bluuebunny/crossref_metadata_2025 huggingface dataset:
Nuclear Fusion in Solid
Authors: Wada Nobuhiko , Nishizawa Kunihide
Published: February 2005

Spontaneous neutron emissions were intermittently detected from activated palladium rods well soaked with deuterium gas in a closed glass bulb. By the stimulation of the palladium rods with a high voltage discharge between the rods, a burst of neutron flux 2×104 times larger than background was detected. Atoms or molecules of mass number 1, 2, 3, 4, 5 and 6 were found in the residual gas. Nuclear fusion in solid is interpreted in terms of the supersaturation of the solid solution of deuterium.
Detection of Charged Particles Emitted by Electrolytically Induced Cold Nuclear Fusion
Authors: Taniguchi Ryoichi , Yamamoto Takao , Irie Setsuko
Published: February 2005

We have tried to obtain evidence for electrolytically induced cold nuclear fusion by detecting charged particles associated with the nuclear reaction. Charged particles were detected by a conventional silicon surface barrier detector attached close to the thin foil cathode which formed the bottom of an electrolysis cell. The efficiency and signal-to-noise ratio of this system are higher than those of neutron detection systems, which made it easy to determine whether the fusion occurred or not. The energy spectrum measured with the electrolysis of D2O suggested that the nuclear reaction took place in palladium cathode.
Scanning Tunneling Potentiometry/Spectroscopy (STP/STS)
Authors: Morita Seizo , Maita Yutaka , Takahashi Yoshiaki
Published: February 2005

We constructed a scanning tunneling potentiometry/spectroscopy (STP/STS) system which, for the first time, enables us to simultaneously obtain potential and differential conductance images at various tunneling voltages in addition to the usual topographic image. We applied this STP/STS system to the investigation of a granular surface of a variable carbon resistor. As a result, we found that potential drops at the grain boundary, some grains are conductive while others are resistive, and the grain boundaries are highly resistive in several places.
Correspondence of Three Thermal Adaptation Times in Organisms and the Scaling Law
Authors: Sato Tadashi , Fujimura Jun , Kawashima Yoshikatu , Terao Kunio
Published: February 2005

Comparing the physiological data of man and paramecia, we have found that both of them possess three thermal adaptation times; the continued ratio of the three adaptation times and the generation time of man is nearly equal to the continued ratio of the four times of paramecia. The four characteristic times are scaled to the body weight with the same exponent of 0.28 from bacteria to mammals. This scaling law indicates that the well-known synchronism of times in mammals is extended also to many other organisms.
P-Type Conduction in Mg-Doped GaN Treated with Low-Energy Electron Beam Irradiation (LEEBI)
Authors: Amano Hiroshi , Kito Masahiro , Hiramatsu Kazumasa , Akasaki Isamu
Published: February 2005

Distinct p-type conduction is realized with Mg-doped GaN by the low-energy electron-beam irradiation (LEEBI) treatment, and the properties of the GaN p-n junction LED are reported for the first time. It was found that the LEEBI treatment drastically lowers the resistivity and remarkably enhances the PL efficiency of MOVPE-grown Mg-doped GaN. The Hall effect measurement of this Mg-doped GaN treated with LEEBI at room temperature showed that the hole concentration is ∼2·1016cm-3, the hole mobility is ∼8 cm2/V·s and the resistivity is ∼35 Ω·cm. The p-n junction LED using Mg-doped GaN treated with LEEBI as the p-type material showed strong near-band-edge emission due to the hole injection from the p-layer to the n-layer at room temperature.
Negative Staebler-Wronski Effect in Undoped a-Si:H
Authors: Miyanishi Atsushi , Nakata Jun-ichi , Imao Shozo , Shirafuji Junji , Kubo Uichi , Inuishi Yoshio
Published: February 2005

A new finding of the “negative Staebler-wronski (NSW) effect” in the photoconductivity of undoped a-Si:H is described. The photoconductivity of a-Si:H deposited at low substrate temperature T
s (150°C) increased again beyond the initial value after a decrease due to the “normal SW effect” by prolonged light soaking at relatively high temperature (≧40°C). Little NSW effect was observed in the films deposited at higher T
s. This effect is speculated to be caused by the microscopic reconstruction of the a-Si:H network due to the cooperation of nonradiative recombination of photocarriers and thermal energy.
The Role of Self-Trapped Holes in the Photoercation of Dangling Bonds in a-Si:H
Authors: Morigaki Kazuo
Published: February 2005

We consider the creation of dangling bonds by low-temperature illumination in a-Si:H. It is found that self-trapping of holes in weak bonds adjacent to Si:H bonds plays an important role in the photocreation of dangling bonds.
Preparation of Superconducting Bi-Sr-Ca-Cu-O Films by Plasma-Assisted Organometallic Chemical Vapor Deposition
Authors: Kobayashi Kenkichiro , Ichikawa Satoshi , Okada Genji
Published: February 2005

The Bi2Sr2CuO
x
and Bi2Sr2CaCu2O
x
films are prepared on single-crystalline SrTiO3 (100) at 650°C by the plasma assisted organometallic chemical vapor deposition method. There are only (00l) reflections in the X-ray diffraction patterns of these films. This indicates that the c axes of these films are oriented preferentially perpendicular to the substrate surface. The Bi2Sr2CaCu2O
x
films prepared in 1 Pa are semiconductive, while the films prepared in 100 Pa exhibit onset T
c at 63 K.
Magnetic Properties of the High-TcSuperconductor Tl0.5Pb0.5Ca0.8Er0.2Sr2Cu2Oxide
Authors: Liu R. S. , Edwards P. P. , Janes R. , Watson-yang T. J. , Wu P. T.
Published: February 2005

The magnetic properties of the monophasic superconductor Tl0.5Pb0.5Ca0.8Er0.2Sr2Cu2Oywith a TlCaBa2Cu2O7-type (1122) structure have been studied using a combination of magnetisation and ESR (Electron Spin Resonance) measurements. This new material exhibits a superconductive transition (Tc) around 110 K, above which the temperature dependence of the magnetic susceptibility can be described by a Curie-Weiss law. BelowTcthe co-existence of superconductivity and paramagnetism was observed.
Preparation of Superconducting Bi-Pb-Sr-Ca-Cu-O Glass Ceramics with Tc,zero=106 K
Authors: Yamanaka Hiroshi , Matsuda Motohide , Takata Masasuke , Ishii Mamoru , Yamashita Tsutomu , Koinuma Hideomi
Published: February 2005

Superconducting Bi-Pb-Sr-Ca-Cu-O glass ceramics were prepared by the melt quenching method. The T
c,onset and T
c,zero of the sample annealed at 845°C for 24 h in air were 115 K and 106 K, respectively. From the results of X-ray diffraction and SEM observation, it was inferred that the c-axis was oriented in parallel with the surface of the annealed sample.
Superconductivity in Tl-Bi-Ca-Sr-Cu-O and Tl-Bi-Pb-Ca-Sr-Cu-O Systems
Authors: Torii Yasuko , Takei Hiromi , Tada Kouji
Published: February 2005

The influence of the substitution of Bi for Tl on the formation of the superconducting phases in Tl-Bi-Ca-Sr-Cu-O and Tl-Bi-Pb-Ca-Sr-Cu-O systems was investigated. The superconducting (Tl, Bi)Ca2Sr2Cu3O9 phase with critical temperature of 113 K showing both zero resistivity and diamagnetism is prepared in a Tl-Bi-Ca-Sr-Cu-O system. The crystal structure of this phase is tetragonally symmetric with lattice constants of a=3.813(3) Å and c=15.266(5) Å. The superconducting tetragonal phase of (Tl, Bi, Pb)Ca2Sr2Cu3O9 is also formed in a Tl-Bi-Pb-Ca-Sr-Cu-O system.
Preparation of Bi1.5SrCaCu2Ox Glass Fibers Using Melt-Quenched Glasses
Authors: Onishi Masashi , Kohgo Takashi , Chigusa Yoshiki , Kyoto Michihisa , Watanabe Minoru
Published: February 2005

Bi1.5SrCaCu2O
x
glass preforms were prepared by the melt-quenching method, and their thermal characteristics and viscosity were investigated to determine the possibility of drawing them into glass fibers. Furthermore, Bi1.5SrCaCu2O
x
glass fibers were drawn from glass preforms by the method that is ordinarily applied to optical fiber fabrication. The drawn fibers were very flexible, and the maximum length was 1200 mm.
Application of Excimer Laser Polymer Ablation to Alignment of Liquid Crystals: Periodic Microstructure on Polyethersulfone
Authors: Niino Hiroyuki , Kawabata Yasujiro , Yabe Akira
Published: February 2005

In view of applications for excimer laser ablation, it was found that the highly periodic microstructure on polyethersulfone, which was produced by XeCl excimer laser ablation, was effective for alignment of nematic liquid crystals. The alignment of the liquid crystal molecule depends on the orientation of the microstructure, which is easily controlled.
New Process for Fluoride Glass Preform Fabrication Using Chemical Vapor Deposition
Authors: Fujiura Kazuo , Ohishi Yasutake , Takahashi Shiro
Published: February 2005

A new process for ZrF4-based fluoride glass preform fabrication is proposed. For the first time, ZrF4-based fluoride glass soot (ZrF4-BaF2-LaF3-AIF3) has been prepared by CVD using metal β-diketonates and hydrogen fluoride gas as starting materials and fluorinating reagent, respectively. The fluoride glass soot has been consolidated into a transparent glass layer with residual closed pores. The new process using CVD is applicable to the preparation of fluoride glass preforms. It is promising for the realization of ultra-low loss and long-length optical fibers.
Pyroelectricity in Poled Thin Films of Aromatic Polyurea Prepared by Vapor Deposition Polymerization
Authors: Takahashi Yoshikazu , Iijima Masayuki , Fukada Eiichi
Published: February 2005

Aromatic polyurea films with a thickness of less than 1 µm were prepared by vapor deposition polymerization using different kinds of aromatic diamine and diisocyanate monomers. After poling above the glass transition temperature, the films acquired a pyroelectric activity of (1.0–2.5)×10-5 C/m2K, which is comparable to that of polyvinylidene fluoride. The temperature limit for the activity was 150 to 200°C, depending on the kind of monomer. The multilayer films consisting of aromatic polyurea and aluminum electrodes showed a high sensitivity proportional to the number of layers.
Theory of Screening-Enhanced D-D Fusion in Metals
Authors: Vaidya S. N. , Mayya Y. S.
Published: February 2005

The enhancement in d-d fusion rates in metals brought about by the combined screening of electrostatic interactions by the conduction electrons and mobile deuterons, is investigated using the jellium model. It is assumed that under electrolytic conditions, deuterium exists as itinerant deuterons in metals such as palladium. We derive an expression for the screening constant treating electrons as fermions and deuterons as bosons. The screening by charged bosons is a novel concept and is found to be sensitively dependent upon the temperature. The d-d fusion rate is found to increase substantially when the electron-deuteron screening of the Coulomb barrier is incorporated.
Observation of Potential and Diamagnetism in a Mirror Plasma with Electron Beam Injection
Authors: Ishii Kameo , Inami Hiroshi , Kawabe Takaya
Published: February 2005

An electron beam with an energy of ∼9 keV and a current of ∼6 A was injected into a mirror-trapped plasma at various angles up to ∼20°, which is a loss-cone angle, along the magnetic field line from one end. The 20° oblique injection effectively induces diamagnetism at the mirror cell as compared with the parallel injection, but the potential is insensitive to the injection angle. The electron beam oblique injection is useful in forming a thermal barrier with ECRH.
Dependence of the Nonresonant Laser Ionization of Rare Gases on Laser Wavelength
Authors: Kokubun Kiyohide , Ichimura Shingo , Hashizume Hiroko , Shimizu Hajime , Oowadano Yoshiro , Matsumoto Yuji , Endo Kazuhiro
Published: February 2005

The nonresonant multiphoton ionization of rare gases has been studied by means of XeCl, KrF and ArF excimer lasers. In the course of this study, it was observed that in the cases of the XeCl and KrF lasers, the ionization intensities of Xe gas were stronger than those of Kr gas, but in the case of the ArF laser, the former was weaker than the latter. This result is interpreted as an effect of laser wavelength.
Physical Models for Deep Submicron Device Simulation
Authors: Sonoda Ken'ichiro , Inoue Yoshitsugu , Taniguchi Kenji , Hamaguchi Chihiro
Published: February 2005

An impact ionization model is derived for silicon with anisotropic and nonparabolic band structure. The validity of the model is verified by comparing calculated and experimental results on both impact ionization coefficient and quantum yield. A phenomenological length constant for the extended drift-diffusion model is evaluated using an iterative method based on the Boltzmann transport equation. The length constant increases with applied electric field at low field and flattens out above 30 kV/cm, reaching a saturation value of 400 Å.
KrF Excimer Laser Irradiation Effect on GaAs Atomic Layer Epitaxy
Authors: Ishikawa Hironori , Kawakyu Yoshito , Sasaki Masahiro , Mashita Masao
Published: February 2005

The KrF excimer laser irradiation effect on GaAs ALE was investigated by the surface process model. It was confirmed that the decomposition rate of TMG adsorbed on the surface As atoms was increased, and its activation energy was decreased due to KrF excimer laser irradiation. In selective growth using substrates partially masked with SiO2, it was found that a large amount of TMG molecules diffused to the GaAs surface from the SiO2 mask in a low temperature range, but very few TMG molecules diffused to the GaAs surface from the SiO2 mask in a high temperature range.
Magnetic Relaxation in High-Tc Oxide Superconductors
Authors: Kumakura Hiroaki , Togano Kazumasa , Yanagisawa Eiji , Takahashi Kazuhiko , Nakao Masao , Maeda Hiroshi
Published: February 2005

Magnetic relaxation was measured at 77 K for Bi-Sr-Ca-Cu-O, Tl-Ba-Ca-Cu-O and Y-Ba-Cu-O polycrystalline oxides in order to investigate thermally activated flux creep. The magnetic relaxation for Bi- and Tl-based bulk samples was larger than that for the Y-based samples. The magnetic relaxation for Bi-based samples was greatly decreased by powdering, which indicates that the large relaxation of the bulk samples is not an intrinsic property but is due to large flux creep at grain boundaries. The activation energy related to the flux-pinning was 0.13 and 0.19 eV for Bi-Sr-Ca-Cu-O and Y-Ba-Cu-O compounds, respectively.
Relation of Tc with Hole Concentration in Ln1+xBa2-xCu3O7-δ (Ln=Sm and Eu); Hall Effect Measurement and Chemical Analysis
Authors: Akinaga Hiroyuki , Katoh Hideo , Takita Kôki , Masuda Kohzoh
Published: February 2005

Hole concentration is investigated in single-phase samples of Ln1+x
Ba2-x
Cu3O7-δ (Ln=Sm and Eu) by two different methods: Hall effect measurement and iodometric titration. For both systems, the temperature dependence and x dependence of the effective hole concentration p
H (=1/R
H
e) deduced from the Hall coefficient R
H show behaviors very similar to those in Nd1+x
Ba2-x
Cu3O7-δ, which were reported previously. The superconductivity transition temperature T
c shows a simple relation to p
H deduced from R
H just above T
c, which is almost the same as that of the Nd-system. The hole concentration in a CuO2 sheet estimated from the chemical analysis yields almost the same value for p
H, at least for samples with T
c's lower than 70∼80 K. Thus, the relation of T
c with hole concentration is essentially the same for three different compound systems Ln1+x
Ba2-x
Cu3O7-δ (Ln=Nd, Sm and Eu). This indicates that the superconducting T
c is determined uniquely by the hole concentration in a CuO2 sheet, and that high-T
c superconductivity is not affected by the value of the magnetic moment at the Ba site.
Epitaxial Lateral Overgrowth of GaAs on a Si Substrate
Authors: Ujiie Yoshinori , Nishinaga Tatau
Published: February 2005

Epitaxial lateral overgrowth (ELO) of GaAs on a Si substrate was successfully achieved by a combination of LPE and MBE. To prevent meltback of the Si substrate by Ga solution, a thin GaAs layer (2.4 µm) was grown by MBE prior to the deposition of SiO2 by P-CVD. Uniform GaAs ELO layers with mirror surface were grown through a line-shaped window cut in SiO2 film on a Si substrate with a GaAs layer. Chemical etching with an RC-1 etchant showed that there were no etch pits observed in ELO layers except in the region just over the line seed. Although cracks are observed in ELO layers due to the difference in thermal expansion coefficients between GaAs and Si, it is concluded that this technique is promising for obtaining dislocation- free GaAs on a Si substrate.
Studies on an (NH4)2Sx-Treated GaAs Surface Using AES, LEELS and RHEED
Authors: Oigawa Haruhiro , Fan Jia-Fa , Nannichi Yasuo , Ando Koji , Saiki Koichiro , Koma Atsushi
Published: February 2005

Surface properties of (NH4)2S
x
-treated GaAs (100), (111)Ga and (1̄1̄1̄)As planes were studied by means of Auger electron spectroscopy (AES), low-energy electron energy loss spectroscopy (LEELS) and reflection high-energy electron diffraction (RHEED). We found that oxide-free and sulfur-terminated GaAs surfaces produced by the (NH4)2S
x
treatment provided the reduction of interface state density. Furthermore, comparison of various planes revealed that (i) sulfur atoms could combine with both Ga and As and (ii) bonding between Ga and S was stronger than that between As and S.
Fabrication of a-Si:H Thin Films Using a Microwave Discharge Under a Magnetic Field of Electron Cyclotron Resonance
Authors: Kato Kiyotaka , Kato Isamu
Published: February 2005

We have fabricated a-Si:H thin films using a microwave discharge under a magnetic field of electron cyclotron resonance (ECR). The films fabricated in ECR plasma are predominantly Si-H bonded because of high-energy plasma particle bombardment. The films fabricated on glass substrates, however, peel off easily because of the difference in the coefficient of heat expansion between the film and the substrate. The films fabricated out of ECR plasma are not subjected to the bombardment and are mainly Si-H2 bonded. These films do not peel off even when deposited on glass substrate and are of high quality.
TILBW Bipolar Power Switching Transistor
Authors: Silard Andrei P. , Nani Gabriel
Published: February 2005

The work reports the development of TILBW (Two Interdigitation Levels with heavily-doped Base Wells) bipolar power switching transistors, which combine the main advantages of both TIL and GAT devices. The TILBW transistors exhibit the following many-fold advantages in comparison with identical, yet conventional devices of the same class (identical area and case) processed simultaneously: a reduction of the turn-on time by a factor of ∼20; a two-fold reduction of the fall time t
f; an ∼18-percent increase of V
CEO(SUS) an ∼23-percent increase of V
CBO; an enhanced RBSOA.
Influence of Cooling Rate on Superconducting Characteristics of Bi-Pb-Sr-Ca-Cu-O Ceramics
Authors: Kikuchi Akira , Matsuda Motohide , Takata Masasuke , Ishii Mamoru , Yamashita Tsutomu , Koinuma Hideomi
Published: February 2005

The influence of the cooling rate on superconducting characteristics was investigated for Bi-Pb-Sr-Ca-Cu-O ceramics. It was found that the critical temperature T
c,zero and the critical current density J
c at 77 K were strongly dependent on the cooling condition. The optimum cooling condition to maximize T
c,zero and J
c was in the range from about 50°C/h to 100°C/h.
High-Pressure Synthesis of a Bi-Pb-Sr-Ca-Cu-O Superconductor
Authors: Enami Hiroyoshi , Kawahara Nobuaki , Shinohara Toshiyuki , Kawabata Sanemasa , Hoshizaki Hiroki , Matsumuro Akihito , Imura Toru
Published: February 2005

Nearly perfect high-T
c single-phase powder of Bi-Pb-Sr-Ca-Cu-O was prepared by a modified solid-phase reaction method. This powder was then synthesized under 5.4 GPa to form a high-density block. While the pressed sample exhibited semiconducting behaviour, the post annealed sample showed a superconducting transition with T
c,onset=113 K, T
c,end=105 K and J
c (at 77 K)=508 A/cm2.
Preparation and Chemical Composition of Superconducting Oxide Tl2Ba2Can-1CunO2n+4 with n=1, 2 and 3
Authors: Kikuchi Masae , Kajitani Tsuyoshi , Suzuki Teruo , Nakajima Satoru , Hiraga Kenji , Kobayashi Norio , Iwasaki Hideo , Syono Yasuhiko , Muto Yoshio
Published: February 2005

Superconducting oxides of Tl2Ba2Ca
n-1Cu
n
O2n+4 with n=1, 2 and 3 were synthesized, and their structure and chemical composition were examined by X-ray powder diffraction, EPMA, Rietveld analysis and electron microscopy. Partial substitution of Tl with Ca was confirmed, but the production of holes in Cu layers expected from this substitution was rather small for a 120 K superconductor. Charge transfer of Tl3-δ-Cu2+δ would provide both the hole in the Cu-O bond required for high T
c and s-like electron of Tl atoms for stabilization of layered structures.
Reversible Phase Transition of the Bi-Ca-Sr-Cu-O System between Semiconductivity and Superconductivity
Authors: Liu R. S. , Huang Y. T. , Jiang J. M. , Wu P. T. , Chang C. T.
Published: February 2005

Alternative quenching from higher temperature with liq. nitrogen and annealing at lower temperature exhibit a reversible phase transition from semiconductivity to superconductivity in the Bi-Ca-Sr-Cu-O system. The thermally treated specimens were characterized by means of X-ray diffraction (XRD). The specimens quenched from above 900°C were found to be semiconducting, and were converted into superconducting after being annealed at 820°C for 40h under O2 atmosphere. The annealed samples had two norminal compositions corresponding to Tc,onset=150K and Tc,zero=90K for BiCaSrCu2O
x
and Tc,onset=125K and Tc,zero=84K for Bi4Ca3Sr3Cu4O
x
.
Vapor Phase Epitaxy of AlGaAs by Direct Reaction between AlCl3, GaCl3 and AsH3/H2
Authors: Yamaguchi Hiromu , Kobayashi Ryuji , Jin Yoshito , Hasegawa Fumio
Published: February 2005

AlAs and AlGaAs were successfully grown by a directly reacting of AlCl3, GaCl3 and AsH3 for the first time. The AlCl3 and GaCl3 were contained in stainless steel evaporators (60°C–120°C), and supplied by He carrier gas. The AsH3 (10% in H2) was supplied directly to the deposition zone by H2 carrier gas during the growth. The AlAs layers could be grown in the temperature range from 550°C–700°C, and a maximum growth rate of 3.5 µm/h was obtained. The AlGaAs was grown at 600°C, with a typical growth rate of about 2 µm/h. The Al content was controlled in the entire composition range but was not linearly proportional to the Al content in the supplied gas. These results suggest the possibility of new carbon-free gas sources for the chemical beam epitaxy (CBE) and atomic layer epitaxy (ALE).
Synthesis of High-Tc YBa2Cu3O7-x Superconductors at a Low Annealing Temperature from a Glass Precursor
Authors: Koo H. S. , Tseng T. Y. , Liu R. S. , Huang Y. T. , Kuan K. S. , Wu P. T.
Published: February 2005

High-T
c superconducting YBa2Cu3O7-x
oxides prepared at a low annealing temperature (850°C) from a glass precursor by rapid quenching from the melt have been successfully obtained with zero resistivity at the temperature of 92 K. The kinetics of the phase transition from the glassy state to superconducting phase have been characterized by differential thermal analysis, X-ray diffraction and scanning electron microscopy. The magentic properties of the YBa2Cu3O7-x
samples were measured by dc SQUID magnetometer are also discussed.
Dynamic Luminescence Spectroscopic Study on Laser Ablation of Bi-Sr-Ca-Cu Oxide Superconducting Materials
Authors: Fukumura Hiroshi , Nakaminami Hiroshi , Eura Shigeru , Masuhara Hiroshi , Kawai Tomoji
Published: February 2005

Time-resolved luminescence spectra obtained upon a UV-laser ablation of Bi-Sr-Ca-Cu-O superconducting materials were measured with nanosecond time resolution. In the early delay times after the irradiation, a wide continuum spectrum with self-absorption lines due to the electronic transitions from the ground states of Ca+, Sr+, and Sr was observed. The continuum emission decayed with the lifetime of 70 ns and was replaced by emission lines of Ca+, Sr+, Ca and Sr which had decay times of around 1 µs.
Magnetic Aftereffects in High Tc Superconducting Thin Films
Authors: Hatta Shin-ichiro , Ichikawa Yo , Adachi Hideaki , Wasa Kiyotaka
Published: February 2005

In superconducting oxide films, strong magnetic aftereffects are observed. They are considered to be due to creep of trapped magnetic fluxoids. The aftereffects reveal the logarithmic time dependence. For TlBaCaCuO film, an activation energy of the effects can be estimated to be 0.03 eV in an external field of 100 Oe.
Dependence of Superconducting Properties on Substrate Temperature in Y-Ba-Cu-O Thin Films Prepared by Magnetron Sputtering
Authors: Michikami Osamu , Asahi Masayoshi , Asano Hidefumi
Published: February 2005

Y-Ba-Cu-O thin films (1500–2000Å) are prepared on MgO (001) substrates at 450°C to 680°C by RF magnetron sputtering. At substrate temperatures of 580°C and above, as-grown superconducting films with high c-axis orientation, end-point Tc above 80 K and a smooth surface are obtained. As the substrate temperature decreases below 580°C, transition temperature and diffraction intensity are rapidly reduced, as is the formation of c-axis-oriented crystals with different lattice parameters.
Multichannel DC SQUID System
Authors: Furukawa Hisao , Shirae Kimisuke
Published: February 2005

A new essential multichannel dc SQUID system has been devised. The system consists of two stages of dc SQUIDs; in the first stage, a number of dc SQUIDs equivalent to the input number detect the input signals, and the sum of the first-stage output modulates the carrier of the second-stage dc SQUID and is sent by the carrier to a room temperature amplifier, where the mixed input signals are separated into the original signals. To verify the system operation, a three channel dc SQUID system has been developed and good results have been obtained.
X-Ray Detection with Nb/AlOx/Nb Superconductor Detectors
Authors: Kurakado Masahiko , Matsumura Atsuki
Published: February 2005

We have detected 5.9 keV X-rays with Nb/AlO
x
/Nb superconducting tunnel junctions which are resistant to thermal cycling. Using an anodization method to fabricate the junctions, X-ray signals could be detected. We propose an experimental method to determine the fundamental limit of energy resolution which comes from the statistical fluctuation of signal charges. The limit obtained for one of our samples was smaller than 135 eV for 5.9 keV radiation.
Possibility of a High-Efficiency Pulsed Vibrational Overtone HF Chemical Laser
Authors: Ashidate Shu-ichi , Obara Minoru
Published: February 2005

We have theoretically analyzed the possibility of a high-efficiency frequency conversion using first vibrational overtone transitions in a discharge-initiated nonchain (H2/SF6) HF chemical laser. In a pulsed operation, vibrational overtone HF laser energy can be obtained with a high conversion efficiency of 67% of the fundamental output energy by suppressing fundamental transitions perfectly. A multiline oscillation of 1.3–1.5 µm in wavelength is expected in the first vibrational overtone transitions. An overtone laser energy density of 0.87 mJ/cm3 is achievable from a discharge-initiated, He-diluted gas mixture of SF6/H2/He=84/12/404–664 (Torr).
Two-Wavelength Displacement-Measuring Interferometer Using Second-Harmonic Light to Eliminate Air-Turbulence-Induced Errors
Authors: Ishida Akira
Published: February 2005

In order to eliminate air-turbulence-induced errors in the measurement of linear displacement, an interferometer with two different laser beams using second harmonic generation (SHG) has been developed. These beams have wavelengths of 488 nm, emitted from an Ar+ laser, and 244 nm, which is the second harmonic generated by a nonlinear crystal β-BaB2O4 inserted in the Ar+ laser cavity. Demonstration experiments have proven the system's efficacy in eliminating air-turbulence-induced errors.
Poly(3-alkylthiophene) Gel and Its Properties
Authors: Yoshino Katsumi , Nakao Kenji , Sugimoto Ryu-ichi
Published: February 2005

Conducting polymer gels have been prepared with poly(3-alkylthiophene)s of alkyl chain length n shorter than 12. Drastic volume change of the polymer gel was observed upon changing the concentration of ethanol in chloroform and also upon changing the temperature. The absorption spectrum also changed drastically in association with the volume change. These conducting polymer gels can also be doped.
An Arrangement of Boundary Dislocations in White Tin Observed by High-Resolution Electron Microscopy
Authors: Ojima Kozo , Taneda Youji
Published: February 2005

The core structures of end-on dislocations at a low angle tilt boundary in white tin have been observed using high-resolution electron microscopy (HREM). HREM observation shows that the tilt boundary is constructed by alternate arrangements of a 1/2<111 > perfect dislocation and two 1/2<010 > imperfect dislocations.
A Few Techniques for Preparing Conductive Material Films for Sputtering-Type Electron Cyclotron Resonance Microwave Plasma
Authors: Matsuoka Morito , Ono Ken'ichi
Published: February 2005

A few techniques are developed for preparing conductive material films for sputtering type electron cyclotron resonance microwave plasma. Microwave pressure window contamination, which is the most serious obstacle to conductive film preparation, can be avoided by using a vacuum microwave guide. Dense plasmas of 1011 cm-3 are obtained at a gas pressure of 10-2 Pa, and several metal films, including Al, Mo, Cu, and Fe films, are continuously deposited. Much denser plasmas of 1012 cm-3 are generated by high rate sputtering apparatus with an electric mirror, and films are deposited at rates of over 2000Å/min.
P-Type Conduction in ZnS Grown by Vapor Phase Epitaxy
Authors: Iida Seishi , Yatabe Toshie , Kinto Hitoshi
Published: February 2005

Low-resistivity p-type ZnS layers have been grown on GaAs substrates by vapor-phase epitaxy from a Zn-added ZnS powder source, using an open tube system under a NH3-added hydrogen flow. The simultaneous addition of NH3 and Zn has been shown to be essential for the appearance of p-type conduction. The room temperature Hall-effect measurement of a grown layer revealed the hole concentration to be 6×1018 cm-3 and the mobility to be 40 cm2/(V·s). The p-ZnS/n-GaAs heterojunction showed good rectifying behavior and exhibited an infrared emission, having a peak photon energy corresponding to the band gap energy of GaAs under forward bias.
pnp-Type GaAs Inversion-Base Bipolar Transistor (pnp-type GaAs IBT)
Authors: Matsumoto Kazuhiko , Hayashi Yutaka , Kojima Takeshi , Yoshimoto Tomomi , Nagata Toshiyuki
Published: February 2005

A pnp-type GaAs inversion-base bipolar transistor was fabricated for the first time. The common emitter current gain obtained was β=1010 at 77 K. By measuring the FET mode operation of the GaAs IBT, it was confirmed that the two-dimensional electron gas really worked as a base of the transistor.
Interface States in n-ZnSe/n-GaAs Heterostructure Characterized by Deep Level Transient Spectroscopy Technique
Authors: Matsumoto Takashi , Ito Yuuji , Ishida Tetsuro
Published: February 2005

The n-ZnSe epitaxial layer/n-GaAs substrate heterointerface grown by low-pressure vapor phase epitaxy has been investigated by the deep level transient spectroscopy technique. New electron emissions have been observed near the n-ZnSe/n-GaAs heterointerface. The electronic states giving rise to the electron emission had an activation energy of 0.6∼0.9 eV. Bulk deep levels were detected in n-ZnSe and n-GaAs in regions away from the heterointerface.
Superconducting Properties of Grain-Oriented Samples of Y1Ba2Cu3Oy
Authors: Nakagawa Yoshihiko , Yamasaki Hirofumi , Obara Haruhiko , Kimura Yoichi
Published: February 2005

Highly oriented Y1Ba2Cu3O
y
(YBCO) bulk samples more than 2 cm3 in volume have been prepared by a field-induced orientation method. The ratio of the resistivity along the c axis to that in the a
b plane at a room temperature was about six. The critical current density J
c was larger in the a
b plane than along the c axis. In the case of current I//a
b plane, it was larger for field H//a
b plane than for H//c axis. From the J
c-H property and the growth morphology of the samples, the possibility of grain boundary pinning in the YBCO superconductors has been discussed.
Dopant Effects on the Superconductivity in the Bi-Sr-Ca-Cu-O System
Authors: Kanai Tsuneyuki , Kamo Tomoichi , Matsuda Shin-pei
Published: February 2005

The effects of 34 different dopants on the BiSrCaCu2O
y
ceramics were investigated. The dopants can be classified into four categories depending on their solubilities and substitutional properties in the Bi-Sr-Ca-Cu-O structure. Dopants in the first group, i.e. Fe, Co, Ni and Zn, dissolve and substitute into the copper site and can significantly reduce the transition temperatures (T
c's) of the high- and low-T
c phases. The second group of dopants, i.e. rare-earth elements, substitute into the Ca sites and cause the disappearance of the high-T
c phase and increase the T
c's in the low-T
c phase. The dopants in the third group, i.e. alkaline metals and phosphorus, have a strong tendency to decompose the superconducting phase. The remainder of the dopants investigated were classified as the fourth group. Superconductivity of the high- and low-T
c phase of the fourth group remains almost uneffected.
Weak Field Breakdown of Superconductivity in Ceramic YBa2Cu3O7-x
Authors: Yamada Yasuji , Morimoto Takeshi , Suzuki Mitsuru
Published: February 2005

The critical current of ceramic YBa2Cu3O7-x
samples with a variety of cross-sectional areas were measured at 77 K and the critical magnetic field at the surface of the samples was estimated to be about 10 Oe. The remarkable diamagnetic response corresponding to the weak field breakdown of superconductivity was observed for the first time.
Raman Scattering Study of the Effect of Nd Substitution into Ba Sites on the Phonon Spectrum of Nd1+xBa2-xCu3Oy (x=0–0.4, y=∼7)
Authors: Nishitani Ryusuke , Yoshida Naoki , Sasaki Yoshiro , Nishina Yuichiro
Published: February 2005

We have carried out a study of the effect of trivalent Nd ion substitution into the divalent Ba site on the Raman spectra of Nd1+x
Ba2-x
Cu3O
y
(x=0–0.4, y=∼7) as a function of x. A systematic change occurs in the phonon band from 500 through 600 cm-1 which is related to the oxygen vibration in the BaO or CuO layer. The mode near 310 cm-1, which has been attributed to Cu(2)-O(2, 3) bending vibrations in the CuO2 layer, does not show substantial variation with an increase in x. These results are discussed in connection with the orbital character of the hole.
Study on the Preparation and the Physical Properties of a 110 K (Bi, Pb)2Sr2Ca2Cu3Oy Superconductor
Authors: Maeda Atsutaka , Noda Kazuyoshi , Uchinokura Kunimitsu , Tanaka Shoji
Published: February 2005

High-quality samples of 110 K superconductor (Bi, Pb)2Sr2Ca2Cu3O
y
were prepared in a single-phase polycrystalline form, which show resistivity at room temperature below 1 mΩ·cm and a zero-resistance temperature of 107 K. The Hall coefficient and the plasma frequency were measured in these crystals. The Hall coefficient and the plasma frequency obtained were 1×10-3 cm3/C and 8700 cm-1, respectively.
Critical Current Characteristics of YBa2Cu3O7-x-Ag Composite
Authors: Imanaka Nobuhito , Saito Fumihiko , Imai Hisao , Adachi Gin-ya
Published: February 2005

Silver powder was mixed with a Y-Ba-Cu-O superconductor so as to improve its critical current density, J
c. The J
c of YBa2Cu3O7-x
with silver (3 wt%) was twice that without silver. T
c (end point) was almost constant around 90 K in spite of the silver mix. The decrease of T
c (end point) with magnetic flux was greatly inhibited by the silver mixing.
Synthesis Process of the High Tc Superconductor in the Tl2Ca2Ba2Cu3Ox Phase
Authors: Wang C. , Chang H. L. , Chu M. L. , Gou Y. S. , Uen T. M.
Published: February 2005

High T
c superconductor Tl2Ca2Ba2Cu3O
x
were prepared by a two-stage process: prequenched after a 880°C×12 minutes heat treatment, and then annealed at 880–890°C for 120 minutes in a flowing oxygen atmosphere. The zero-resistivity temperatures distribute in a range from 115 to 119 K. The X-ray diffraction patterns exhibit that they are all in the 2223 phase. The results indicate that the predominance of Tl2Ca2Ba2Cu3O
x
phase is irrelevant to whether the composition of the starting material is TlCa3BaCu3O
x
or Tl2Ca2Ba2Cu3O
x
by using our process. The influence of each stage in our process has also been studied.
Properties of Pb-Doped Bi-Sr-Ca-Cu-O Superconductors Prepared by the Intermediate Pressing Process
Authors: Asano Toshihisa , Tanaka Yoshiaki , Fukutomi Masao , Jikihara Kazunori , Maeda Hiroshi
Published: February 2005

Effects of an intermediate press process on the microstructure and superconducting properties of the Pb-doped Bi-Sr-Ca-Cu-O system have been studied. Samples were made by sintering uniaxially pressed pellets after the conventional pellet-sintering process. Highly textured microstructure with strong (001) reflections was confirmed by X-ray diffraction and SEM. A short sintering time was sufficient to form only the high-T
c phase. By this intermediate pressing and sintering process, J
c was much increased and the magnetic field dependence of J
c was also improved. The highest J
c achieved was 3560 A/cm2 at 0 T and 77.3 K.
Ba3Y2Cu2PtO10: Newly Obtained Phase During Single Crystal Growth of Ba2YCu3O7-δ from Platinum Crucible
Authors: Hibiya Taketoshi , Nakabayashi Yukinobu , Satoh Tetsuro , Kawamura Tsutomu
Published: February 2005

A new compound whose chemical composition is Ba3Y2Cu2PtO10 was obtained as a single crystal during preparation of Ba2YCu3O7-δ single crystals from CuO fluxed melt using a platinum crucible. The compound has monoclinic symmetry (space group: C2/m); its lattice parameters are a
0=12.333 Å, b
0=5.751 Å and c
0=7.247 Å, and β=105°40'. As-grown crystal is insulating or semiconducting, and has a room temperature resistivity of 3 MΩcm.
High-Tc Superconducting Films of Bi-Pb-Sr-Ca-Cu Oxide Prepared by Plasma Spraying
Authors: Yoshida Yuji , Kitahara Shigeru , Togano Kazumasa , Yuyama Michinari , Inoue Kiyoshi , Maeda Hiroshi , Funaki Minoru
Published: February 2005

Superconducting properties and microstructures of the Bi-Pb-Sr-Ca-Cu oxide films prepared by plasma spraying have been studied. Films with a thickness of about 150 µm have been prepared from Bi1.52Pb0.48Sr1.66Ca1.18Cu2.31O
x
powders. The as-sprayed films, deposited on nickel substrate, are amorphous and not superconductive. After annealing in air at 840°C the films exhibit a zero-resistance temperature of 107 K (zero field) with a transition width of about 11 K.
Formation of High-Tc 110 K Superconducting Phase at the PbO/Bi2Sr2Ca4Cu6Oy Interfaces
Authors: Hakuraku Yoshinori , Kittaka Kazuhiro , Higo Satoru , Ogushi Tetsuya
Published: February 2005

Reaction and intermixing at the PbO/Bi2Sr2Ca4Cu6O
y
interfaces led to the formation of a high-T
c superconducting Phase of Bi-Sr-Ca-Cu-O with a superconducting onset at about 110 K. Samples have been prepared by a solid state reaction in air. Samples, heat treated at about 845°C for 50–150 h, showed zero resistivity above 100 K. Both the ac susceptibility measurements and the X-ray powder diffraction revealed the high-T
c phase. A sample without the interfaces did not become superconducting above 77 K after the same heat treatment. Although the superconducting properties of the samples were quite sensitive to the heating conditions, the growth of the high-T
c phase was clearly promoted by the presence of the interfaces.
Novel Doping Effect of Conducting Polymer Gel
Authors: Yoshino Katsumi , Nakao Kenji , Onoda Mitsuyoshi , Sugimoto Ryu-ichi
Published: February 2005

The volume of conducting poly(3-alkylthiophene) gel shrinks drastically upon doping and recovers upon undoping. With decreasing temperature below some threshold, the volume of undoped poly(3-alkylthiophene) get decreases remarkably but the change in the volume of doped gel is nearly negligible. The color of poly(3-alkylthiophene) gel changes from yellow in the undoped expanded state to red in the undoped shrunken state and also to black in the doped shrunken state. The conductivity of poly(3-alkylthiophene) gel reaches about 10-1 S/cm upon iodine doping. This enhancement of conductivity is more remarkable in the shrunken state in the poor solvent. The application of these phenomena to a molecular actuator has been proposed.
Ordered Structure in Alloy Grains of Iron-Nickel Produced by the Gas Evaporation Technique
Authors: Kaito Chihiro , Saito Yoshio , Fujita Kazuo
Published: February 2005

It has been shown that ultrafine grains of ordered structure of Fe3Ni, FeNi and FeNi3 can be produced by the gas evaporation technique. The ordered structure of the Fe3Ni can be explained as a structure of the Fe3Al type (DO3). The ordered structures of FeNi and FeNi3 were of the AuCuI (LI0) and Cu3Au (LI2) types, respectively. The difference of the morphology due to crystal structures has been shown.
High-Energy Electron Production by an Electromagnetic Wave with a Static Magnetic Field
Authors: Kawata Shigeo , Manabe Atsushi , Takeuchi Satoshi
Published: February 2005

A new mechanism is presented for high-energy electron production from an electron beam by an electromagnetic (EM) wave with a static magnetic (B) field. Numerical analyses and simulations show that this mechanism works well for high-energy-electron production. Typically the magnitude of the static B field is significantly small compared with the amplitude of the EM wave. The optimal magnitude of the static B field is also discussed.
Application of Perovskite-Type Oxides to the Sensing Electrode of a LaF3-Based Oxygen Sensor Workable at Room Temperature
Authors: Lukaszewicz Jerzy P. , Miura Norio , Yamazoe Noboru
Published: February 2005

LaF3-based oxygen sensors were constructed using six perovskite-type oxides for the sensing electrodes. It was found that oxygen sensing characteristics of the oxide electrodes, i.e., sensitivity to a change in oxygen partial pressure and response time, were greatly dependent on the oxide used, the dependence being closely related with the activity of the oxides for the electrochemical reduction of oxygen in solution. Among the oxides tested, LaCrO3, LaCoO3 and LaMnO3 were found to yield sensing electrodes with higher sensitivity and shorter response times than Pt sensing electrodes.
Isothermal Capacitance Transient Spectroscopy in ZnO Varistor
Authors: Maeda Takao , Meguro Sakae , Takata Masasuke
Published: February 2005

Isothermal capacitance transient spectroscopy was applied to the ZnO varistor. Spectroscopic signals obtained at around room temperature were related to the interface state of 0.60 eV below the conduction band edge. Furthermore, a bulk trap of 0.27 eV was detected at lower temperatures (121 K∼153 K), which corresponds to the result obtained by admittance spectroscopy.
Focusing of Intense Electron Beams with Novel High-Tc Superconducting Lenses
Authors: Matsuzawa Hidenori , Osada Tomoaki , Ishibashi Yoshiharu , Irikura Kazunori , Okamoto Kenji , Mochizuki Akihide , Wada Haruhisa , Akitsu Tetsuya
Published: February 2005

In this study, photographs were taken which definitely showed the focusing ability of superconducting lenses (Supertrons). High-T
c Bi- and Y-compound superconducting lenses with an inner diam of about 20 mm focused relativistic electron beams (REBs, 310 keV, 3.8 kA, with a duration time of less than 5 ns) to a diameter of 2.6 and 4.5 mm, respectively, at the exit of the lenses.
Effect of Rapid Solid-Phase Epitaxy of P+-Implanted Amorphous GaAs and GaAs/Si by Laser Beam Heating
Authors: Yoshino Kiyohiko , Murakami Kouichi , Masuda Kohzoh
Published: February 2005

Solid-phase epitaxy (SPE) of amorphous GaAs(a-GaAs) layers produced by P+ ion implantation was successfully performed by cw-Kr laser irradiation. High-power and short-duration (1.5 ms) laser heating results in rapid SPE at relatively high temperatures. By micro-Raman scattering measurements, perfect recovery of crystallinity is observed for the rapid SPE of a-GaAs layers of GaAs substrates. Furthermore, also for the a-GaAs layer of thin molecular beam epitaxy (MBE) GaAs on Si, the crystallinity of the layer is found to be improved by the rapid SPE, compared to the initial crystallinity of the thin MBE-GaAs on Si.
Optical Absorption Spectra of Band-Edge Modulated a-Si1-xNx:H Films
Authors: Ogihara Chisato , Ohta Hiroshi , Yamaguchi Masaaki , Morigaki Kazuo
Published: February 2005

We have prepared a-Si1-x
N
x
:H samples which have a sinusoidally modulated band-edge structure. The period, L, ranges between 30 Å and 300 Å. The optical absorption spectra have been measured and the optical gap has been obtained for the samples, The optical gap increases with decreasing L. This result can be explained in terms of an effective mass equation for electrons and holes in respective bands under the modulated potentials.
The Effect of Ca2PbO4 Addition on Superconductivity in a Bi-Sr-Cu-O System
Authors: Uzumaki Takuya , Yamanaka Kazunori , Kamehara Nobuo , Niwa Koichi
Published: February 2005

We examined the effect of Ca2PbO4 addition on superconductivity in a Bi-Sr-Cu-O system. We determined that Ca2PbO4 is formed in Bi-Pb-Sr-Ca-Cu-O at temperatures lower than 750°C on the basis of powder X-ray diffraction and micro-Raman scattering. A high-T
c phase was synthesized by adding Ca2PbO4 to the Bi-Sr-Cu-O system which has a single CuO layer. It seems that the synthesis process of the high-T
c phase is based on a reaction between the low-T
c structure and Ca2+ in the liquid phase which is caused by decomposition of Ca2PbO4 at 822°C.
Picosecond Characterization of InGaAs/InAlAs Resonant Tunneling Barrier Diode by Electro-Optic Sampling
Authors: Tackeuchi Atsushi , Inata Tsuguo , Muto Shunichi , Miyauchi Eizo
Published: February 2005

We have studied the dynamic response of the InGaAs/InAlAs resonant tunneling barrier (RTB) diode using electro-optic sampling. We have confirmed that the switching time decreases with the barrier thickness. We propose an equivalent circuit model of the RTB diode to phenomenologically treat the “state-lifetime”, that is, the quantum mechanical lifetime of the resonant-state formed in the quantum well. Using this model, we have found that the experimental state-lifetime is smaller than its calculated value in the unbiased condition.
Characteristics of Holes Investigated by ESR in High-Tcphase of Bi(Pb)-Sr-Ca-Cu-O System
Authors: Hayashi Yoshikazu , Fukui Minoru , Sasakura Hiroyuki , Minamigawa Shinnosuke , Fujita Tetsuo , Nakahigashi Kiyotaka
Published: February 2005

Measurements of nonresonant and ESR absorption are made in the high-Tcphase of the Bi(Pb)-Sr-Ca-Cu-O system. Two components of ESR signals have been detected above the superconducting transition temperatureTc. One is anisotropic and the other is isotropic. The isotropic spectrum is not considered to arise from impurities. The nonresonant microwave absorption near zero magnetic field is greatly enhanced atTcand the ESR signals are almost completely masked. The origin of the ESR is discussed in relation to doped holes.
Superconductivity Near 50 K in a Bi-La-Ca-Cu-O System
Authors: Inoue Osamu , Adachi Seiji , Takahashi Yukihiro , Hirano Hirofumi , Kawashima Syunichiro
Published: February 2005

A new oxide superconductor has been found in the Bi-La-Ca-Cu-O system. The maximum onset temperature and zero resistance temperature were 52 K and 21 K, respectively, obtained for a nominal composition of Bi2La0.5Ca3.5Cu3O
x
ceramics sintered at 830°C for 110 h in air. The powder X-ray diffraction patterns of this ceramic were well indexed by a tetragonal symmetry with a=0.54 nm and c=2.98 nm, which is similar to that of Bi2Sr2CaCu2O
x
ceramics.