombohedral-monoclinic
phase transition is used to form domain patterns in the annealing
process. The obtained domain structures show W and W' types of domain
walls in agreement with the stress-free laws proposed in Sapriel's
theory. The observed W domain walls are parallel to the ternary
symmetry axis, while the W' ones are tilted with respect to the same
axis. The antiphase domain walls take no preferential orientations, and
remain parallel to the ternary axis. The calculated density of the
potential energy of the domain wall of type W is estimated to be
E[dw]=49K/angstrom]2[ at T=300K.
[TYPE]:Phase Diagram and Transformation
[PROP]:Pb[3](PO[4])[2], phase transition, ferroelastic material, soft mode,
molecular dynamics
******************************************************************************
[ID ]:KL97-340
[AUTH]:Parlinski K.
[TITL]:Computer Simulation of Ferroelastic Phase Transition in LaNbO[4]
[SOUR]:J. Mater. Res., 12[9] (1997), 2428-2437
[LAB ]:(2); Inst. of Nucl. Phys.; Hitachi Tohoku Software Ltd.; Fukuda;
Kawazoe
[ABST]:A model of lanthanum orthoniobate which possesses a ferroelastic
tetragonal-monoclinic phase transition is proposed. It contains only
one particle per unit cell, but it is constructed consistently with
symmetry changes at the phase transition. The model parameters are
chosen to reproduce the bare soft mode, degree of deformation of the
tetragonal unit cell to a monoclinic one, and the phase transition
temperature. The ferroelastic system with free boundary conditions was
simulated by the molecular dynamics technique, and the second order
phase transition was reproduced. The studied annealing process shows
formation of the stripe lenticular domain pattern, which has been
interrupted by the appearance of a temporary band of perpendicularly
oriented lenticular domains. The maps contain W'-type domain walls
whose orientations are fixed only by interplay of potential parameters
and not by symmetry elements. The simulated domain pattern has the same
features as those observed by transmission electron microscopy.
[TYPE]:Phase Diagram and Transformation
[PROP]:LaNbO[4], soft mode, phase transition temperature, molecular dynamics,
domain pattern
******************************************************************************
[ID ]:KL97-341
[AUTH]:Parlinski K.
[TITL]:First-Principles Determination of the Soft Mode in Cubic ZrO[2]
[SOUR]:Phys. Rev. Lett., 78[21] (1997), 4063-4066
[LAB ]:(2); Kawazoe; Inst. of Nucl. Phys.
[ABST]:A direct approach to calculate the phonon dispersion using an ab initio
force using constant method is introduced. The phonon dispersion and
structural instability of cubic ZrO[2] are found using a supercell
method in the local-density approximation. The force constants are
determined from the Hellmann-Feynman forces induced by the displacement
of an atom in the 2 times 2 times 2 fcc supercell. This size of the
supercell gives "exact" phonon frequencies at Gamma, X, L, W Brillouin
zone points. The phonon dispersion curves show a pronounced soft mode
at the X point, in agreement with the experimentally observed cubic to
tetragonal phase transition.
[TYPE]:Phase Diagram and Transformation
[PROP]:ZrO[2], ab initio force constant method, local density approximation,
phase transition
******************************************************************************
[ID ]:KL97-342
[AUTH]:Parlinski Krzystof and Kawazoe Yoshiyuki
[TITL]:Ferroelastic Phase Transition in Pb[3](PO[4])[2] Studied by Computer
Simulation
[SOUR]:J. Phys. I, 7 (1997), 153-175
[LAB ]:(3); Kawazoe
[ABST]:A model of lead phosphate which describes its rhombohedral-monoclinic
improper ferroelastic phase transition is proposed. It contains a
reduced number of degrees of freedom but it is constructed consistently
with symmetry changes at the phase transition. Potential parameters of
the model are derived from available experimental data. The
crystallites of 25 times 25 times 25 and 121 times 121 times 25 unit
cells have been simulated by the molecular-dynamics technique. The
results determine the phase transition at the L point of reciprocal
space, the order parameter, and the temperature behavior of monoclinic
lattice parameters. In the rhombohedral phase the calculated dynamical
structure factor shows inelastic peaks from which a soft branch of
underdamped phonons has been established. The model has been used to
calculate a diffuse scattering function which shows above T[c] a
maximum at an incommensurate wave vector located along the L-F line of
the Brillouin zone. The mentioned line is parallel to the ternary
symmetry axis. On the basis of the above results we were able to
visualize the nature of the dynamical monoclinic microdomains
persisting in the high-temperature rhombohedral phase. It has been
shown that above T[c] the fluctuations can be treated as temporary
orientational monoclinic microdomains. Each type of microdomains always
contains an irregular sequence of antiphase domains.
[TYPE]:Phase Diagram and Transformation
[PROP]:Pb[3](PO[4])[2], molecular dynamics, microdomain, order parameter,
dynamical structure factor
******************************************************************************
[ID ]:KL97-343
[AUTH]:Bracht H., Rodriguez-Schachtrup A.
[TITL]:Segregation of Gold at Dislocations Confirmed by Gold Diffusion into
Highly Dislocated Silicon
[SOUR]:Mater. Sci. Forum, 258-263 (1997), 1783-1788
[LAB ]:(2); Univ. Muenster; Suezawa
[ABST]:We report on Au-diffusion experiments performed between 850Ž and
1100Ž into plastically deformed Si monocrystals, undoped and uniformly
doped with a B concentration of 3 times 10]19[cm]-3[. After
indiffusion, Au profiles were monitored with neutron activation
analysis (NAA) in conjunction with mechanical sectioning. The profiles
show Au-diffusion to be faster in heavily B-doped Si than in undoped
samples. Fitting of the experimental profiles which are accurately
described with complementary error functions yields an effective
diffusion coefficient D[Au] and a boundary concentration C[Au](x=0).
Data for D]eff[[Au] and C[Au](x=0) obtained for diffusion temperatures
lower than 1000Ž are considerably lower and higher, respectively, than
expected from the extrapolation based on the high-temperature results.
The unusual temperature dependence of D]eff[[Au] and C[Au](x=0) is
explained taking into account segregation of Au at dislocations in
addition to the kick-out diffusion mechanism which is the generally
accepted process for Au diffusion in dislocation-free Si. The
segregation of Au at dislocations is found to increase with decreasing
temperature with an activation enthalpy of about -1.9eV. From the
influence of doping observed on Au diffusion into dislocated Si, we
deduce that interstitial Au is positively charged in p-type Si and
introduces a donor level at about 0.47eV above the valence-band edge.
[TYPE]:Thermodynamical Properties and Diffusion
[PROP]:Si, gold, diffusion, dislocation, kick-out mechanism
******************************************************************************
[ID ]:KL97-344
[AUTH]:Kamiyama Takashi, Goshi Masahiro, Nakamura Yoshio, Shibata Kaoru and
Suzuki Kenji
[TITL]:Ion Dynamics of Glass-Forming Nitrate Melts
[SOUR]:Prog. Theor. Phys. Suppl., [126] (1997), 415-418
[LAB ]:(2); Dept. of Chem., Faculty of Sci., Hokkaido Univ.; Suzuki
[ABST]:We have studied the RbNO[3]-Sr(NO[3])[2] and Mg(NO[3])[2]-NaNO[3]
systems in the regime of normal liquid and supercooled liquid from
measurements of some dynamical properties. In the periodic table the
difference is only in the sizes of the cations, though the ratio of the
cationic radii is nearly equal. It has been found that in these
glass-forming systems the monovalent cations are main charge carriers,
due to the strong correlation between the divalent cations and the
nitrate anions. The long range translational motion of the monovalent
cation is correlated with the liquid structural motion.
[TYPE]:Thermodynamical Properties and Diffusion
[PROP]:nitrate melts, glass transition, quasielastic neutron scattering
******************************************************************************
[ID ]:KL97-345
[AUTH]:Nonaka Katsuhiko, Kimura Yuuichi, Yamauchi Kazutetsu, Nakajima Hideo,
Zhang Tao, Inoue Akihisa and Masumoto Tsuyoshi
[TITL]:Diffusion in Zr[55]Al[10]Ni[10]Cu[25] Amorphous Alloy with a Wide
Supercooled Liquid Region
[SOUR]:Defect Diffus. Forum, 143-147 (1997), 837-842
[LAB ]:(1); Iwate Univ.; Inoue; Res. Inst. for Electric and Magn. Mater.
[ABST]:This paper reports the result of diffusion measurement in the
supercooled and the amorphous states of Zr[55]Al[10]Ni[10]Cu[25] alloy.
Diffusion measurements were carried out by an ion-beam
sputter-sectioning technique. Self-diffusion of ]63[Ni in
Zr[55]Al[10]Ni[10]Cu[25] amorphous alloy with a wide supercooled liquid
region has been measured in the temperature range from 530 to720K. The
temperature dependence of the diffusivity in the supercooled liquid
phase above the glass transition temperature is significantly different
from that in the amorphous phase. The activation energy for diffusion
in the supercooled liquid phase is much larger than that in amorphous
phase below the glass transition temperature. Diffusion mechanism in
the supercooled liquid and the amorphous phases of the
Zr[55]Al[10]Ni[10]Cu[25] alloy is discussed.
[TYPE]:Thermodynamical Properties and Diffusion
[PROP]:zirconium, amorphous alloy, self-diffusion, supercooled liquid
******************************************************************************
[ID ]:KL97-346
[AUTH]:Ohno Kaoru, Hu Xiao and Kawazoe Yoshiyuki
[TITL]:A CCA Model for Gelation Process in Silica Systems
[SOUR]:Sci. Rep. RITU, A43[1] (1997), 77-82
[LAB ]:(2); Kawazoe; National Inst. for Met., Tsukuba
[ABST]:We propose a new cluster-cluster aggregation model which includes the
expected complex reaction process near the sol-gel transition of a
SiO[2] system. This model explains the experimental fact that the
fractal dimension of the silica-gel shows an interesting dependence on
the amount of the water solvent. We also give a simple analytic result
using mean-field theory.
[TYPE]:Thermodynamical Properties and Diffusion
[PROP]:silica, gelation, sol-gel transition, cluster-cluster aggregation model
******************************************************************************
[ID ]:KL97-347
[AUTH]:Rodriguez-Schachtrup A., Bracht H., Yonenaga Ichiro and Mehrer H.
[TITL]:Diffusion of Gold into Plastically Deformed Undoped and Boron-Doped
Silicon
[SOUR]:Defect Diffus. Forum, 143-147 (1997), 1021-1026
[LAB ]:(2); Inst. fur Metall., Univ. Munster; Suezawa
[ABST]:Diffusion of Au into highly dislocated Si monocrystals undoped and
uniformly boron-doped with a B concentration of C[B]=3 times 10]19[
cm]-3[ has been investigated with the aid of neutron-activation
analysis (NAA) in conjunction with mechanical sectioning. Au profiles
produced at diffusion temperatures of 900Ž, 1000Ž and 1100Ž show Au
diffusion to be enhanced in heavily B-doped Si compared to undoped
samples. The profiles are completely described within the framework of
the kick-out model and a mechanism which accounts for dislocation
induced Au trapping. On the basis of these diffusion mechanisms Au
profiles yield data for the transport capacity C]eq[[Aui]D[Aui] of
interstitial Au. Data deduced for intrinsic conditions are consistent
with corresponding results obtained by Au diffusion in dislocation-free
Si under isoconcentration conditions. The observed doping dependence of
C]eq[[Aui]D[Aui] shows that Aui diffuses as a singly positively charged
impurity in p-type Si which introduces a donor level at about 0.48 eV
above the valence-band edge.
[TYPE]:Thermodynamical Properties and Diffusion
[PROP]:Si, gold, diffusion, dislocation, kick-out mechanism
******************************************************************************
[ID ]:KL97-348
[AUTH]:Bae So Ik, Ichikawa Junichiro, Shimamura Kiyoshi, Onodera Hideya and
Fukuda Tsuguo
[TITL]:Doping Effects of Mg and/or Fe Ions on Congruent LiNbO[3] Single
Crystal Growth
[SOUR]:J. Cryst. Growth, 180[1] (1997), 94-100
[LAB ]:(2); Fukuda; Yamayasu
[ABST]:The doping effects of Mg and/or Fe ions on congruent LiNbO[3] single
crystal growth were studied in order to clarify the roles of MgO in
Fe-doped LiNbO[3] single crystals. The effective distribution
coefficient of Fe was found decreased drastically from 0.85 to 0.5 by
the addition of MgO into the LiNbO[3] melt. Variations of lattice
parameters and optical absorption spectra were dependent on the amount
of Fe rather than that of MgO. Mossbauer spectra revealed that the
addition of MgO reduces the occurrence of Fe]2+[ ions during growth in
air; however, it could not prevent the increase of Fe]2+[ ions during
annealing in Ar. Therefore, it is likely that there would be two
important roles of MgO in Fe-doped LiNbO[3]. One is to suppress the
incorporation of all Fe ions, and the other is to reduce the
concentration of Fe]2+[ ions among the total Fe ions.
[TYPE]:Crystal Growth and Crystal Imperfection
[PROP]:LiNbO[3], congruent composition, distribution coefficient
******************************************************************************
[ID ]:KL97-349
[AUTH]:Bottcher Klaus, Shimamura Kiyoshi and Fukuda Tsuguo
[TITL]:Viscosity Measurement of La[3]Ga[5]SiO[14] Melt
[SOUR]:Cryst. Res. Technol., 32[6] (1997), 769-772
[LAB ]:(3); Fukuda
[ABST]:The viscosity of La[3]Ga[5]SiO[14] melt was measured by a
fixed-crucible rotor technique in the range between 1520 and 1596Ž.
The melt was found to be Newtonian. The viscosity data ranged between
73 and 97mPa cdot s, decreasing with increasing temperature. The
activation energy of the viscous flow and the volume of a viscous flow
unit estimated from the measured data were 90kJ/mol and 3 times 10]-3[
nm]3[, respectively.
[TYPE]:Crystal Growth and Crystal Imperfection
[PROP]:La[3]Ga[5]SiO[14], melt, viscosity
******************************************************************************
[ID ]:KL97-350
[AUTH]:Chani Valery I, Shimamura Kiyoshi, Endo Shinji and Fukuda Tsuguo
[TITL]:Growth of Mixed Crystals of the KTiOPO[4](KTP) Family
[SOUR]:J. Cryst. Growth, 171 (1997), 472-476
[LAB ]:(3); Fukuda
[ABST]:Using appropriate substitutions in KTiOPO[4] (KTP), new crystal
compositions having the same highly stable structure, have been found.
The preparation of Zr]4+[- and V]5+[-substituted crystals of KTP and
KTiOAsO[4] (KTA) is reported. Substitutions of Nb]5+[ - Si]4+[ and
Nb]5+[ - Ge]4+[ for Ti]4+[ - P]5+[ and Ti]4+[ - As]5+[ cation pairs
were studied in an attempt to modify the structure. Results showed that
crystals of composition KTiOAsO[4]: KNbOGeO[4] (1:1) could be grown
from melts of the almost same composition at sim1100Ž. Crystals
prepared from stoichiometric melts had the KTP structure and exhibited
second harmonic generation.
[TYPE]:Crystal Growth and Crystal Imperfection
[PROP]:KTP type structure, nonlinear optical material, crystal growth, SHG,
segregation coefficient
******************************************************************************
[ID ]:KL97-351
[AUTH]:Chani Valery I.
[TITL]:Determination of Equilibrium Cations for the KTiOPO[4] Structure
[SOUR]:J. Mater. Res., 12[9] (1997), 2470-2474
[LAB ]:(3); Fukuda
[ABST]:Single crystals with the structure of KTiOPO[4](KTP) were grown from
mixtures containing equal concentrations of KSnOPO[4] and
KGeOPO[4](i),KTiOPO[4] and KGeOPO[4](ii), and KTiOPO[4] and
KTiOAsO[4](iii), respectively. The comparison of the lattice parameters
measured and calculated from Vegard's rule shows that structural
stability of KTiOAsO[4] is higher in comparison with KTiOPO[4]. It was
found that addition of GeO[2] to the KTP containing flux is accompanied
by increasing all lattice parameters of KTP that correspond to
substitution of As]5+[ by Ge]4+[.
[TYPE]:Crystal Growth and Crystal Imperfection
[PROP]:KTiOPO[4], crystal growth, substitution, cation
******************************************************************************
[ID ]:KL97-352
[AUTH]:Chani Valery Ivanovich, Shimamura Kiyoshi, Endo Shinji and Fukuda
Tsuguo
[TITL]:New Nonlinear Optical Crystals of KTiOPO[4] (KTP) Family
[SOUR]:Mater. Res. Soc. Symp. Proc., 453 (1997), 265-270
[LAB ]:(3); Fukuda
[ABST]:Phase formation and crystal growth conditions for different
combinations of cations corresponding to chemical formula of KTP were
studied. Preparation of new Ti-less arsenates which are isostructural
with KTP is reported. In the single crystals grown Ti]4+[ arsenals were
completely substituted with M]2+[ + Nb]5+[ (M=Mg, Zn) on M]3+[ + Nb]5+[
(M=Al, Cr, Ga, Fe, In) cation couples. The crystals were prepared by
spontaneous crystallization using flux method. The structure analysis
was made by X-ray powder diffraction technique. The crystals
composition was measured by electron probe microanalysis (EPMA). Second
harmonic generation (SHG) effect was studied by the powder technique
with a pulsed YAG:Nd laser (1064nm). SHG signal of the crystals was
found to be slightly greater than that of KTiOAsO[4] (KTA).
[TYPE]:Crystal Growth and Crystal Imperfection
[PROP]:KTiOPO[4], nonlinear optical crystals, crystal growth
******************************************************************************
[ID ]:KL97-353
[AUTH]:Chani Valery Ivanovich, Shimamura Kiyoshi, Endo Shinji and Fukuda
Tsuguo
[TITL]:Substitution of Ti]4+[ with Nb]5+[ - M]3+[ (M = Al, Cr, Ga, Fe, In) in
Crystals of KTiOAsO[4]
[SOUR]:J. Cryst. Growth, 173[1&2] (1997), 117-122
[LAB ]:(3); Fukuda
[ABST]:This study deals with the preparation of K[Nb, M]OAsO[4] (M=Al, Cr, Ga,
Fe, In) single crystals having the structure of KTiOPO[4](KTP) by
spontaneous crystallization from a flux. It has been found that the
replacement of P]5+[ cation on the tetrahedral sites of K[Nb,
Ga]OAsO[4] decreases the phase formation field and the stability of KTP
structure. Therefore, the formation of K[Nb, M]OPO[4] compounds was not
observed. The region in which KTP phase formation occurs is indicated
in a ternary diagram. Crystal composition was measured by electron
microprobe analysis and second harmonic generation was studied by
powder technique. Segregation phenomena are also discussed.
[TYPE]:Crystal Growth and Crystal Imperfection
[PROP]:KTiOAsO[4], flux method, aliovalent analogous, SHG
******************************************************************************
[ID ]:KL97-354
[AUTH]:Chani Valery Ivanovich, Yu Young Moon, Shimamura Kiyoshi, Saiki Yasushi
and Fukuda Tsuguo
[TITL]:Crystal Growth of Ca[3](Li, Nb, Ga)[5]O[12] Garnets from Melt
[SOUR]:Mater. Res. Soc. Symp. Proc., 453 (1997), 283-288
[LAB ]:(2); Fukuda; Korea Res. Inst. of Chem. Technol.
[ABST]:Single crystals of Ca[3](Li, Nb, Ga)[5]O[12] garnets have been grown
from stoichiometric melts by micro-pulling down and Czochralski methods
using Pt crucibles. It was found that the mixture of oxides with atomic
ratio Ca:Li:Nb:Ga=3:0.275:1.775:2.95 correspond to the garnet
composition which melts congruently at about 1450Ž. Solid state
reaction data of the compounds related with this material are also
reported. Lattice parameter of all Ca[3](Li, Nb, Ga)[5]O[12] crystals
grown was about 1.254nm. Transparent and bubble-free crystals of
Ca[3]Li[x]Nb[(1.5+x)]Ga[(3.5-2x)]O[12] (x=0.25 and 0.275) were grown by
Czochralski technique in air. An optical transmission spectrum of the
crystals was studied. No absorption was detected in 400-1200nm
wavelength range.
[TYPE]:Crystal Growth and Crystal Imperfection
[PROP]:Ca[3](Li, Nb, Ga)[5]O[12], garnet crystal, melt growth, Czochralski
method, fiber crystal
******************************************************************************
[ID ]:KL97-355
[AUTH]:Epelbaum Boris M.
[TITL]:Micro-Pulling Down Growth Studies of Lead Tungstate Crystals: Aspects
of Incongruent Melt Vaporization
[SOUR]:J. Cryst. Growth, 178[3] (1997), 426-429
[LAB ]:(3); Fukuda
[ABST]:The problem of increasing yellow coloration of PbWO[4] crystal grown
from the melt has been analyzed using a micro-pulling down technique.
The ratio of free surface area to melt volume in mu-PD growth is
noticeably higher in comparison with CZ method. The incongruent
vaporization of PWO melt generates changes in stoichiometry and
subsequently causes difficulties for crystal growth from
tungsten-excess melt.
[TYPE]:Crystal Growth and Crystal Imperfection
[PROP]:PbWO[4], crystal growth, stoichiometry, incongruent vaporization
******************************************************************************
[ID ]:KL97-356
[AUTH]:Epelbaum Boris Marovich, Gurjiyants Pavel A, Inaba Katsuhiko, Shimamura
Kiyoshi, Uda Satoshi, Kon Junichi and Fukuda Tsuguo
[TITL]:Origin of SiC Precipitation during the Micro-Pulling-Down Processing of
Si-Ge Fibers
[SOUR]:Jpn. J. Appl. Phys., 36[5A] (1997), 2788-2791
[LAB ]:(2); Fukuda; Inst. of Solid State Phys., Chernogolovka, Russia
[ABST]:The problem of SiC precipitation during micro-pulling-down growth of
Si=Ge mixed crystals has been analyzed as an important constraint of
the technique. Three mechanisms of SiC microcrystal formation have been
discussed. The solute transport in the melt and the dependence of the
rate of Si-Ge melt evaporation on melt composition have been
investigated. The troublesome influence of CO on SiC formation has been
reduced by modification of the micro-pulling-down (mu-PD) growth
assembly with optimization of argon flow. As a result the effective
lifespan of the crucible was increased at least fivefold.
[TYPE]:Crystal Growth and Crystal Imperfection
[PROP]:Si-Ge, SiC, fiber crystal, micro-pulling-down method
******************************************************************************
[ID ]:KL97-357
[AUTH]:Epelbaum Boris Marovich, Inaba Katsuhiko, Uda Satoshi, Shimamura
Kiyoshi, Imaeda Minoru, Kochurikhin Vladimir Vladimirovich and Fukuda
Tsuguo
[TITL]:A Double-Die Modification of Micro-Pulling-Down Method for