bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of High-Tc Superconducting Y-Ba-Cu-O Ceramics and Their Grain Morphologies
Authors: Kuwabara Makoto
Published: November 2005

High-T
c superconducting Y-Ba-Cu-O ceramics have been prepared using the commercial reagent grade Y2O3, BaC2O4·H2O and CuC2O4·1/2H2O as the starting materials under various sintering conditions. The ceramic microstructure (grain size and relative sintered density) has been confirmed to have a significant influence on the electrical conductivity, but less influence on the superconducting transition temperature, T
c.
Structures and Superconducting Properties of Y-Ba-Cu-O Sputtered Films
Authors: Komuro Matahiro , Kozono Yuzoo , Yazawa Yoshiaki , Ohno Toshiyuki , Hanazono Masanobu , Matsuda Shinpei , Sugita Yutaka
Published: November 2005

Y-Ba-Cu-O thin films were prepared by an RF magnetron sputtering technique. When annealed at temperatures between 920°C and 1000°C the crystal structures of these films are orthorhombic, while when annealed at 1010°C the structures are tetragonal. Superconductivity can be observed for the orthorhombic films. Their critical temperature (T
c) of superconducting becomes higher as the a-axis becomes shorter, and is independent of the b-axis value.
Hydrogen Incorporation Scheme in a-Si1-xCx: H
Authors: Kumeda Minoru , Nakanishi Satoko , Shimizu Tatsuo
Published: November 2005

A hydrogen incorporation scheme is investigated in a-Si1-x
C
x
:H using NMR and is compared with the density of dangling bonds. The network of a-Si1-x
C
x
:H with x<0.2 is classified into two phases with dispersed and clustered H atoms, as is well known in a-Si:H. The total H content increases with increasing x up to ∼0.2, but the dispersed H atom content decreases accompanied by an increase in the density of dangling bonds. With x>0.2, the average separation between dispersed H atoms becomes closer and an H-poor region with a high density of dangling bonds arises.
Pressure Studies on Anomalous Dielectric Behavior in Ferroelectric Liquid Crystals
Authors: Ozaki Masanori , Yasuda Naohiko , Yoshino Katsumi
Published: November 2005

Anomalous dielectric behaviors in 3M2CPOOB with extremely large spontaneous polarization P
s and in 2MBNCBC indicating the reversal of the sign of the P
s have been studied under hydrostatic pressure up to 2 kbar. The slope of the pressure-temperature phase diagram was comparable to that of DOBAMBC and other smectic liquid crystals, suggesting that the ferroelectricity is not influenced strongly. Anomalies in both compounds were not influenced by the application of pressures of less than 2 kbar.
Growth of Epitaxial Layers of In Doping GaAs by the Vapour-Phase Epitaxial Trichloride Method Using a Gallium-Indium Alloyed Source
Authors: Coronado M. Lõpez , Abril E. J. , Aguilar M.
Published: November 2005

In this letter we report on the In doping of GaAs layers grown by VPE (Chloride Method) using a Ga/In alloyed source. This work contribute to understanding the influence on the isoelectronic doping of parameters such as the source and deposition temperature, the input AsCl3 molar fraction and a HCl excess in the deposition zone, in order to determine the optimum isoelectronic doping conditions in a buffer layer.
Anomalous Magnetization Processes at Low Temperatures in Compositionally Modulated Co/Mn Thin Films
Authors: Sakakima Hiroshi , Tessier Michel , Krishnan Ramanathan , Hirota Eiichi
Published: November 2005

Compositionally modulated Co/Mn thin films with layer thickness ranging from 7-70 Å were prepared by UHV evaporation. The artificial periodicity was confirmed by small-angle X-ray diffraction. Magnetization of the CMF was found to decrease below a certain transition temperature and anomalous magnetization processes were observed at low temperatures.
A Modified Wheatstone Bridge for High-Precision Automated Resistance Measurement
Authors: Sasaki Hitoshi , Nishinaka Hidefumi , Shida Katsunori
Published: November 2005

A modified Wheatstone bridge has been developed which auto-balances using a digitally controlled feedback system. The bridge has four detectors to sense the imbalance in the circuit, and a resolution of better than 0.01 ppm with nearly maintenance-free operation.
Superconductivity in Impurity-Induced Tetragonal YBa2(Cu1-xFex)3O7-δ
Authors: Maeno Yoshiteru , Kato Masatsune , Aoki Yuji , Fujita Toshizo
Published: November 2005

Lattice deformation and superconductivity in YBa2(Cu1-x
Fe
x
)3O7-δ are studied in detail. An orthorhombic to tetragonal phase change is induced at x
c≈0.02. A phase diagram in the temperature-concentration plane clarifies two regions of the tetragonal phase: one is, as known previously, induced mainly by the release of oxygen, and the other by the direct action of impurities. Bulk nature of superconductivity in the novel impurity-induced tetragonal phase is confirmed by magnetic susceptibility measurements.
Preparation of Superconductive YBa2Cu3O7-x Thick Films by the Rapid-Quenching Technique
Authors: Takahashi Koichiro , Shimomura Shuichi , Nagasawa Arata , Ohta Masatsune , Kakegawa Kazuyuki
Published: November 2005

Thick films of YBa2Cu3O7-x
(e.g. 50 µm thick × 13 mm wide × 45 mm long) with maximum density were prepared by rapid quenching. For the film heat-treated at 950°C in air, superconductivity was realized with an onset temperature of 98 K and zero resistivity of 87 K.
Absorption and Emission Spectral Changes in a Poly(3-Alkylthiophene) Solution with Solvent and Temperature
Authors: Yoshino Katsumi , Nakajima Shigeaki , Gu Hal Bon , Sugimoto Ryu-ichi
Published: November 2005

A remarkable change of the absorption spectrum has been observed in poly(3-alkylthiophene) solutions with changing temperature, which is tentatively interpreted in terms of a conformation change of polymer chains such as a rod-coil transition due to the change of the entanglement of alkyl chains with temperature. The emission intensity has been found to decrease remarkably at low temperature due to this transition.
A Transverse Electron Beam Source for the Excitation of CW Lasers
Authors: Guo Xiaoguang , Hara Tamio , Sanda Atsuo , Hamagaki Manabu , Fusayama Takao , Kim Pil Hyon , Namba Susumu
Published: November 2005

A novel transverse electron beam gun for the excitation of cw ion lasers is reported. The electron beam is extracted from glow discharge plasma using a short gap of electrodes. Electron beam energy and current can be controlled independently.
Output Characteristics of a Gas-Polarographic Oxygen Sensor Using a Zirconia Electrolyte in the Knudsen Diffusion Region
Authors: Usui Toshio , Nuri Kenji , Nakazawa Mitsuhiro , Osanai Hiroshi
Published: November 2005

Output characteristics of a gas-polarographic oxygen sensor using a zirconia electrolyte have been investigated at 450°C and low pressures (∼1 mmHg) in O2-N2 gas mixtures with the aim of clarifying those in the Knudsen diffusion region. The limiting current obtained at 1 mmHg of the total pressure increased linearly with the oxygen concentration up to 100% in the ambient atmosphere as expected from the theoretical consideration on the output characteristics of the sensor in the Knudsen diffusion region.
Strongly Induced Perpendicular Anisotropy in Magnetic Thin Films by Micro-Fabrication
Authors: Hatta Shin-ichiro , Shiono Teruhiro , Adachi Hideaki , Wasa Kiyotaka
Published: November 2005

Strong perpendicular anisotropy was induced by micro-fabrication in magnetic thin films in which isolated magnetic micro-pillars were regularly formed on the surface. The result indicated that most of the films with in-plane anisotropy may be changed to perpendicularly magnetized recording media.
Crystal Structure of Ternary Ba8YCu4O16-d Phase
Authors: Osamura Kozo , Zhang Wei
Published: November 2005

A new ternary phase in the Ba-Y-Cu-O system is reported. It has a tetragonal structure with a space group of D4h
l. The chemical composition is typically expressed as Ba8YCu4O16-d
, and the lattice constants are a = 0.8138 and c = 0.8096 nm (c/a = 0.994). The phase was suggested to have a limited composition region of stoichiometry because the lattice spacing changes with the composition of the specimen.
Low Temperature Preparation of Hydrogenated Amorphous Silicon by Microwave Electron-Cyclotron-Resonance Plasma CVD
Authors: Kitagawa Masatoshi , Ishihara Shin-ichiro , Setsune Kentaro , Manabe Yoshio , Hirao Takashi
Published: November 2005

Hydrogenated amorphous silicon films were deposited by microwave electron-cyclotron-resonance plasma CVD technique using pure mono silane gas without intentional substrate heating. A high photoconductivity value of 10-6∼10-5(Ω·cm)-1 under simulated AM1 (100mW/cm2) illumination was obtained for the as-grown films with optical gaps of ∼2.1 eV. Localized tail states estimated from optical absorption measurements are discussed with the characteristics of the films.
Viscosity Measurement in Ferroelectric Liquid Crystals Using a Polarization Switching Current
Authors: Kimura Satoshi , Nishiyama Shin-ichi , Ouchi Yukio , Takezoe Hideo , Fukuda Atsuo
Published: November 2005

A new method to evaluate rotational viscosity η in ferroelectric liquid crystals is proposed. This method is based on the measurement of a polarization switching current upon field reversal. It is shown that a full width at half-maximum of the current peak t
w is equal to 1.76η/P
s
E, while the area gives twice the spontaneous polarization P
s. It is also shown that the sign of a dielectric anisotropy Δε is determined by the asymmetrical shape of the signal. A proportionality between t
w and E
-1 was confirmed for a surface stabilized ferroelectric liquid crystal cell. The temperature dependences of P
s and η are presented.
Fabrication of Submicron Grating Patterns Usinc Compositional Disordering of AlGaAs-GaAs Superlattices by Focused Si Ion Beam Implantation
Authors: Ishida Koji , Miyauchi Eizo , Morita Tetsuo , Takamori Takeshi , Fukunaga Toshiaki , Hashimoto Hisao , Nakashima Hisao
Published: November 2005

Submicron grating patterns (0.4 µm period) were fabricated in AlGaAs-GaAs superlattices (SL's) using compositional disordering of SL's by focused Si ion beam implantation and subsequent annealing. The grating structure which is composed of preserved SL and mixed (disordered) regions was confirmed by scanning electron microscopic (SEM) and scanning Auger microscopic (SAM) observations.
UHV-REM Study of Changes in the Step Structures on Clean (100) Silicon Surfaces by Annealing
Authors: Inoue Naohisa , Tanishiro Yasumasa , Yagi Katsumichi
Published: November 2005

Changes in the step structures on clean (100) silicon surfaces during annealing were observed by in situ ultra high vacuum reflection electron microscopy. After quenching from 1200°C, at about 800°C almost the entire surface was covered with periodic arrays of 2×1 and 1×2 reconstructed domains bounded by monolayer high steps. One type of reconstructed domain, with dimers parallel to the average tilt axis [011̄], grew over the other above 900°C. The terrace size became as large as a few microns. However, a small number of periodic arrays of reconstructed domains remained stable at above 1000°C even under apparent surface evaporation.
Effect of Atomic Force on the Surface Corrugation of 2H-NbSe2Observed by Scanning Tunneling Microscopy
Authors: Bando Hiroshi , Tokumoto Hiroshi , Mizutani Wataru , Watanabe Kazutoshi , Okano Makoto , Ono Masatoshi , Murakami Hiroshi , Okayama Shigeo , Ono Yuichi , Wakiyama Shigeru , Sakai Fumiki , Endo Kazuhiro , Kajimura Koji
Published: November 2005

Anomalously large surface corrugation of 2H-NbSe2crystal was observed by scanning tunneling microscopy (STM). Besides mounds representing the Se atoms, hollow sites and Nb-atom sites clearly appeared as dips and saddle points, respectively. The lateral resolution was proved to be better than 0.2 nm. The large corrugation amplitude was attributed to the effect of atomic force between the tip and the sample.
Ferromagnetic Resonance of Gd-Eu-Co Alloy Thin Films
Authors: Wakishima Osamu , Uemura Toshimasa , Okuno Hikaru , Sakaki Yo
Published: November 2005

Ferromagnetic resonance (FMR) is investigated on (Gd1-x
Co
x
)1-y
Eu
y
alloy thin films (Co rich; x∼0.85) in a temperature region between 77 K and 400 K with variation of Eu concentration. Effective magnetization and g-value determined using Kittel's formula depend on the Eu concentration. At 77 K g-value is nearly constant at low concentration, however, it shows an abrupt increase at y=0.10. The Co moment is almost cancelled by Eu and Gd spins at this concentration. A possible model is proposed to explain the experiments.
Electronic Origin of Distortion of Oxygen Octahedron in (La1-xMx)2CuO4 with M=Ca, Sr and Ba
Authors: Terakura Kiyoyuki , Ishida Hiroshi , Park Key Taeck , Yanase Akira , Hamada Noriaki
Published: November 2005

In the high T
c material (La1-x
M
x
)2CuO4 the oxygen octahedral cage surrounding a Cu atom is strongly distorted, and the change of T
c accompanied by substitution of La with M(=Ca, Sr and Ba) is correlated with the Cu-O distance in the basal ab plane. The microscopic origin of the large distortion of the oxygen octahedron is discussed.
Magnetization and Meissner Effect in the High Tc Superconductor BaxY1-xCuO3-y
Authors: Tokumoto Madoka , Hirabayashi Masayuki , Ihara Hideo , Murata Keizo , Terada Norio , Senzaki Kiyoshi , Kimura Yoichi
Published: November 2005

Magnetization and Meissner effect measurements of the high T
c superconductor Ba0.6Y0.4CuO3-y
, with the (Ba
x
Y1-x
)6Cu6O14 structure and a sharp resistive transition at 90 K, are reported. Diamagnetic susceptibility was observed below 90 K, indicating a bulk superconductivity. The magnetization measurement revealed a characteristic feature of a type-II superconductor with H
c1(0)=1∼2 kOe and strong pinning.
ZnS:Mn Thin Film Electroluminescent Devices Having Doubly-Stacked Insulating Layers
Authors: Mita Juro , Koizumi Masumi , Kanno Hiromasa , Hayashi Tadashi , Sekido Yoshihiro , Abiko Ichimatsu , Nihei Kohji
Published: November 2005

ZnS:Mn thin film electroluminescent devices having doubly-stacked insulating layers have been developed. The insulating layer consists of electron-beam evaporated Ta2O5, and rf-magnetron sputtered SiO2 stacked layers. It is concluded that the thick semi-insulating Ta2O5 films (1000 nm) deposited on both sides of the ZnS:Mn active layer act as a carrier injctor for electroluminescence and the thin insulating SiO2 films (80 nm) inserted between the electrodes and Ta2O5 films act as a carrier limiter. The breakdown voltage margin defined by (V
bd-V
th)/V
th was improved from 15% to more than 80% by introducing thick semi-insulating Ta2O5 films.
Optimization of High-Efficiency n+-p-p+ Back-Surface-Field Silicon Solar Cells
Authors: Morita Keiichi , Saitoh Tadashi , Uematsu Tsuyoshi , Kida Yasuhiro , Kokunai Shigeru , Matsukuma Kunihiro
Published: November 2005

High-efficiency silicon solar cells are fabricated with back-surface-field (BSF) structures using medium-resistivity, float-zone substrates. The cell processes are optimized using a new BSF process in order to maintain a high minority-carrier lifetime. In addition, they are improved with a passivated, V-grooved surface to enhance collection efficiency. The resultant cells exhibit conversion efficiencies of 19.1% with a short-circuit current density of 38.4 mA/cm2. The minority-carrier lifetime and surface recombination velocity are estimated to be 341 µs and 3×105 cm/s using a computer program.
Microanalysis by Focused MeV Helium Ion Beam
Authors: Takai Mikio , Matsunaga Kouji , Inoue Kenichi , Izumi Masahiro , Gamo Kenji , Sato Mamoru , Namba Susumu
Published: November 2005

A microbeam line with 1.5 MeV helium ions for Rutherford backscattering (RBS) and particle-induced X-ray emission (PIXE) measurements has been realized by piezo-driven objective slits and a magnetic quadrupole doublet. A minimum beam spot size of 1.3 µm×2.2 µm was obtained. Secondary electron and Rutherford backscattering mapping images were demonstrated.
Far-Infrared Laser Oscillation in p-Ge Using External Reflectors
Authors: Komiyama Susumu , Kuroda Shinji
Published: November 2005

Intervalence band laser oscillation in p-Ge is achieved in a semiconfocal resonator system using external reflectors and the directivity of the output radiation is thereby largely improved. The spectrum of the radiation consists of several discrete lines due to simultaneous oscillations in multimodes. Preliminary attempts to select a single oscillation line by means of Fabri-Perot type interference are also described.
Effect of Oxygen Deficiency on the Crystal Structure and Superconducting Properties of the Ba2YCu3Oy
Authors: Kubo Yoshimi , Yoshitake Tsutomu , Tabuchi Junji , Nakabayashi Yukinobu , Ochi Atsushi , Utsumi Kazuaki , Igarashi Hitoshi , Yonezawa Masatomo
Published: November 2005

Effect of oxygen deficiency on crystal structure and superconductivity of Ba2YCu3O7-δ was studied by annealing and quenching experiments. With increasing oxygen deficiency superconductivity was suppressed remarkably while axial ratio, a
0/b
0 in the orthorhombic phase approached to unity and c
0 value increased. Structural transformation from orthorhombic to tetragonal lattice took place in the temperature range, 950∼980°C and maximum oxygen deficiency, δ=0.7 was observed for the tetragonal phase.
Anomalous Decrease of Resistance and Increase of Diamagnetism Above 77 K in Ultrathin Au-Nb Film on Single-Crystal Silicon
Authors: Yamamoto Hiroshi , Watanabe Akinobu , Tanaka Masaichi
Published: November 2005

A number of Au-Nb films as thin as a few nm were deposited onto clean (100) surfaces of single-crystal silicons. Some specimens exhibited anomalous fall-off of the sheet resistance and remarkable enhancement of the diamagnetism on the way of decreasing temperature from 300 K to 77 K. In addition, nonlinear diamagnetic responses to the magnetic field extending to 14 kOe were observed at 77 K. The results are discussed in terms of the extended Allender-Bray-Bardeen model for the high-temperature superconductivity expected to take place on highly fluctuated interface of metal-semiconductor.
On the Phase Relation between Two Polymorphs of Ba1.8Y1.2Cu3O6.7-δ and Their Oxygen Contents
Authors: Nakamura Keikichi , Hatano Takeshi , Matsushita Akiyuki , Oguchi Tamio , Matsumoto Takehiko , Ogawa Keiichi
Published: November 2005

The relation between the oxygen deficiency δ and the the two polymorphs of Ba1.8Y1.2Cu3O6.7-δ, i.e., orthorhombic and tetragonal phases, have been studied by the gravimetric method combined with the X-ray diffraction analysis. The oxygen deficiency δ was varied by annealing the samples in an argon or oxygen atmosphere at an appropriate temperature, followed by rapid quenching to room temperature. It is shown that the tetragonal phase is characterized by a large oxygen defficiency, δ=0.6-0.7, suggesting that oxygen occupancy factor at z=1/2 of the structural model proposed by Siegrist et al. [submitted to Phys. Rev. lett.] is nearly zero.
Preparation and Superconducting Properties of the Ba1-xYxCuO3-y Compounds
Authors: Ohshima Shigetoshi , Wakiyama Tokuo
Published: November 2005

The Ba1-x
Y
x
CuO3-y
compounds with x ranging from 0.1 to 0.6 were prepared under various sintering conditions. The Ba0.66Y0.34CuO3-y
compound, prepared by sintering at 950°C for 24 hours after presintering at 950°C for 1 hour, showed superconductivity with T
c onset=90 K, T
c midpoint = 88 K and T
c end = 85 K. The compound is a single phase of oxygen-defect perovskite. Magnetization curves were measured at 77 K and the values of H
c1 were estimated.
Motion of Fluid Driven by Electro-Thermally Ablated Gas Pressure
Authors: Ikuta Kazunari
Published: November 2005

We study the motion of fluid driven by electro-thermally ablated gas pressure in a cavity with a single exhauster. A possibility of jet propulsion engine for steamers is also discussed as an application of the fluid motion.
Superconductivity of Sr-La-Cu Oxides Prepared by Coprecipitation Method
Authors: Saito Yoshitami , Noji Takashi , Endo Akihiko , Matsuzaki Nozomu , Katsumata Masao , Higuchi Naoaki , Ono Mikiya
Published: November 2005

Superconducting properties in Sr-La-Cu-O system prepared by the coprecipitation method were studied. The highest T
c of the samples was about 42 K, rather higher than that of the samples by a solid-state reaction. It was found that the composition (especially that of Sr) of the sintered samples was different from the nominal formation.
Superconductivity in the La-Cu-O System
Authors: Sekizawa Kazuko , Takano Yoshiki , Takigami Hiroyuki , Tasaki Seiji , Inaba Takamichi
Published: November 2005

A superconducting transition with an onset temperature of about 40 K has been observed in the La-Cu-O system which is not doped with alkaline earth ions. The compounds with nominal compositions, La2CuO4-δ, La3Cu2O
y
and La4Cu3O
z
were prepared. In this system, the occurrence of superconductivity is attributed to the orthorhombic (distorted K2NiF4 type) phase. The superconducting transition occurs following a semiconductor-like increase in the resistivity with decreasing temperature, which is characteristic of the low carrier density superconductors. The effects of an annealing in oxygen at atmospheric pressure are also reported.
A Single Crystal High Temperature X-Ray Study of Orthorhombic Ba2YCu3-xO7-y Superconductor
Authors: Sueno Shigeho , Nakai Izumi , Okamura Fujio P. , Ono Akira
Published: November 2005

An orthorhombic superconductor with composition Ba2YCu3-x
O7-y
was investigated at the temperature range of 24°C-600°C by single crystal X-ray diffraction method. All of the `single crystals' examined showed twinning of which the law can be explained by the point symmetry, suggesting the origin of the twinning is a transition from a tetragonal phase in cooling process. Through heating experiments, it was confirmed that these crystals show reversible orthorhombic-tetragonal transition at 575°C.
Structural Properties of a High-Tc Superconductor Ho-Ba-Cu Oxide Studied by Transmission Electron Microscopy
Authors: Takeda Seiji , Hikami Shinobu
Published: November 2005

The crystal structure of the Ho-Ba-Cu oxide, which is responsible for high T
c superconductivity, has been investigated by transmission electron microscopy. The lattice belongs to an orthorhombic system with lattice parameters a=3.83 Å, b=3.90 Å and c=11.8 Å. It is an isomorphous structure of the high-T
c superconductor Y-Ba-Cu oxide. Micro twinning of crystal is observed under the high spatial resolution, that is 3 Å. The twinned crystals could be observed with incident electron beam parallel to a, b and c-axes of the crystal. It is concluded that the Cu layers expand in the a-b planes even across the twin boundary without any kink.
Single Crystal Preparation of Ba2YCu3Ox from Nonstoichiometric Melts
Authors: Takekawa Shunji , Iyi Nobuo
Published: November 2005

Single crystals of Ba2YCu3O
x
were grown from nonstoichiometric melts in the system Ba-Y-Cu-O. From the melt having the composition BaO:YO1.5:CuO = 12:1:26, single crystals in rectangular form with the size up to 0.5 mm were grown together with thin plates up to 2 mm with the thickness of about 30 µm. They have tetragonal symmetry with the cell parameters a = 3.862 Å and c = 11.80 Å. The measurement of the electrical resistivity revealed that their resistivity was about 4 Ωcm at room temperature and that the superconducting transition did not occur down to 65 K.
Critical Current Density of Wire Type Y-Ba-Cu Oxide Superconductor
Authors: Yamada Yutaka , Fukushima Noburu , Nakayama Shigeo , Yoshino Hisashi , Murase Satoru
Published: November 2005

We have fabricated wire type Y-Ba-Cu oxide superconductor by powder metallurgy technique. A large critical current density J
c of 7.25 × 102 A/cm2 at 77 K and 0 T and the resistive T
c transition of 89 K to 87 K were obtained for the wire type conductor heat treated without Cu sheath. However, the J
c(77 K) drastically decreased by a factor of 200, applying a magnetic field of 1 T. On the contrary, J
c(4.2 K) little changed; 1.63 × 102 A/cm2 at 1 T and 1.33 × 102 A/cm2 at 12 T. Based on the magnetic field dependence of J
c, we estimate upper critical field Bc2 (i.e. corresponding to Bc2 defined by T
c (offset)) and GL coherence length ζ.
Low Temperature Epitaxial Growth of Highly-Conductive ZnSe Layers in Mixed Plasma of Hydrogen and Hydrogen Chloride
Authors: Yamauchi Satoshi , Hariu Takashi , Matsushita Koichi
Published: November 2005

Highly conductive ZnSe layers with resistivitv of 10-3 Ω·cm (electron density: 2.8×1019 cm-3, Hall mobility: 140 cm2/Vs) have been grown on (100)GaAs by plasma-assisted epitaxy at 318°C in a mixed plasma of hydrogen and HCl. However, photoluminescent measurements suggest that excessive doping above 1019 cm-3 reduce the conductivity from its maximum value by inducing complex defects.
Stable Field Emission of Electrons from Liquid Metal
Authors: Hata Koichi , Ohya Ryuichi , Nishigaki Satoshi , Tamura Hifumi , Noda Tamotsu
Published: November 2005

Experiments were carried out on the field emission of electrons from Ga-In-Sn liquid alloy and a stable DC emission was observed in addition to the pulse explosion already reported. The emission stability depended on the apex radius of the tungsten tip to which the liquid metal adhered to form a cone. When we used an emitter with an apex radius smaller than 0.5 µm, Fowler-Nordheim plots in the DC mode were heavily influenced by the adhesive state at its surface.
Doping-Induced Defects in P-Doped Photo-CVD a-Si:H
Authors: Suzuki Kazuhiko , Kominato Toshimi , Takeuchi Hiroshi , Kuroiwa Koichi , Tarui Yasuo
Published: November 2005

Doping-induced defect creation of photo-CVD amorphous silicon is investigated by photoluminescence and the isothermal capacitance transient spectroscopy technique. The defects induced by phosphorus doping increase as the square root of the gas phase doping ratio, indicating Street's doping mechanism is basically valid for the Hg-sensitized photo-CVD a-Si:H.
Gel Formation in Polyvinyl Alcohol Film by Heat Treatment after Exposure to Ultra-violet Light
Authors: Mori Masatake , Kumagai Michikazu
Published: November 2005

The physical properties of polyvinyl alcohol are found to be changed by exposure to ultra-violet light followed by heat treatment as in the case of high energy radiations. When polyvinyl alcohol is irradiated in air by ultra-violet light, carbonyl groups are produced. The heat treatment of irradiated polyvinyl alcohol above 120°C in a silicone oil bath produces crosslinkages between molecular chains.
Propriétés Electroluminescentes des Phosphores du Type Zn(S : Se) : Cu
Authors: Asano Sumitada , Nakao Yasuhiro
Published: November 2005

The electroluminescent phosphors Zn(S : Se) activated with Cu and Cl, and those activated with Cu and Al were prepared, and the spectral distribution, temperature dependence and voltage dependence were measured. In addition, some thermoluminescence measurements were made, which are important in interpreting the electroluminescent behaviors. The phosphors containing large proportion of ZnSe show pronounced temperature quenching at room temperature. Their emission band considerably broadens and tends to be separated into two bands at 77°K. The experimental results suggest that the ionized centers in these phosphors tend to recombine with electrons in valence band by thermal excitation.
Single Crystal Film of Ferrites
Authors: Takei Humihiko , Takasu Shin'ichiro
Published: November 2005

Single crystal films of NiFe2O4, CoFe2O4 and FeFe2O4 were prepared epitaxially by decomposing the respective metal halides with water vapor on the cleaved (100) surface of MgO crystal. The thickness of the film was varied over the range from several µ to about 100µ by changing experimental conditions. X-ray diffraction analysis showed that the films were of spinel structure and the crystal axis was always parallel to that of MgO substrate. Ferromagnetic resonance measurement and chemical analysis of NiFe2O4 film suggested a slightly uneven distribution of the components along the direction perpendicular to the substrate surface.
Dendrite Crystals of Metallic Selenium Grown from Vapor
Authors: Furuta Noboru
Published: November 2005

The dendrite crystals of metallic Se grown from the vapor with the supersaturation ratio maintained constant at 25 to 100 can be classified into five groups depending on the shape and crystal structure. The growth mechanism of these dendrite crystals except one group relates to the twinning. The difference in the shape of these denddrite crystals mainly comes from the number of twin boundaries contained therein and the mutual relations between them. The growth of dendrite crystals containing two twin boundaries mainly starts at the steps and kinks formed by overlapping of two thin films originating from each boundary.
Anomalous Dispersion of Coercive Field at Very Low Frequencies and A Jerky Wall Motion in Rochelle Salt
Authors: Abe Ryuji
Published: November 2005

An optical method1) was used to study the dependences of coercive field on temperature and frequency of very low frequency region. From the analysis of the data following conclusions are obtained:
(1) The dependence of coercive field on frequency at 0°C can be explained satisfactorily if the velocity of the wall motion is assumed to be proportional to exp
-(α/E), where E is an applied field. The value of α was determined to be about 190 volt/cm from the experimental data.
(2) The temperature at which the coercive field is maximum decreases with the decrease of frequency and it becomes finally about 2°C at 0.004 cps. This dependence of coercive field on frequency and temperature can be explained by assuming that a certain Schottky defect, probably the defect of H2O molecule, prevents the faster movement of the domain wall.
A Method of Measurement of Plasma Conductivity. II. –Example of Measurement–
Authors: Tanaca Hiroshi , Hagi Mikiko
Published: November 2005

A measurement of plasma conductivity is described, which is based on the method theoretically discussed in the previous note. The plasma tube is inserted in a single turn coil of a LC oscillator, and the shift in the resonance frequency, Δf, due to the insertion is observed. From Δf the change in the magnetic flux penetrating the coil can be evaluated, and from the latter the plasma conductivity can be determined. The results are in satisfactory agreement with the conductivity values obtained by the usual probe method.
Redistribution of Diffused Boron in Silicon by Thermal Oxidation
Authors: Kato Taketoshi , Nishi Yoshio
Published: November 2005

Redistribution phenomena of diffused boron due thermal oxidation of silicon have been studied.
Mathematical formulation of the redistribution phenomena is proposed and analytical solution of the problem is given approximately by the method of Green's function. Numerical calculations are carried out for several combinations of physical constants and compared with experiment.
The redistribution phenomena are well described by the model in which the growth of oxide occurs at the silicon-silicon dioxide interface and out diffusion of boron through the oxide film is negligibly small. The experiments have been performed in the range of 1180°–1230°C under one atmospheric pressure of dry oxygen and the segregation coefficient is determined to be about 10 in this temperature range.
Electron Spin Resonance Studies of Irradiated Polyethylene. II. Considerations on the Decays of Free Radicals
Authors: Kashiwabara Hisatsugu
Published: November 2005

Decays of the free radicals of an alkyl type trapped in irradiated polyethylene were investigated by means of electron spin resonance method. It was found that, in the temperatures ranged from 77°K to 350°K, there are three regions of temperatures, near 140°K, 200°K and 240°K, at each of which alkyl type free radicals decay rather “transitionally”. These regions are corresponding to the temperature regions of mechanical dispersions in polyethylene except that near 200°K. Decays of the free radicals were considered in connection with the molecular motion of polyethylene associated with the mechanical dispersion. The relations between the narrowing of line width and the decay of free radicals were also considered briefly.
Phase Diagram of the Partial System of MnSi-Si
Authors: Fujino Yoshio , Shinoda Daizaburo , Asanabe Sizuo , Sasaki Yozo
Published: November 2005

A phase diagram of the system MnSi-Si containing Si in the range from 45.00 to 57.00 wt% is determined by the methods of X-ray, metallographic and thermal analyses and also by the electrical measurements. It is found that the intermetallic compound in this system is MnSi1.72. This compound has the maximum melting point of about 1145°C in the neighboring composition range. A single crystal of MnSi1.72 is obtained by the Czochralski method.
Viscoelastic Behavior of Copolymers of Methyl Methacrylate and n-Butyl Methacrylate and Glass Polishing by Use of Them
Authors: Wada Yasaku , Hirose Hidenori , Kasahara Tetsuo
Published: November 2005

In the first part of the work, shear creep compliance is measured for six kinds of copolymers of methyl methacrylate and n-butyl methacrylate above the respective glass transition temperatures. Shift factors and retardation spectra are calculated therefrom. The molecular weight between entanglement points which is obtained from the maximum of spectrum increases with the increase in n-butyl methacrylate fraction. This effect is interpreted in terms of the plasticizer effect of side chains. The maxima of the spectra of the copolymers are proportional to the square root of the corresponding retardation times if the spectra are reduced to the corresponding state in which the wedge portions of the spectra coincide with each other.
In the second part, the results by Orioka who polished optical glass pieces by use of the copolymers are semi-quantitatively explained assuming that the surface of the glass polisher is heated by friction up to the temperature at which the shear creep compliance J(t) at t=polishing time is above 10-7cm2/dyn.
A Method of Clearance Regulation in Spark Machining
Authors: Yamaguti Tasaburô , Ishikawa Hideo
Published: November 2005

In the ordinary spark machinings the clearance between a work and a tool electrode cannot be increased without destroying the fineness of the matt-type of the surface finish. In the present spark machining, however, high frequency electric oscillations1) initiated by electric sparks formed between a spark gap break insulations of a thin film of petroleum existing between the electrodes, and thus facilitate the low voltage machining discharges of a definite condenser in a space between the electrodes, the upper limit of the space, that is the clearance, being determined by an adjustment of the spark gap.
The clearance obtained in the surface of lower side of the work electrode increases linearly from 0.043 mm to 0.115 mm with the increase of the spark gap from 0 to 2.2 mm. The roughness of all the finished surfaces is nearly equal and is independent of the clearance. It is discussed that, if we use a modern type machine in the present spark machining method, instead of the present use of a bench drilling machine, the clearance from 0.005 mm to more than 0.1 mm may be obtained keeping the roughness expressed by heights of projections formed on finished surface to a definite value 0.005 mm.
A New Type Spectrometer for Nuclear Magnetic Resonance Dispersion Using Gated Beam Tube
Authors: Nagasawa Hiroshi
Published: November 2005

A new type of nuclear magnetic resonance dispersion spectrometer using a gated beam tube is described. The characteristic feature of this spectrometer is its low noise figure of about three at the comparatively high r.f. level of 4 V. This new spectrometer is much easier to be used than an r.f. bridge because there is no delicate balance adjustment and it is free from any balance drifting. An r.f. amplifier and a detector are no longer necessary because of the amplification and detecting properties of the gated beam tube and it is possible to sweep the frequency simply by sweeping the signal generator. The frequency sweep range is about 200 Kc/sec without any adjustment of the spectrometer.
Elongated Dislocation Loops in Germanium Crystals Deformed in Compression
Authors: Yamashita Tadayoshi
Published: November 2005

The dislocation double trails and elongated loops of edge, 60°, or screw character have been observed in deformed germanium crystals by transmission electron microscopy. The observations of the dislocations were made both on the primary slip plane and on the planes perpendicular to the slip plane. Formation of vacancies during deformation is confirmed from the observed spiral turns of screw dislocations and from the observed climbing of portions of edge dislocations. The formation of screw dislocation trails and loops is explained on the basis of the interaction between 60° dislocations and vacancies.
An Electron Diffraction Unit for Precise Determination of Molecular Structure of Gases
Authors: Shibata Shuzo
Published: November 2005

A new electron diffraction apparatus was designed and constructed for the precise determination of molecular structure of gases. It was devised so as to measure scattering intensities accurately and increase the range of measurement from q=3 up to 230. The apparatus is simple and has a stable optical system, and is efficient and easy to operate. A description of the components of the apparatus is given with a discussion of the use of the apparatus.
Electron and Laser Beam Processing
Authors: Namba Susumu , Kim Pil Hyon
Published: November 2005

Drilling of various materials by electron and laser beams has been studied with the purpose of comparing the two kinds of processing.
The minimum spot obtainable with the electron beam is smaller than that with the laser beam. Hence a smaller hole can be perforated by the electron beam. But, in power efficiency, the laser beam is superior to the electron beam. When the two beams are allowed to impinge upon a metal work-piece, the surface power density of both beams is nearly of the same order, but a higher volume power density can be expected with the laser beam. These results are explained by the characteristics of the two beams.
Optical and Electrical Properties of ZnO Crystals
Authors: Watanabe Hideo , Wada Masanobu , Takahashi Tadashi
Published: November 2005

ZnO crystals thin plate-form were grown from molten lead fluoride. The six-fold c-axis is perpendicular to the planes of the crystals. The transmission in the region of the absorption edge is investigated as a function of temperature. At wavelengths beyond one micron, the absorption coefficient α varies with λ2. The effective mass of (0.06 to 0.14)mis derived from the classical expression for free-carrier absorption. An electron affinity of 1.3 eV is deduced from the photoelectric threshold. The temperature dependence of mobility shows the presence of a large impurity scattering at low temperatures.
An X-Ray Diffraction Study of Precipitated Cadmium Sulphide
Authors: Sato Ryoitiro , Itoh Hikaru , Yamashita Shuji
Published: November 2005

Powders of cadmium sulphide were precipitated with hydrogen sulphide from aqueous solutions of cadmium chloride, bromide, nitrate, and sulphate (and from various mixtures of them) under widely varied concentrations, pH values, and temperatures, and inspected by X-ray diffraction. Hexagonal α-CdS tends to be precipitated from halide solutions, and cubic β-CdS from nitrate and sulphate solutions. Precipitates seem, however, invariably to involve stacking faults of the type proposed in a previous report (R. Sato: Acta Cryst. 15 (1962) 1109). Effects of precipitation conditions on `hexagonality' (fraction of the hexagonal stacking sequence in the crystal) and crystallite-size of products are presented. Attentions are paid to colours of precipitates.
Dark Resistivity of Anthracene Measured by Potentiometric Method
Authors: Hasagawa Katsue
Published: November 2005

Using a potentiometric method, the electrical dark resistivity of anthracene crystals, together with the voltage distributions in the crystals was measured in a range from 80°C up to about 150°C.
The activation energy for dark conduction and ρ0 were found to 0.87 ±0.3 eV independent of the crystal orientation, and to be 2.8×103 Ω-cm in the direction perpendicular to the ab-plane and 6.7×102 Ω-cm in the direction parallel to the abplane, respectively.
When the present results are considered together with previous measurements, the presently available data for the activation energy of anthracene fall into two distinct groups, viz, Group A, with activation energy near 0.9 eV, and Group B, with activation energy near 1.4 eV. A possible interpretation of these values is discussed.
Electrical Properties of Oxidized Si P-N Junctions
Authors: Edagawa Hiroshi , Morita Yoshinori , Ishikawa Hajime , Maekawa Shun-ichi , Inuishi Yoshio
Published: November 2005

The effects of various oxidation methods on the stabilization of the Si surface are discussed.
From the temperature dependence of reverse current, the energy level of the surface trapping centers in thermally oxidized Si p-n junctions is obtained as a range of 0.2 to 0.3 eV from either conduction or valence band.
The n-type conversion on p-type surface due to thermal oxidation which may perhaps correspond to this new level plays important undesirable roles in its stability.
On the converted surface of the oxidized Si p-n junctions, although surface breakdown voltage V

s
approaches on a net bulk breakdown voltage V

B
, the generation of 1/f noise becomes unsatisfactorily predominant. It has been, however, proved that the current fluctuation due to charge transfer between the bulk Si and the slow state is sufficiently avoidable by thick oxide fllm.
According to the measurements of reverse current I

r
and photoresponse, the n-type conversion layer disappears after γ ray irradiation from Co60 and reappears after annealing: another new level may be formed by γ ray.
Furthermore, it has been found that the 1/f noise generated through the oxide fllm in M-O-S (Metal-Oxide-Si) diode is directly proportional to nearly the square of total current I

r
which is not the case in usual p-n junction.
Rheololgical Properties of Asphalt Manufactured from Petroleum Oils of Different Origins
Authors: Kasahara Tetsuo , Hirose Hidenori , Wada Yasaku , Tsuyuki Umeji
Published: November 2005

Torsional creep test and volume dilatometry are carried out for five kinds of straight asphalt manufactured from petroleum oils of different origins. The equilibrium elastic compliance varies from sample to sample and increases very rapidly with increasing number average molecular weight. This is reasonable because the equilibrium complianceJe(∞) is proportional to a higher order average of the molecular weight distribution. This average and henceJe(∞) are almost unchanged through blowing process and depend mostly on chemical compositions of the mineral oil from which the asphalt has been separated.
Excess and Thermal Currents in Gallium Arsenide Esaki Diodes
Authors: Shibata Akikazu
Published: November 2005

The exponential excess current and the thermal current in GaAs Esaki diodes have been studied in the temperature range 77° to 350°K. The exponential excess current is observable in a typical sample up to bias voltages of 1.2 V and 1.4 V at room and liquid nitrogen temperatures, respectively. The existence of an exponential excess current in such a wide bias range requires an almost uniform distribution of intermediate states throughout the energy gap in the vicinity of a junction. The lattice defects of a high concentration should be responsible for the intermediate states. The thermal current in GaAs Esaki diodes is believed to be a high-injection current but not the usual diffusion current.
A Simple Method of Pulse Height Telemetry for a Balloon-Borne Scintillation Counter
Authors: Kajikawa R. , Makino F. , Matsuoka M. , Tanaka Y.
Published: November 2005

A simple method for telemetering the pulse height of a balloon-borne counter is described. Our system consists of a photomultiplier attached to a scintillator, a logarithmic amplifier, a pulse-height-to-time converter and a radio transmitter. The apparatus is operated successfully for a temperature range from -30°C to 30°C and for the pressure less than 10 mmHg.
Kinetische Untersuchung über das Sieden der Flüβigkeit
Authors: Terao Kunio , Hatano Fujio , Sano Fumiaki
Published: November 2005

The time lag of ebullition of water and aceton which were abruptly put in a superheated state was studied statistically in order to obtain the ebullition probaility.
From this ebullition probability and from the time necessary for the development of vapour bubbles, the activation energies for the nucleation and the development of vapour bubbles were calculated.
The activation energy for the nucleation of vapour bubbles is twice as great as that for evaporation on a free surface, whilst the energy for the development of the vapour bubbles is equal to the heat of evaporation. This means that in the process of boiling a vapour bubble is created directly from the liquid itself and not from an air bubble, as was thought previously.
Coloration of Irradiated Sodium-Silicate Glass Containing Impurities
Authors: Sasakura Hiroshi , Takeuchi Nozomu , Miyagi Masakazu , Matsuda Hiromi , Kami Hisao , Nobusawa Torao
Published: November 2005

Au-glass becomes black immediately after the irradiation. It becomes transparent after a subsequent heat treatment at 200°C, and becomes red after a subsequent heat treatment at above 500°C. These changes are attributed to the formation of F-centers, annihilation of F-centers, and formation of colloidal gold respectively. In unirradiated Au-glass, colloidal gold is formed after a heat treatment at above 800°C.
In Mn-glass an absorption band is observed at 540 mµ after the irradiation. It is attributed to the change of the “substitutional” Mn+2 (substituted for Si+4) into Mn+3. On the other hand, the “interstitial” Mn2+ (substituted for Na+) prevents the formation of F-centers, presumably because of the strong interaction between the free electron and Mn+2, which is substituted for Na+. The lack of electrical neutrality of Mn2+ is suggested.
It is shown from ESR experiments that the aggregation of Mn+2 does not occur in glass at room temperature. The experimental results about glasses containing other impurities are also briefly described.
A Modified Fourier Technique in Crystal Structure Analysis
Authors: Watanabé Tokunosuké , Takaki Yoshito
Published: November 2005

A modified Fourier synthesis can be made modifying each of the coefficients by a weight 1-exp
{-b(sin
θ/λ)2}. Characteristic properties of the modified Fourier syntheses are given. It is found that in practice the parameter b ranging from 30 to 10 is useful for structure determination when Cu Kα is used.
An application of this technique to the structure determination of δ-pyrazinamide is given, where this technique is proved to be useful in distinguishing oxygen from nitrogen and nitrogen from carbon. An application to difference synthesis is also discussed.
Microstructures and Recrystallization of Cold-Rolled Single Crystals of Pure Iron
Authors: Taneda Youji
Published: November 2005

The substructures and recrystallization of the cold-rolled iron crystals with different initial orientations have been studied by transmission electron microscopy. When the crystals as-rolled are annealed at increasing temperature, dislocations forming cell structure rearrange to cause subgrains, whose orientations are found among those of the cells, and then recrystallized grains generally appear among the subgrains. The recrystallized grains are exclusively found in the matrix made up of the subgrains having smaller size as well as larger misorientation. There is strong reluctance to recrystallization when most of the segment of the subgrain boundaries consist of dislocation network resulting from the dislocation reaction such as 1/2a[111]+1/2a[1̄1̄1]→a[001]. The subgrain growth due to the coalescence is found from the close examination of the distribution of dislocations in the subgrains. The formation of recrystallization nucleus and the recrystallization tendency are discussed on the basis of the coalescence mechanism.