巻号一覧
65 巻, 11 号
選択された号の論文の46件中1～46を表示しています
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Kazume Nishidate, Mamoru Baba, Richard J. Gaylord専門分野: Statistical physics and thermodynamics.
1996 年 65 巻 11 号 p. 3415-3418
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありA new stochastic discrete space-time model is proposed to simulate abiased diffusive system of two species in two dimensions. A very simple rule set which prohibits the multiple occupancy of a latticesites by particles while conserving their number, is used to definethe dynamics.We found that spatial inhomogeneous bands in high-density statespromptly form as the time step increases.The biased diffusive cell automaton (BDCA) model is analyzed and discussed.抄録全体を表示PDF形式でダウンロード (481K) -
Shoichi Kai, Yoshiki Hidaka, Ken–ichi Hayashi, Michael I. Tribel ...専門分野: Statistical physics and thermodynamics.
1996 年 65 巻 11 号 p. 3419-3422
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありThe process of annihilation of two point defects with opposite topological charges in a roll pattern is discussed for electrohydrodynamic convection in a nematic layer. It is shown that at the final stage of the process the distance between the centers of defects which are being annihilated varies as the square root of the time, down-counted from the annihilation moment. Such a scaling is associated with topological properties of the slowly varying complex amplitude of the order parameter and is suggested as a generic law for annihilation or spontaneous, barrierless nucleation of pairs of defects in extended systems. Experimental evidence of the scaling in the case of electrohydrodynamic convection in MBBA is obtained.抄録全体を表示PDF形式でダウンロード (401K) -
Syuji Miyazaki, Hirokazu Fujisaka専門分野: Statistical physics and thermodynamics.
1996 年 65 巻 11 号 p. 3423-3425
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありA four-dimensional Poincaré map is obtained from a coupling between a pair of nonlinear oscillators and it shows on-off intermittency under proper conditions. The power spectrum, and the distribution of on-off variable and that of laminar duration are numerically obtained and compared with analytical results of the multiplicative noise model, which is a reduced form of the large friction limit of the original Poincaré map. The coupled system considered here is a good candidate with which to observe on-off intermittency experimentally.抄録全体を表示PDF形式でダウンロード (229K) -
Hirokazu Fujisaka, Tomoji Yamada専門分野: Statistical physics and thermodynamics.
1996 年 65 巻 11 号 p. 3426-3429
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありA statistical theory on the transient process in a multiplicative noise system is developed. The system is set to be below the critical point where the dynamic variable approaches zero under the influence of the multiplicative noise. It is numerically shown that the first passage time distribution exhibits a single peak structure, and that it has an exponential form for long first passage times. We derive approximate analytic expressions for the first passage time distributions, which are in fairly good agreement with numerical results, where particularly concerning in relation to the nonlinear fluctuation effects.抄録全体を表示PDF形式でダウンロード (282K) -
Osamu Fukumasa, Hideki Nishimura専門分野: The physics of plasmas and electric discharges.
1996 年 65 巻 11 号 p. 3430-3433
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありThe production of hydrogen negative ions H- in a pure volume source has been studied. In our double plasma negative ion source, both energy and density of fast electrons are well controlled. Using this source, enhancement of H- production has been achieved. The extracted H- current in the double plasma operation is higher than that in the single plasma operation when observed under the same discharge power. Measurements of plasma parameters in the source and in the extractor regions have been carried out for both cases. Enhancement of H- production is achieved by optimizing plasma parameters for a so-called two-step process of H- volume production.抄録全体を表示PDF形式でダウンロード (325K) -
Shinichiro Kado, Hiroshi Nakatake, Katsunori Muraoka, Katsumi Kondo, F ...専門分野: The physics of plasmas and electric discharges.
1996 年 65 巻 11 号 p. 3434-3437
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありEnhancement and suppression of electron density fluctuations around the electron drift frequency was observed in Heliotron E. This behavior corresponded to changes in the density profiles. Density fluctuations around this frequency were enhanced when the density profile was peaked in the inner region, and suppression was associated with the flattening of the density profile. An examination of the frequency, wavenumber, and collisionality regimes suggested that the most likely candidate for the instability responsible for driving these fluctuations is the collisionless circulating electron mode.抄録全体を表示PDF形式でダウンロード (393K) -
Tomohiro Yamaguchi, Mitsuhiko Maesato, Seiichi Kagoshima専門分野: Electronic transport in condensed matter.
1996 年 65 巻 11 号 p. 3438-3441
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありWe investigated voltage-response waveforms to repetitive current pulsesand found pulse-duration memory effects in the spin-density wave (SDW) phaseof (TMTSF)2AsF6; i.e., voltage enhancement at the end of pulses androunding of the leading edge of voltage waveforms.These effects are observed under electric fields larger than ETthroughout the temperature range from 0.5 K to 4.2 K.SDW appear to “learn” the change of the pulse duration in the first pulseof the new duration.抄録全体を表示PDF形式でダウンロード (293K) -
Yoshitake Ueda, Kazuhiro Sakoh, Eiji Hashimoto専門分野: Electronic transport in condensed matter.
1996 年 65 巻 11 号 p. 3442-3444
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありNegative resistance has been observed at 4.2K in a cross-shaped specimen cut from a high-purity aluminum single crystal with a residual resistance ratio of about 100000. The cross section of arms of the specimen was 0.5mm × 0.4mm and the bulk mean free path lb of conduction electrons was about 3, mm. The negative resistance was enhanced in a magnetic field parallel to a pair of arms. Nonlinear I-V characteristics were also observed when one of the potential probes was placed on the middle part of an arm at a distance 2, mm (< lb) from the center of the intersection of the arms. The negative resistance and the nonlinear I-V characteristics were attributed to the ballistic conduction of electrons.抄録全体を表示PDF形式でダウンロード (252K) -
Yoshimasa Isawa専門分野: Electronic transport in condensed matter.
1996 年 65 巻 11 号 p. 3445-3448
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありA new approach to derive the Landauer formula is developed by treating the current flowing ballistic conducting channel as an open system, in which an electronic distribution function shifts in proportion to an external current flow. The effect of an open system is taken into account by means of the Lagrange multiplier. By introducing current reflection and transmission coefficients, and by explicitly treating the voltage drop under the condition that the contact between the lead and the electrode is ideal, two types of circuit equations corresponding to two Landauer formulas are obtained. In our analysis, the Landauer formula is not reproduced when there are no scattering centers in each lead, i.e., each lead is ideal, but is reproduced when there is no elastic scattering and the phase coherence is lost in each lead.抄録全体を表示PDF形式でダウンロード (325K) -
Keiji Ono, Hiroshi Shimada, Shun–ichi Kobayashi, Youiti Ootuka専門分野: Electronic structure and electrical properties of surfaces, interfaces and thin films.
1996 年 65 巻 11 号 p. 3449-3451
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありWe report experimental results on the arrays of small $<0.01 μm2) Ni/NiO/Co tunnel junctions. At high temperatures or high bias conditions, we observed magnetoresistance due to changes in the relative orientation of magnetization of the electrodes. In the Coulomb blockade regime, magnetoresistance is bias-dependent and a large negative magnetoresistance of up to 40% was observed.抄録全体を表示PDF形式でダウンロード (253K) -
Manfred Sigrist, Michael E. Zhitomirsky専門分野: Superconductivity.
1996 年 65 巻 11 号 p. 3452-3455
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありThe list of possible superconducting states withodd parity for Sr_2 RuO_4 contains nonunitary phases.These phases have gapless quasi-particle excitations which could explainthe large residual density of states observed experimentally in thesuperconducting phase. An energy analysis is performed, which shows that a specialmechanism is needed in addition to weak coupling in order to stabilize thenonunitary phase. Various experiments which may provideadditional information on the unusual properties of thesuperconducting phase are discussed.抄録全体を表示PDF形式でダウンロード (397K) -
Kazushige Machida, Tetsuo Ohmi専門分野: Superconductivity.
1996 年 65 巻 11 号 p. 3456-3459
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありIn response to the recent remarkableKnight shift and the neutron scattering experiments on UPt_3, a pairing mechanism is proposed on the basis of spin fluctuation theory.The proposed mechanism gives a new interpretation of the double transitions, lending further support to our previous spin space degenerate scenario where the order parameter ischaracterized by a nonunitary triplet pairing belonging to one-dimensional representation in weak spin-orbit coupling. It is found thata novel heavy Fermi liquid state with a bandwidth of -- 10 K almost isotropic in spin space must exist near the Fermi surface.Several decisive experiments are pointed out to check our proposals.抄録全体を表示PDF形式でダウンロード (443K) -
Hideto Imai, Hirofumi Wada, Masayuki Shiga専門分野: Magnetic properties and materials.
1996 年 65 巻 11 号 p. 3460-3463
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありThe specific heat of BaVS3, which undergoes a metal-insulator transition at TMI=70 K, was measured in the temperature range of 1.4 K to 300 K. A specific heat anomaly was found at TMI.The entropy change associated with this anomaly is estimated to be 4.7 J/K mol, which is close to R ln 2, the expected magnetic entropy for S=1/2 spins of V atoms. At low temperatures, a T-linear contribution of the specific heat with an apparent γ value of 15.7 mJ/K2 mol was observed in spiteof the absence of conduction electrons. This T-linear contribution may be attributed to spin wave excitations for a one-dimensional antiferromagnet.抄録全体を表示PDF形式でダウンロード (358K) -
Hiroshi Yamamoto, Isamu Oguro, Masayasu Ishikawa専門分野: Magnetic properties and materials.
1996 年 65 巻 11 号 p. 3464-3466
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありWe report the magnetic properties of Ce2CuGe6 and Pr2CuGe6, both of which exhibit a ferrimagnetic order around 15, K. Hysteretic curves with small residual magnetization, 7.8× 10-4, μ B/f.u. and 1.1× 10-2, μ B/f.u., are observed for Ce2CuGe6 and Pr2CuGe6, respectively. The peak of specific heat and the sharp decrease of electrical resistivity near their ordering temperature are consistent with observed magnetic orders.抄録全体を表示PDF形式でダウンロード (224K) -
Takashi Tayama, Kenichi Tenya, Hiroshi Amitsuka, Toshiro Sakakibara, A ...専門分野: Magnetic properties and materials.
1996 年 65 巻 11 号 p. 3467-3470
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありThe ac susceptibility χac and the dc magnetization M(H, T) of single crystals of Sm_3Te_4 have been measured at temperatures as low as 70 mK.A cusp is found in χac at 1.3 K which is slightly lower than the temperature at which a broad peak of the specific heat was previously observed. Distinct irreversibility is observed in M(H, T) below --1.3 K. The results indicate that the Sm3+ moment undergoes a spin glass transition at Tg--1.3 K. It is likely that the two valence states of Sm2+(J=0) and Sm3+(J=5/2) are randomly frozen at low temperatures in the bcc lattice to effectively form a randomly diluted antiferromagnet.抄録全体を表示PDF形式でダウンロード (351K) -
Hirofumi Wada, Akihiro Mitsuda, Masayuki Shiga, Hiroko Aruga Katori, T ...専門分野: Magnetic properties and materials.
1996 年 65 巻 11 号 p. 3471-3473
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありIn order to study the magnetic field effects on the intermediate valence of the Eu system, magnetization was measured for EuPd2Si2 and Eu(Pd0.95Pt0.05)2Si2 up to 100 T. A first-order metamagnetic transition was observed for both samples under high magnetic fields. The transition field is 93T for EuPd2Si2 at 6 K. The saturation magnetization close to 7x{μx}B indicates that this metamagnetism is a field-induced valence transition from an intermediate valence state to a divalent state of the Eu ion. Based on the interconfigurational fluctuation (ICF) model, the excitation energy to convert an Eu3+ ion into Eu2+ was estimated. Temperature dependence of the metamagnetic transition field of EuPd2Si2 was also studied.抄録全体を表示PDF形式でダウンロード (265K) -
Sigenori Tsuji, Ken–ichi Kumagai, Masatsune Kato, Yoji Koike専門分野: Magnetics resonances and relaxations in condensed matter; MÖssbauer effect.
1996 年 65 巻 11 号 p. 3474-3477
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありWe have investigated spin dynamics of both the ladder and the chain sites in Sr14Cu24O41 by Cu-NMR and Cu-NQR. From the NMR shift, Kspin, and nuclear spin-lattice relaxation time, T1, the energy gaps in the spin excitation spectrum are confirmed to be {Δ}=140, K for the chain site and {Δ}=470, K for the ladder site for Sr14Cu24O41. Doping effects on the spin gaps and electric field gradient at the Cu sites were also investigated by the substituting of Ca, Y and La for Sr. The spin gap of the ladder site decreases with increasing x for Sr14-xCa_xCu24O41 and seems to collapse at around x=13 for Ca substitution.抄録全体を表示PDF形式でダウンロード (380K) -
Osamu Moriyama, Mitsugu Matsushita専門分野: Other areas of research of general interest to physicists.
1996 年 65 巻 11 号 p. 3478-3481
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありWe investigate the structure and statistics of clusters constructed using the coupled tent map. Some quantities, such as the cluster-size distribution, the density of turbulent sites and the standard deviation of the cluster height, show power-law behaviors at the critical state. We found that although these exponents vary according to the parameter r characterizing the tent map, one scaling relation is always satisfied.抄録全体を表示PDF形式でダウンロード (325K) -
Ning Wang専門分野: Mathematical methods in physics.
1996 年 65 巻 11 号 p. 3483-3491
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありAn inverse scattering problem for a layered medium that supports N types of linear waves is considered, that is an 2N× 2N generalization of the Dirac type equation in one dimension. Both the direct and inverse scattering problems for this problem are studied. The relevant inverse problem is formulated to a uniquely solvable Riemann-Hilbert problem which can be transformed to a matrix singular integral equation. It is shown that the only contribution to reconstruction of potentials vanishing at infinity, comes from the solution which is normalized to identity matrix I at infinity. The remarkable difference from the conventional “regular” N× N first order linear spectral problem is that the problem considered here are of both the properties of the well-known 2× 2 Dirac type equation and the properties of the conventional “regular” N× N first order linear spectral problem.抄録全体を表示PDF形式でダウンロード (655K) -
Kae Nemoto, Fumiaki Shibata専門分野: Statistical physics and thermodynamics.
1996 年 65 巻 11 号 p. 3492-3499
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありA projection operator method in Heisenberg picture is developed. Corresponding to the equations for the reduced density matrix, there are two types of Langevin-like equations; time convolution (TC) and time convolutionless (TCL) equations.When the whole system is composed of relevant system and irrelevant system, unnecessary information is eliminated by projection operator. Explicit expansion formulae are obtained for the both types of equations. Relaxation operators and fluctuating forces are expressed in terms of certain cumulants.The method is illustrated by simple examples.抄録全体を表示PDF形式でダウンロード (410K) -
Takahiro Yamaguchi, Hirokazu Ohtagaki専門分野: Statistical physics and thermodynamics.
1996 年 65 巻 11 号 p. 3500-3512
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありWe have studied the order of appearance ofoscillation modes associated with a piecewise linear map (PLM)obtained from the Oregonator model excited by an external periodic force(Acos(ω τ)).It is shown that the bifurcation of the transition from m-peak oscillation ( m-PO) to (m+1)-PO occurs when the value of a shift parameter in the PLM varies from large to small. The region of appearance of the oscillation mode π r, s(m, m+1) consisting of r times of m-PO and s times of (m+1)-PO is obtained from analytical treatment, where r, s and m are the positive integers, respectively. The series of the winding number of the oscillation mode π r, s(m, m+1) form a part of successive Farey series, and the Farey series can be decomposed into the part of series of unstable oscillation mode and that of stable oscillation mode. The bifurcation diagram of the order of appearance of the oscillation mode π r, s(m, m+1) in the PLM has a self similar hierarchy. Analyzing theoretically the order of appearance of the oscillation mode π r, s(m, m+1) and m-PO in the PLM, we can explain the order of appearance of the oscillation modes in the parameter space (A, ω) for the Oregonator excited by Acos(ω τ).抄録全体を表示PDF形式でダウンロード (748K) -
Hiroki Saito, Hiroyuki Hyuga専門分野: Optics.
1996 年 65 巻 11 号 p. 3513-3523
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありDynamical Casimir effects caused by a moving mirror and a varying dielectric medium are studiedin the effective Hamiltonian approach.The explicit form of the effective Hamiltonian for the uniform, step-wise, and time-dependent dielectric model is derived in addition tothat for the moving mirror model.The resonant properties of induced photons for both models areconsidered and it is found that in contrast to the moving mirror case, the inter-mode transition for the dielectric case is suppressed betweenthe odd-odd levels and between the even-even levels.The effects of dissipation are also taken into account by the masterequation.For numerical analyses, a convenient method to integrate the timeevolution is proposed.抄録全体を表示PDF形式でダウンロード (811K) -
A. M. El Misery, Elsayed F. Elshehawey, A. A. Hakeem専門分野: Mechanics, elasticity, and rheology.
1996 年 65 巻 11 号 p. 3524-3529
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありPeristaltic flow in a two-dimensional channel with a sinusoidal wave is analyzed. Under the assumption of creeping motion, the problem is formulated using a perturbation expansion in terms of a variant of the Weissenberg number. To determine the characteristics of the peristaltic motion of shear thinning non-Newtonian fluids, the motion of a Carreau fluid in a planar channel having walls that are transversely displaced by an infinite, harmonic traveling wave of large wavelength and neglecting wave number. We found the pumping rate of a Carreau fluid is less than that for a Newtonian having a shear viscosity the same as zero-shear-rate viscosity of the non-Newtonian fluid. The peristaltic pumping and the augmented pumping are discussed for various values of the physical parameters of interest.抄録全体を表示PDF形式でダウンロード (383K) -
Masayoshi Taguchi専門分野: Kinetic and transport theory of fluids; physical properties of gases.
1996 年 65 巻 11 号 p. 3530-3536
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありThe neoclassical bootstrap current for an anisotropic plasma has been studied in a large aspect-ratio tokamak. The enhancement factor due to the temperature anisotropy in the equilibrium electron distribution function is explicitly calculated, and is shown to reach to about 1.5 when the perpendicular temperature is twice as large as the parallel temperature.This bootstrap current is also predicted to have the component proportional to the radial electric field even in an axisymmetric magnetic field.抄録全体を表示PDF形式でダウンロード (445K) -
Chikako Moriyoshi, Kazuyuki Itoh専門分野: Structure of liquids and solids; crystallography.
1996 年 65 巻 11 号 p. 3537-3543
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありAccurate crystal structure of K_2Zn_2(SO_4)_3 was determined at seven temperatures in the high-temperature cubic phase. It turned out that the SO_4 ion has multi-site molecular arrangements. We also found that mean-square atomic displacements and extinction parameters of diffraction intensities become anomalously large with approaching the phase transition temperature. These peculiar features, which are also observed for other langbeinite-type crystals, are explained by assuming that nuclei of a low-temperature phase have already been generated in the high-temperature cubic phase. We discuss that the nuclei are produced by the short Zn--O distances.抄録全体を表示PDF形式でダウンロード (571K) -
Kazuyuki Itoh, Noriaki Nakamura専門分野: Structure of liquids and solids; crystallography.
1996 年 65 巻 11 号 p. 3544-3550
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありThe validity of a split-atom method (SAM), which is a technique to determine the disordered structure, is examined by a computer simulation based on a simple structure model. It turns out that the distance between equilibrium positions and the thermal vibrationsof the disordered atom exert a significant influence on revealing the structural disordering. However, it is concluded that a resolving power of SAM is governed by the accuracy of the diffraction intensity measurement. We propose an experimental method to determine the disordered structure with adjacent equilibrium positions.抄録全体を表示PDF形式でダウンロード (516K) -
Tomonori Koda, Manabu Numajiri, Susumu Ikeda専門分野: Structure of liquids and solids; crystallography.
1996 年 65 巻 11 号 p. 3551-3556
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありA binary system of parallel hard spherocylinders and hard spheres areconsidered to examine influence of addition of spherical molecules tothe pure system of rod-like molecules, especially the influence on the structure of the smectic-A phase.Free energy of the system is calculated through the second virial approximation, and nematic--smectic-A transition isestimated by stability analysis of nematic state with sinusoidal densityfluctuation.Constant pressure Monte Carlo simulation is also used to confirm a prediction of the stability analysis which prediction indicates that the addition of spherical molecules induces a smectic-A phase as a microphase separationbetween the spheres and the spherocylinders.抄録全体を表示PDF形式でダウンロード (389K) -
A. K. M. A. Islam, M. T. Hoque専門分野: Mechanical and acoustical properties of condesed matter.
1996 年 65 巻 11 号 p. 3557-3562
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありAn analysis of thermal expansion of Li(H, D) systems up to melting temperature has been performed using the theory of anharmonic lattice. The high temperature contribution to expansivity due to thermal defects is evaluated. An extension of the study to Na(H, D) systems limiting the upper temperature to 350K even where very little or no data are available led us to predict the hitherto unknown lattice constants at 0K for the crystals. The temperature dependence of the elastic constants for Li(H, D) systems up to 920K (350K for Na(H, D)) has also been evaluated and compared with other available calculations.抄録全体を表示PDF形式でダウンロード (534K) -
Kazuo Sasaki, Shigenori Usui専門分野: Equations of state, phase equilibria, and phase transitions.
1996 年 65 巻 11 号 p. 3563-3570
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありThe finite-temperature phase diagramis studied for an axial chiral XY model with p, -fold anisotropyin which the nearest neighbor spins along a particular direction are coupled through the chiral interaction whilethose in a plane perpendicular tothis direction are coupled ferromagnetically;the ground-state of the model is known to have a complicated phasediagram characterized by the devil's staircase.By using the mean-field theory, the cases of p = 2, 3, 4 and 6 are investigated.The global phase diagram is constructed by employing theminimization eigenvalue method to find the spin configurationthat minimizes the free energy.Certain properties of the phase diagram are studied analytically.The structure of the finite-temperature phase diagram is found tochange qualitatively with p, though the qualitative feature of the ground-state phase diagramis known to be independent of p ≥ 2.抄録全体を表示PDF形式でダウンロード (702K) -
Nguyen Van Hung, Ronald Frahm, Hiromichi Kamitsubo専門分野: Thermal properties of condensed matter.
1996 年 65 巻 11 号 p. 3571-3575
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありIn this work the anharmonic contributions to the high-temperature EXAFS spectra have been evaluated by considering the anharmonic contributions to the thermal vibrations of atoms and using the single-shell model. The anharmonicity calculated by our new formula is proportional to the temperature and inversely proportional to the distance between the absorbing atom and its neighbour located in a spherical shell which can be considered as the outer shell in the case of particles. The measured EXAFS spectra of Cu at several temperatures have been presented providing its strucuctural informations, among them the atom position of the first shell is different from the one calculated by the harmonic model by 0.05Å at 700K and 0.01Å at 295K. These measured results agree very well with the ones calculated by present anharimonic theory. This creates a good possibility for extraction of physical parameters from experiment by using our procedure.抄録全体を表示PDF形式でダウンロード (401K) -
Yukio Saito, Makio Uwaha専門分野: Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties).
1996 年 65 巻 11 号 p. 3576-3581
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありA step growing in a diffusion field is unstable due to the Schwoebeleffect when it advances too fast.A continuum model equation is derived for morphological evolution of the unstable step by taking account of the anisotropy effect in the stiffness.The anisotropy brings up an additional term (∂ H/∂ X)^2 ∂ ^2 H/∂ X^2in the Kuramoto-Sivashinsky equation that describes an isotropic step.Unless direction of the growth corresponds to the one with the stiffness minimum, the morphology is chaotic in space and time.When the step advances in the direction of the stiffness minimum and the anisotropy is sufficiently strong, the step takes a periodic structure.抄録全体を表示PDF形式でダウンロード (454K) -
Katsuyuki Matsunaga, Isao Tanaka, Hirohiko Adachi専門分野: Electron states in condensed matter.
1996 年 65 巻 11 号 p. 3582-3590
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありWe have performed the electronic structure calculation of an interstitial cationic defect in AgCl and NaCl crystals, using the DV-Xα molecular orbital method. Ag-4d orbitals are well admixed with Cl-3p orbitals in the valence band, and the electronic structure of AgCl is quite different from that of NaCl. The cation-anion covalent bonding in AgCl is stronger than that in NaCl. In addition, it is found that an interstitial Ag has a considerably strong covalent bonding with its surrounding Ag because of the interaction between Ag-4d orbitals. Such a covalent bonding between Ag ions is likely to play an important role for the stabilization of an interstitial Ag in AgCl.抄録全体を表示PDF形式でダウンロード (764K) -
Shin–ichi Kimura, Mikihiko Ikezawa, Akira Ochiai, Takashi Suzuki専門分野: Electron states in condensed matter.
1996 年 65 巻 11 号 p. 3591-3598
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありTemperature dependence of the electronic structure of Yb4As3 was investigated by the observation of the reflectivity spectra in the energy range from 2meV to 50eV at several temperatures from 39 to 320K. In the photon energy range below 10meV, the temperature dependence of the spectrum can be qualitatively explained by two-band model previously proposed. An absorption band with strong temperature dependence was observed at 0.4eV. The origin is considered to be the mixing state between unoccupied Yb3+-4f and 5d. The state is considered to be important to understand the anomalous temperature dependence of the physical properties. In the energy range above 1eV, the spectrum does not change with the temperature. The structure of the occupied and unoccupied states near the Fermi level is clarified.抄録全体を表示PDF形式でダウンロード (730K) -
Yoshinori Kobayashi, Takashi Nakayama, Hiroshi Kamimura専門分野: Electron states in condensed matter.
1996 年 65 巻 11 号 p. 3599-3603
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありThe electronic structure and optical transition strengths of the (GaP)m_1(AlP)n_1(GaP)m_2 (AlP)n_2 … type multi-quantum-well superlattices (MQS's) are calculated with use of the ab initio pseudopotential method within the local density approximation. It is shown that the thickest layers of GaP and AlP are a dominant factor of determining band-gap energy of MQS, while other thin “spacer” layers critically change the transition strengths. Especially, the strong transition strength is obtained when the spacer consists of thinner GaP and AlP layers. Excitonic effect on the photoluminescence is briefly discussed.抄録全体を表示PDF形式でダウンロード (444K) -
Michiyasu Mori, Hidetoshi Fukuyama専門分野: Electron states in condensed matter.
1996 年 65 巻 11 号 p. 3604-3614
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありThe doped Mott insulator in one dimension has been studied based on the phase Hamiltonian with the Umklapp scattering process, in which the charge degree of freedom is described by the quantum sine-Gordon model. The well-known equivalence between the quantum sine-Gordon model and the massive Thirring model for the spinless fermion makes it clear that the Mott-Hubbard gap originates from the Umklapp scattering process as was indicated by Emery and Giamarchi. Compressibility, density-density correlation function, frequency dependence of optical conductivity and Drude weight have been calculated in the presence of the impurity scattering treated in the self-consistent Born approximation. It is seen that there exists a crossover behavior in the spectral weight of charge excitations: the acoustic mode is dominant in small wave number region while the optical excitations across the Mott-Hubbard gap lie in large wave number region and that this crossover wave number is reduced as the Mott transition is approached.抄録全体を表示PDF形式でダウンロード (878K) -
Hisatoshi Yokoyama, Masao Ogata専門分野: Electron states in condensed matter.
1996 年 65 巻 11 号 p. 3615-3629
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありTwo-dimensional t-J model is studied by a variationalMonte Carlo method, using Gutzwiller-Jastrow-typewave functions.Various kinds of superconducting pairing symmetries arecompared in order to determine the phase diagram of the ground state in thefull J/t-n plane.Near the half filling where thehigh temperature superconductivity is expected, the dx2-y2-wave pairing state is always the most stable among varioussymmetries.The three-site term hardly changes the phase diagram in this regime.In the low electron density, the extended s-type wave becomes a quantitativelygood state for large J/talthough the energy gain is small.The Gutzwiller wave function is shown to be the exactground state in the low-electron-density limit for the supersymmetriccase (J/t=2).抄録全体を表示PDF形式でダウンロード (1322K) -
Yositake Takane, Yasusi Koyama専門分野: Electronic transport in condensed matter.
1996 年 65 巻 11 号 p. 3630-3637
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありA one-dimensional interacting electron gas (N) in contact with a bulk superconductor (S) is studied theoretically using a bosonization method. We calculate various correlation functions in the case of the complete Andreev reflection at zero temperature. It is found that a tendency towards singlet superconductivity is enhanced in the vicinity of the NS interface, while spin-density-wave correlation is shown to be suppressed. We calculate the conductance of the NS interface in the presence of a barrier potential. This interface conductance shows relatively strong temperature dependence compared with conductance through a single barrier in the absence of the proximity effect. This is a manifestation of interplay between the proximity effect and the mutual interaction.抄録全体を表示PDF形式でダウンロード (613K) -
Atsutaka Maeda, Tetsuo Hanaguri, Yoichi Iino, Sohichiroh Masuoka, Yasu ...専門分野: Superconductivity.
1996 年 65 巻 11 号 p. 3638-3645
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありThe in-plane London penetration depth λab was investigated as a function of magnetic field H in YBa2Cu3Oy, Bi2Sr2CaCu2Oy and Tl2Ba2CaCu2Oy. λab changes linearly with H at low temperatures, with an almost temperature independent gradient.Below a crossover field H', the H-linear λ changes into an H2 behavior.The crossover from H to H2, the magnitude and temperature dependence of H', and the temperature dependence of the gradient of the H2 term around zero field are all consistent withthe nonlinear Meissner effect in unconventional superconductors.The results of these studies suggest that the order parameter of the double layered cuprates has nodes in k space.抄録全体を表示PDF形式でダウンロード (718K) -
Yoshinori Haga, Etsuji Yamamoto, Yoshihiko Inada, Dai Aoki, Kenichi Te ...専門分野: Superconductivity.
1996 年 65 巻 11 号 p. 3646-3653
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありNormal and superconducting properties of single crystalline UPd2Al3 have been studied by static magnetization, AC susceptibility and magnetoresistance measurements. In the normal state, an open orbit is found to exist along the [0001] direction from a saturated magnetoresistance. In the superconducting state, a pronounced peak effect is observed just below the upper critical field Hc2. The peak consists of two structures at low temperatures, becomes one above 0.6 K and continues up to a low field of 0.1 T. These experimental results are compared to those based on the FFLO model. The paramagnetic effect in superconductivity is also found by the static magnetization measurement.抄録全体を表示PDF形式でダウンロード (575K) -
Kenichi Katoh, Mitsuo Kasaya専門分野: Magnetic properties and materials.
1996 年 65 巻 11 号 p. 3654-3660
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありLattice parameter, electrical resistivity ρ, Hall constant RH and magnetic susceptibility χ have been measured for Ce3Au3-xPtxSb4 (x=0.0, 0.5, 1.0, 1.5, 2.25, 3.0). It is found that the alloys for all x show semiconducting behavior. The magnetic susceptibilities for all x obey the Curie-Weiss law at high temperatures and the effective magnetic moments are close to the value for the free Ce3+ ion. The paramagnetic Curie temperature increases with increasing x. From the results of the analysis based on a model of a mixture of Ce3+ and Ce4+ ions in Ce3Au3-xPtxSb4, it is revealed that the concentration of Ce4+ at low temperatures increase continuously with x and the paramagnetic Curie temperature is directly related to the activation energy between Ce4+ (J=0) and Ce3+ (J=5/2).抄録全体を表示PDF形式でダウンロード (600K) -
Teruhiko Akazawa, Takashi Suzuki, Fumihiko Nakamura, Toshizo Fujita, T ...専門分野: Magnetic properties and materials.
1996 年 65 巻 11 号 p. 3661-3665
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありIn concurrence with an antiferromagnetic transition at TN≅ 43K, UNiSn undergoes a semiconductor-to-metal phase transition. The powder X-ray diffraction reveals that the complex transition is accompanied also by a structural transition from a cubic to tetragonal symmetry. The temperature dependence of lattice parameters and that of Mössbauer spectra suggest that the transition is of first order and is a cooperative phenomenon of the structural and magnetic instabilities. However, an elastic modulus behaves as if the transition were of second order. This puzzle is solved by a scenario based on the crystalline-electric-field for 5f2 configuration in U4+ with the ground state of a non-magnetic doublet Γ3 in the cubic phase.抄録全体を表示PDF形式でダウンロード (433K) -
Takayuki Goto, Satoru Nakajima, Masae Kikuchi, Yasuhiko Syono, Tetsuo ...専門分野: Magnetics resonances and relaxations in condensed matter; MÖssbauer effect.
1996 年 65 巻 11 号 p. 3666-3671
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証あり63/65Cu/203/205Tl-NMR study has been performed on the Zn-substituted high-TC cuprate TlBa2Ca(Cu1-zZn_z)2O7+δ belonging to the over-doped region. The reduction rate in TC with Zn-concentration was much smaller than the lightly-doped cuprate La1.85Sr0.15CuO4, and showed a significant decrease with increasing hole concentration. The temperature dependence of the Cu-Knight shift in the superconducting state was successfully explained in terms of the partially closed d-wave model proposed by Ishida et al. The relation between the residual density of states in the superconducting state and the reduction rate of TC with Zn-concentration for slightly over-doped samples was well explained with Miyake's theoretical calculation on the potential scattering of the unitarity limit in the d-wave superconductor.抄録全体を表示PDF形式でダウンロード (520K) -
Katsumi Tanimura専門分野: Optical properties and condensedmatter spectroscopy and other interactions of matter with particles and radiation.
1996 年 65 巻 11 号 p. 3672-3675
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありThe yields of σ and π luminescence due to self-trapped excitons have been measured upon the three-photon excitation (TPE) which gives rise to the resonance on the upper branch of the lowest exciton-polariton in NaCl and KI. Both the σ and π luminescence are induced by the TPE in the whole wavelength range of the resonance, and the yield of the σ luminescence relative to that of the π luminescence is as high as that by the conventional band-to-band excitation, showing strong contrast to the result of the one-photon excitation (OPE) spectroscopy. The different feature of the σ -luminescence excitation in TPE from that in OPE has been discussed.抄録全体を表示PDF形式でダウンロード (396K) -
Makoto Tomita, Takeshi Onimaru専門分野: Optics.
1996 年 65 巻 11 号 p. 3676-3677
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありPDF形式でダウンロード (178K) -
Hitoshi Makino, Michisuke Kobayashi, Tomozo Tomoyose専門分野: Lattice dynamics and crystal statistics.
1996 年 65 巻 11 号 p. 3678-3679
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありPDF形式でダウンロード (168K) -
Hideki Watanabe, Eiichi Hirota, Iwao Ishida, Kouichi Hamada, Akira Oka ...専門分野: Magnetics resonances and relaxations in condensed matter; MÖssbauer effect.
1996 年 65 巻 11 号 p. 3680-3681
発行日: 1996/11/01
公開日: 1999/10/01
ジャーナル 認証ありPDF形式でダウンロード (189K)
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