Journal of the Physical Society of Japan
Online ISSN : 1347-4073
Print ISSN : 0031-9015
ISSN-L : 0031-9015
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Volume 58, Issue 11
Displaying 1-49 of 49 articles from this issue
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  • Relaxation of the Spin Autocorrelation Function in the Kinetic Ising Model with Bond Dilution
    Hiroshi Takano, Seiji Miyashita
    1989 Volume 58 Issue 11 Pages 3871-3874
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3871
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    The relaxation of the equilibrium correlation function q(t)=N−1 Σi=1N⟨Si(t)Si(0)⟩ is studied by the Monte Carlo method for the bond-diluted kinetic Ising model on the square lattice with a bond concentration below the percolation threshold. Here, the system has N Ising spins and Si denotes the i-th Ising spin. The correlation function q(t) seems to exhibit a nonexponential decay below the critical temperature of the nonrandom Ising model. An effective size ν of a cluster of ferromagnetically connected spins is defined as ν=(ln τ)2, where τ is the longest relaxation time in the cluster. It is found that the distribution function of ν behaves as P(ν)∝exp [−γν]. Although the asymptotic belaavior q(t)∼exp [−C(ln t)2] is not reached in the time region studied by the Monte Carlo method, this distribution explains the long-time behavior of q(t).
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  • Fractal Growth of Bacillus subtilis on Agar Plates
    Hiroshi Fujikawa, Mitsugu Matsushita
    1989 Volume 58 Issue 11 Pages 3875-3878
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3875
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    Bacteria have been shown to grow with various morphologies under different conditions on agar plates. A Bacillus subtilis strain was inoculated on the plate surface and incubated at 35°C. Colonies grew two-dimensionally with random branches, similar to clusters of the diffusion-limited aggregation (DLA) model. The colony patterns were analyzed and found to be self-similar with a fractal dimension of 1.716±0.008, in excellent agreement with the expected value of the DLA model. Interior branches were observed to stop growing in spite of their open neighborhood during the incubation period, implying the existence of a screening effect. These results clearly suggest that the colony pattern of the organism was formed through the DLA process. Moreover, the colonies were found to grow radially with almost regular branches on agar plates with moist surfaces, reminiscent of “dense radial” morphology.
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  • Flow at the Onset of Traveling Wave Convection
    Tohru Katoh, Yasuji Sawada
    1989 Volume 58 Issue 11 Pages 3879-3882
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3879
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    We studied steady and transient mass flow in a localized traveling wave state of convection of binary fluid mixture in an annular cell by use of a photochromic dye. The results indicate that no mass flow occurs across the self-organized boundary in a steady state, but that a large-scale flow exists at the transient stage to establish a localized traveling state. The transient flow was found to occur in the direction to lower the local critical Rayleigh number and to stabilize the localized convection state.
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  • An Origin of the Attractive Hubbard Model for High-Tc Superconductivity
    Hisashi Nishimura
    1989 Volume 58 Issue 11 Pages 3883-3885
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3883
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    A cause of the attractive Hubbard interaction is proposed which is based on a mechanism mediated by carrier plasmons, viz., density fluctuations of externally injected carriers (electrons or holes). This attractive interaction is dependent on the concentrations of low-density carriers and is dominant against the original repulsive Hubbard interaction in some favorable cases such as in low-density carriers occupying a band edge in two-dimensional (2-D) and/or three-dimensional (3-D) systems. The interaction derived is able to play a decisive role in understanding the mechanism of high-Tc superconductivity.
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  • Numerical Calculation for Quantum States of a Doped Fermion Coupled with Spins on a Frustrated Heisenberg Chain
    Masaaki Nojima, Atsushi Ohta, Toshihiko Suzuki, Yuhei Natsume
    1989 Volume 58 Issue 11 Pages 3886-3889
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3886
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    The behavior of a quantum island formed by a doped fermion to the oxygen site on a CuO2 plane in high-Tc superconducting oxides is investigated by the numerical calculation of the exact diagonalization for the Heisenberg s=1⁄2 chain system of 2×8, with special attention to the effect of the frustration introduced by the second nearest-neighbor antiferromagnetic exchange interaction. Though the island shrinks with increased coupling between the fermion and spins, it spreads significantly due to the essential contribution of the frustration.
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  • Pressure Effect on the Antiferromagnetism in La2CuO4−y
    Susumu Katano, Nobuo Môri, Hiroki Takahashi, Humihiko Takei
    1989 Volume 58 Issue 11 Pages 3890-3893
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3890
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    The antiferromagnetism in La2CuO4−y has been studied by neutron diffraction under hydrostatic pressures up to 1.5 GPa. The three-dimensional (3D) ordering temperature TN strongly increases with pressure at the rate of 18.5 K/GPa; thus, (1⁄TN)(dTN⁄dP) is 0.083/GPa. On the other hand, the ordered magnetic moment M is suppressed under pressure with (1⁄M)(dM⁄dP)∼−0.08⁄GPa. A correlation between the magnetism and superconductivity is discussed.
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  • Order Parameter in Quantum Antiferromagnets
    T. A. Kaplan, P. Horsch, W. von der Linden
    1989 Volume 58 Issue 11 Pages 3894-3898
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3894
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    We discuss the nature of symmetry breaking in quantum antiferromagnets. We show that published arguments concerning the order parameter for the 2d s=1⁄2 Heisenberg antiferromagnet have to be reconsidered. These had led to \sqrt3 and 1 for the ratio r of the mean z-component m of the staggered spin per particle msz in an infinitesimal staggered field B, to the r.m.s. value m0 of msz with B=0, in the thermodynamic limit. We give arguments which put doubt on both values. Also we prove r≥1, given m0≠0.
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  • Exact Anharmonic-Localized-Mode Solutions to the d-Dimentional Discrete Nonlinear Klein-Gordon Equation
    Shozo Takeno
    1989 Volume 58 Issue 11 Pages 3899-3909
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3899
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    Exact anharmonic-localized-mode solutions to the discrete nonlinear Klein-Gordon (NKG) equation defined in a d-dimensional version of the simple cubic lattice are obtained by using the lattice Green’s function method. For d≥3 there exists a critical value of the lattice anharmonicity for the appearance of the localized modes. An exact expression for the dispersion relation of a moving localized mode constituting a frequency band is obtained in terms of its shape functions. A comparison is made on the properties of moving and stationary or non-moving localized modes of the NKG equation with those of the d-dimensional discrete nonlinear Schrödinger equation. For d=1 one-localized-mode solution reduces in the continuum limit to the conventional one-soliton solution of the NKG equation.
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  • New Approach to Study Critical Dynamics by Using Continued Fraction Representation
    Chahn Lee
    1989 Volume 58 Issue 11 Pages 3910-3920
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3910
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    General feature of dynamical properties of systems near the second order phase transition are studied by using the continued fraction representation. It is shown that time-evolution of an observable relevant to the second order phase transition exhibits no relaxation at the critical point, It is also shown that under a certain condition the relation of the dynamic critical exponent to the exponent of the static susceptibility can be derived. As an explicit example, the relaxation function, admittance and the random forces of the transverse Ising model are exactly calculated near the critical point to be given as functions of the inverse static susceptibility. These results confirm the correctness of the general argument given above.
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  • K-Capture Probabilities and Some B(E2) Ratios in the Decay of 152Eu
    S. S. Ghumman, H. S. Binarh, H. S. Sahota, Takeki Iwashita
    1989 Volume 58 Issue 11 Pages 3921-3928
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3921
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    KX ray-gamma ray coincidence and sum coincidence methods have been used to measure the relative K-capture probabilities to 810.46, 1085.89, 1233.87, 1529.81, 1579.43 and 1649.93 keV levels in 152Sm from the decay of 152Eu. Ten weak gamma transitions not reported earlier have been identified. B(E2) ratios for six out of these and for the transitions from the states of gamma band in 152Sm compare favourably with the interacting boson model predictions.
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  • Impact Parameter Dependent Probability of Au L3-Shell Ionization by 40.7 MeV Ar Ions
    Tadashi Kambara, Tatsumi Mizogawa, Yohko Awaya, Yasuyuki Kanai, Reinho ...
    1989 Volume 58 Issue 11 Pages 3929-3935
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3929
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    The ionization probability of Au–L3 shell by 1 MeV/u Ar ions is measured as a function of impact parameter by a scattered projectile-x ray coincidence method. The result is compared with semi-classical approximation calculations with separated-atom and united-atom electron wavefunctions for the initial state of the ionized electron. It is close to or larger than the separated-atom values at impact parameter larger than the radius of Au–L shell and it approaches to the united-atom value at smaller impact parameters. This behavior is qualitatively consistent with the binding effect.
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  • Single Particle Analysis of Free-Electron Laser with Uniform Axial Electrostatic and Magnetic Fields
    Pallavi Jha, T. P. Pandya, L. M. Bali, Seema Lal
    1989 Volume 58 Issue 11 Pages 3936-3938
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3936
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    The possibility of obtaining significant FEL gain at an upshifted Larmor frequency is examined with the help of single particle analysis in the small gain per pass limit.
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  • Reflection and Transmission of Two-Dimensional Shallow Water Solitons
    Chihiro Matsuoka, Nobuo Yajima
    1989 Volume 58 Issue 11 Pages 3939-3948
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3939
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    The propagation of shallow water solitary waves has been investigated in a channel whose depth changes stepwise. A nonlinear counterpart of Snell’s law has been obtained associated with reflection and refraction of waves. The reflection and transmission coefficients of solitons as well as the number of solitons emerged have been estimated with the aid of the inverse scattering method.
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  • Transient Adjustment of a Gas Contained in a Rapidly-Rotating Infinite Cylinder
    Jun Sang Park, Jae Min Hyun
    1989 Volume 58 Issue 11 Pages 3949-3959
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3949
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    A numerical study is made of the transient flow of a gas contained in an infinite circular cylinder which impulsively starts rotating about the central longitudinal axis with angular frequency Ω. As a sequel to the previous work which reported on the early-time behavior of the flow, descriptions are given of the flows at moderate and large times leading to the steady state. Attention is confined to the situations in which the reference system Ekman number E is small, and the compressibility effect is substantial. Two types of the sidewall thermal boundary condition are considered: an isothermal wall and an adiabatic wall. Systematically-organized numerical solutions are obtained by solving the full, time-dependent, compressible Navier-Stokes equations. The details of the evolutions of the velocity, density and temperature fields are presented. The evolutionary profiles of the temperature fields show profound differences between the two sidewall thermal conditions.
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  • Method for Analyzing Nonlinear Wave Propagation and Wave-Trapping in Magnetoplasmas
    Haruichi Washimi
    1989 Volume 58 Issue 11 Pages 3960-3969
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3960
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    A new method of perturbation for the study of nonlinear wave propagation in a magnetoplasma is proposed under the condition that the dielectric tensor of the plasma changes slowly in time and space. Using this method, we derive a generalized nonlinear wave equation for the transverse waves propagating along magnetic field lines, which includes the effects due to the ponderomotive force or due to an inhomogeneity of the plasma. The physical condition is elucidated for the wave-trapping in two- or three-dimensional space which comes from a negative-pressure effect of the ponderomotive force or the inhomogeneity.
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  • A 3-D Resistive MHD Simulation Analysis of Field Reversal Control in the Reversed Field Pinch
    Akiyoshi Nagata, Hisao Ashida, Shinji Koide, Koichi Sato, Tsuneo Amano
    1989 Volume 58 Issue 11 Pages 3970-3978
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3970
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    A three-dimensional (3-D) resistive MHD simulation code under the compressibility condition has been applied to analysis of the field reversal control in the reversed field pinch (RFP). Simulation results have shown that a loss of the field reversal at the wall leads to flattening of the toroidal field profile, and also to the rapid increase of the fluctuating magnetic energy due to nonlinear tearing modes with m=1. Moreover, the fluctuating magnetic energy spectrum for the m=1 and m=2 modes rapidly broadens toward high and low n, which is caused by the (m=0; n=−1) mode. By deepening the field reversal at the wall, the reversal surface keeps away from the plasma surface, and safety factor becomes a narrow profile. As a result, a rapid growth and saturation of these tearing modes is suppressed by the field reversal control.
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  • Extension of Stellarator Approximation in Magnetohydrodynamic Equilibrium and Stability of Toroidal Helical Systems
    Jiro Todoroki
    1989 Volume 58 Issue 11 Pages 3979-3992
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3979
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    Formulation is made to solve three dimensional MHD equilibrium problem on the basis of the coordinate transformation. The three dimensional problem is divided into three steps: 1) the hyperbolic equations to determine the coordinate transformation, 2) averaged equation in two dimension, and 3) the three dimensional elliptic equation to deal with magnetic potential. The usual stellarator approximation or averaging method is regarded as the first step of the iteration prcccedure to get the solution of the full three dimensional problems. In formulating linear stability problem, the stellarator ordering is required; the resonance effect is ignored in the averaging formulation. Formulation of stability problems in the averaging method is also given, by ignoring resonance effects. Some comparison for vacuum magnetic surfaces is made to check the validity of the formulation.
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  • Stucture Determination of the Monoclinic Form of KCN
    Yukio Yoshimura
    1989 Volume 58 Issue 11 Pages 3993-3998
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3993
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    The crystal structure of the monoclinic form in the metastable phase of KCN was analyzed by X-ray diffraction method. It was found that the structure is A-base-centered monoclinic with space group A2⁄m. The K+ ions lie on the A-base-centered sheets, the C or N atoms occupy statistically on the eight equivalent positions (8j) which give a two-dimensional orientational disorder of CN− ion of which shape is of cross. The center of mass positions of the CN− ions are (0.5, 0.5, 0.0) and (0.5, 0.0, 0.5) of the monoclinic cell and lie on the {100} planes of the original cubic lattice.
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  • Electron-Ion Correlation in Liquid Sodium
    Shin’ichi Takeda, Sh\={u}zi Harada, Shigeru Tamaki, Yoshio Wased ...
    1989 Volume 58 Issue 11 Pages 3999-4006
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.3999
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    The structure factor of liquid sodium at 110°C has been determined by neutron diffraction with sufficient accuracy and compared with those obtained by X-ray diffraction. A small but clear difference in these structure factors has been found in the region Q\lesssim5 A−1, and these differences are apparently larger than the experimental errors. The ion-electron correlation function has been evaluated from this difference with the help of theoretical calculation of the electron-electron correlation function. The radial distribution function of valence electron around ions has been calculated by the Fourier transform of this function and the different features of the electron charge distribution from those in liquid polyvalent metals are also discussed.
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  • Ultrasonic Velocity and Absorption in Molten Cuprous Halides
    Shin’ichi Takeda, Yoshiyuki Shirakawa, Koh-ichi Takesawa, Sh\={u ...
    1989 Volume 58 Issue 11 Pages 4007-4011
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4007
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    The ultrasonic velocity and absorption of molten cuprous halides (CuCl, CuBr and CuI) were measured at temperatures from the melting points to about 850°C. The observed sound velocities of molten cuprous halide decrease with increasing temperature. The adiabatic compressibilities are derived from the observed sound velocities. The observed compressibility in molten CuI are larger than those in liquid CuBr and CuCl. The difference of the ultrasonic velocities in molten cuprous halides can be discussed from the viewpoint of ionicity and covalency in molten cuprous halide together with those in molten silver halide.
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  • The Sound Velocity in the Liquid Sn–Te Alloys
    Yoshimi Tsuchiya, Toshikatsu Takahashi
    1989 Volume 58 Issue 11 Pages 4012-4018
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4012
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    Sound velocity, Vs, in the liquid Sn–Te alloy has been measured up to 1000°C. The compressibility deduced from Vs and the density as a function of the concentration shows a cusp at the Te rich side of the stoichiometric SnTe. The results have been discussed in relation to the anomalous thermodynamic and electrical properties of the alloy.
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  • Renormalized Kink and Peierls Potential in a Nonlinear Lattice —Statistical Mechanical Approach—
    Toyonori Munakata, Akito Igarashi
    1989 Volume 58 Issue 11 Pages 4019-4024
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4019
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    Peierls potential for a kink in a nonlinear lattice system is investigated from a statistical mechanical point of view. A kink with phonon-dressing e.g. a renormalized kink is obtained in a self-consistent manner. Our results are compared with numerical simulations.
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  • Kink Dynamics in a Discrete Nonlinear System —The Exact Equations of Motion for Kinks—
    Akito Igarashi, Toyonori Munakata
    1989 Volume 58 Issue 11 Pages 4025-4031
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4025
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    Exact equations of motion for kinks in a discrete nonlinear system are obtained based on the Hamiltonian formalism with extra kink-degrees of freedom being compensated by the constraints among the dynamical variables. The validity of the equations is numerically confirmed.
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  • Optical Investigations of Lattice Vibrations of II–VI Compound Semiconductors
    R. K. Ram, S. S. Kushwaha, J. S. Rajput
    1989 Volume 58 Issue 11 Pages 4032-4040
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4032
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    An approximate estimate of critical point phonon frequencies has been made for ZnTe and CdTe in the frame-work of the new dynamic model [J. Phys. Soc. Jpn. 54 (1985) 617]. Maxima in the infrared absorption and/or Raman scattering experiments have been tentatively assigned in terms of lattice dynamical critical phonons. The calculated phonon frequencies show a reasonably satisfactory agreement with the available optical and neutron scattering data.
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  • Thermodynamic Investigations on the AgBr–CuBr System
    Masatoshi Saito, Haruyuki Takahashi, Shigeru Tamaki
    1989 Volume 58 Issue 11 Pages 4041-4047
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4041
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    The calculations of specific heats of (AgxCu1−x)Br were compared with experimental data taken from the literature. The negative temperature coefficients of specific heat (dCp⁄dT<0) in the δ-phase at the concentrations higher than 25 mole% CuBr were well reproduced by assuming a random distribution of cations on the octahedral and tetrahedral sites. On the basis of this disorder model, the formation energy of ions on the tetrahedral sites were determined for various compositions. It was found that the formation energy becomes lower with increasing the amount of CuBr.
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  • Effects of Impurities in Polyacetylene —Bond-Type Short-Ranged Impurities
    Kaoru Iwano, Yoshiyuki Ono, Akira Terai, Yasushi Ohfuti, Yasushi Wada
    1989 Volume 58 Issue 11 Pages 4048-4063
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4048
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    Effects of short ranged bond-type impurities in polyacetylene are investigated numerically, using a generalized Su-Schrieffer-Heeger’s model. Soliton formation and pinning by impurities are studied. Infrared activities are analyzed with relevant phonons. Similarities and differences from site-type impurities are pointed out. It is striking to find that there may be two types of exotic “solitons”. One is a kink in the bond alternation configuration which carries neither charge nor spin. The other is a soliton with a fractional charge and a fractional spin, which appears in a situation where the polaron solution is stable in the absence of impurities. The stabilization of the exotic solitons is associated with the fact that the particle-hole symmetry still holds in the presence of the bond-type impurities.
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  • Theory of Valence-Fluctuating Tm Impurities. I
    Tetsuro Saso
    1989 Volume 58 Issue 11 Pages 4064-4077
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4064
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    A new formalism is presented for describing mixed valent Tm impurities fluctuating between two magnetic configurations. Based on the self-consistent perturbation scheme, the present formalism incorporates not only the valence fluctuation between 4f12 and 4f13, but also the multiscattering process of 4f13 and a conduction electron, yielding a singlet bound state. Thus the ground state is a Kondo singlet, which however is different from the ordinary Kondo state and conceptually new in that the length of the local moment of the impurity is fluctuating between the two values j=6 and J=7⁄2. Numerical calculations are presented for the spectral distribution function of these states. Systematic study of the Kondo temperature TK yields that TK is substantially low when the number of f electrons is close to 12. Contribution of the above scattering processes to the f-electron spectral function and the magnetic susceptibility is also disscussed.
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  • A New Phase Transition of α-Ce3Al Due to the Spin Fluctuation? —the Partial Substitution of La and Y for Ce—
    Junji Sakurai, Yoshio Murashita, Yuji Aoki, Toshizo Fujita, Toshiro Ta ...
    1989 Volume 58 Issue 11 Pages 4078-4085
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4078
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    The measurements of the X-ray powder diffraction, the magnetic susceptibility, the electric resistivity, the thermopower and the specific heat were carried out for the sample of α-Ce3Al and the substituted systems of La and Y for Ce. In α-Ce3Al, the first order phase transition at Ts∼100 K is found to be accompanied with a decrease of the unit cell volume of the low temperature phase by an amount of 1.8%, without changing the crystal structure of a hexagonal Ni3Sn type. The substitution of either La or Y for Ce leads to the decrease of Ts, indicating the transition to be dependent on the Ce concentration due to a cooperative nature between the Ce 4f electrons. The transition closely associated with the valence change of Ce is discussed in connection with the spin fluctuation.
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  • Quantitative Analysis of the Role of Contacts in the Measurements of Integral Quantum Hall Effects
    Hiroshi Hirai, Susumu Komiyama, Shigehiko Sasa, Toshio Fujii
    1989 Volume 58 Issue 11 Pages 4086-4092
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4086
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    Heterostructure (GaAs/AlGaAs) Hall-bar devices with a short cross gate are studied in a quantum Hall regime. Anomalous longitudinal resistances and deviations of the Hall resistance from an expected quantized value are quantitatively analyzed in terms of properties of contacts. Reverse-field reciprocity symmetry is observed to demonstrate symmetric properties of contacts.
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  • Thermoelectric Power and an Order-Parameter Associated with the Phase Transition at 180 K of the Organic Metal, (DMET)2Au(CN)2
    Kazuya Saito, Hiroyuki Kamio, Yoshiaki Honda, Koichi Kikuchi, Keiji Ko ...
    1989 Volume 58 Issue 11 Pages 4093-4097
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4093
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    The thermoelectric power of (DMET)2Au(CN)2 was measured between liquid nitrogen and room temperatures. The metallic nature and the hole-like character of the conduction carriers were confirmed. A small anomaly due to the phase transition at 180 K was detected in the temperature dependence. A tentative estimate is made of an order-parameter associated with the phase transition.
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  • High Field Magnetoresistance and de Haas-van Alphen Effect in LaNi
    Kunihiko Maezawa, Takahiro Kat\={o}, Yosikazu Isikawa, Kiyoo Sat\={o}, ...
    1989 Volume 58 Issue 11 Pages 4098-4103
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4098
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    The transverse magnetoresistance and de Haas-van Alphen (dHvA) effect in LaNi have been studied in the fields up to 150 kOe. It was found from the magnetoresistance that the Fermi surface of LaNi contains two open surfaces elongated along the b- and c-axes. Many dHvA branches with the frequencies ranged from 7×105 Oe to 1.5×108 Oe were found in the fundamental planes. The cyclotron effective masses range from 0.4m0. to 3.3m0.
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  • Bunching of Carriers in Momentum Space under Crossed Magnetic and Intense Microwave Fields in Semiconductors
    Tatsumi Kurosawa, Yoshihide Kosano
    1989 Volume 58 Issue 11 Pages 4104-4115
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4104
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    The motion of a carrier in momentum space is examined in detail for the case that an intense microwave electric field and a static magnetic field perpendicular to it are applied to semiconductors in which the predominant scattering process is the optical phonon emission. The motion changes the type in a systematic way depending on the strengths of the fields. Particularly in intermediate magnetic field range, the motion rapidly converges to a terminal motion independent of the initial condition, leading to a bunching of the carriers in the momentum space. The convergence becomes slow as the magnetic field is decreased. In strong magnetic fields, the motion becomes of long period or chaotic. The type of the motion changes periodically with the electric field. The calculation is carried out for two waveforms, square and sinusoidal. The results are very similar to each other as for the bunching, implying its generic property.
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  • Unconventional Superconducting Class in a Heavy Fermion System UPt3
    Kazushige Machida, Masa-aki Ozaki, Tetsuo Ohmi
    1989 Volume 58 Issue 11 Pages 4116-4131
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4116
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    The origin of the double transition phenomenon recently found in a typical heavy Fermion material UPt3 is investigated. It is shown group-theoretically solely on the basis of the known symmetries that there exists a non-trivial coupling term between the preexisting spin density wave order parameter and the superconducting pairing function belonging to a degenerate representation with internal degree of freedom. This coupling ultimately leads to the Tc splitting. Superconducting properties associated with this unconventional pairing function, including the phase diagram, are discussed both in the absence and presence of an applied field. Several experiments are proposed to test the present theory, in particular, the field dependence of the double transition is crucial to identify the symmetry of the pairing function. The existing data are most consistent with those in the two-dimensional representations E1g or E1u of the hexagonal symmetry. The possibility of similar phenomenon in other heavy Fermion systems is also examined.
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  • Magnetic Relaxation of High Tc Superconducting Thin Films
    Shin-ichiro Hatta, Hideaki Adachi, Yo Ichikawa, Shigenori Hayashi, Shi ...
    1989 Volume 58 Issue 11 Pages 4132-4138
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4132
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    The magnetic relaxation of high Tc superconducting thin films was studied. In the n type NdCeCuO film, the significantly large relaxation was observed even in a low temperature region below 20 K, as compared with other p type oxide superconducting films. In order to analyze the data, a phenomenological model was presented. In this model, we used the time variable pinning potential barrier for the flux creep, combined with a classical relaxation equation. The activation energy defined as height of potential barrier at t=∞ can be calculated to be 0.01 eV, 0.12 eV and 0.19 eV for NdCeCuO, TlBaCaCuO and ErBaCuO films, respectively.
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  • Electron Spectroscopy of Nd2−xCexCuO4−y (x=0, 0.15, and 0.23) Thin Films
    Shigemi Kohiki, Shigenori Hayashi, Hideaki Adachi, Shin-ichiro Hatta, ...
    1989 Volume 58 Issue 11 Pages 4139-4146
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4139
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    Electron spectroscopy of Nd2−xCexCuO4−y (x=0, 0.15, and 0.23) thin films prepared by rf magnetron sputtering and successive annealing under a reducing condition was carried out. The films showed semiconducting, superconducting, and metallic behaviors according to x. The X-ray photoelectron and Auger electron spectra revealed that the electrons doped by replacing Nd3+ with Ce4+ were present in both the CuO2 plane and the Nd layer of the Nd2CuO4 crystal. The Cu valence was found to be 1+ for the superconducting x=0.15 film by the photoelectron and Auger electron spectra. Udd=9 eV and Upp=6 eV were obtained from the CuL3VV and OKVV Auger electron spectra for the x=0.15 film.
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  • Consistent Solutions of BCS-Gap Equation for the Hole-Pairing Mechanism by the Exchange of Soft-Magnons in a Frustrated Heisenberg Square-Lattice System
    Atsushi Ohta, Masaaki Nojima, Toshihiko Suzuki, Yuhei Natsume
    1989 Volume 58 Issue 11 Pages 4147-4155
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4147
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    The pairing mechanism for doped holes to d3z2−r2 orbitals of Cu2+ ions on a CuO2 plane is proposed so as to make clear the property of superconducting phases of high-Tc superconductors where coexistence of the antiferromagnetic ordering has been recently reported. The pairing is made by the exchange of antiferromagnetic magnons for dx2−y2 spins on CuO2 plane. Here, the frustration introduced by the second nearest neighbor antiferromagnetic exchange interaction between Cu2+ ions plays an significant role. The BCS-type gap equation is derived and self-consistent solutions are obtained numerically for various symmetries. Among them, the gaps for s and dxy symmetries are discussed in detail. By the essential contribution of the frustration, the gap can be formed even for the intermediate coupling region.
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  • Auxiliary-Particle Theory of Strongly Correlated Systems
    Fusayoshi J. Ohkawa
    1989 Volume 58 Issue 11 Pages 4156-4167
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4156
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    The Hubbard model with strong correlation is investigated in an auxiliary boson-fermion Hamiltonian, where electrons are described by fermionic pair-excitations of auxiliary particles. Auxiliary particles are localized because of a local gauge symmetry, which is required to guarantee the equivalence between the Hubbard model and the auxiliary-particle Hamiltonian. The density of states of electrons has a double-peak structure in nearly-half filled cases. The main band is broad and deep, and it is consistent with the alloy analogy of the Hubbard model. The other is narrow and at the top of the main band, where the chemical potential lies. The narrow peak can be interpreted in terms of the formation of heavy quasiparticles or heavy electrons. The mass enhancement factor of heavy electrons is consistent with the Gutzwiller variational treatment of the Hubbard model.
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  • Magnetic Properties and Superconductivity of the Strong Coupling Hubbard Model
    Hiroshi Shimahara, Susumu Misawa, Satoshi Takada
    1989 Volume 58 Issue 11 Pages 4168-4183
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4168
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    The t-J model, which in the case of J<<t can be derived from the strong coupling Hubbard model, is studied in the improved Hubbard III approximation. It is found that the magnetic properties change from that of localized spin systems to that of itinerant electron systems. In the half-filled limit, the susceptibility is shown to reduce to the Curie-Weiss form in the mean field approximation on the exchange term of the Hamiltonian. It is also found that the antiferromagnetic transition temperature decreases very rapidly with slightly hole-doping of the half-filled case. The superconductivity is also examined within a similar approximation. The relation to the oxide high Tc superconductors is discussed.
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  • Hole Propagation in a 2D Quantum Spin-1/2 Antiferromagnet —Effect of Local Spin Relaxation—
    Hirokazu Tsunetsugu, Yoshinori Takahashi
    1989 Volume 58 Issue 11 Pages 4184-4199
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4184
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    We discuss density of states of a hole doped into a spin-1/2 Heisenberg antiferromagnet (AF). From the multi-spin correlation functions, moments of the density of states are estimated up to the 8-th order taking into account the effect of local spin relaxation around a hole. We show the density of states for AF shows divergent behavior near the band edge.
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  • Magnetic Moment Anomaly and Reentrant Spin-Glass Transition in Mn-Rich bcc Cr–Mn Alloys
    Shuzo Kawarazaki, Katsumi Yasuda
    1989 Volume 58 Issue 11 Pages 4200-4204
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4200
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    Magnetic properties of bcc Cr1−xMnx alloys with x up to 0.69 have been studied by means of neutron diffraction and susceptibility measurements. The average magnetic moment of the constituent atoms shows an abrupt increase in magnitude in the region 0.5<x<0.69. The reduction of the sublattice magnetization of the x=0.69 alloy with increasing temperature is much faster than that of the x=0.20 alloy. These observations are indicative of the existence of two electronic states of the bcc Mn with different magnetic moment. The alloys with x>0.4 show a reentrant spin-glass transition around 40 K.
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  • Critical Behavior of Hyperfine Field at Reentrant Transition in Au(Fe)
    Kunio Niwa, Yutaka Nakai, Yukito Furukawa
    1989 Volume 58 Issue 11 Pages 4205-4210
    Published: November 15, 1989
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    DOIhttps://doi.org/10.1143/JPSJ.58.4205
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    In the reentrant spin-glass region of Au(Fe) alloys, the transverse component of the mean squared hyperfine field was measured by means of Mössbauer measurements. The temperature variation is expressed by a simple power law as (Tf−T)βhf, where Tf and βhf are the reentrant transition temperature and the exponent, respectively. The obtained value of the exponent, 2.4, is compared with the critical exponent of a spin-glass order parameter, βSG.
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  • A Phenomenological Theory of Structural Phase Transitions in Zirconia
    Yoshihiro Ishibashi, Vladimir Dvo\'{r}\v{a}k
    1989 Volume 58 Issue 11 Pages 4211-4214
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4211
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    The structural phase transitions in zirconia ZrO2 are interpreted phenomenologically, based upon the Landau-type thermodynamic potential derived on the consideration of the change of translational as well as rotational symmetry of the unit cell. The difference between Chan’s model and ours is mentioned.
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  • Experimental Studies of Phase Transitions in Betaine Phosphate
    Kazuhiro Hara, Hiroshi Umeda, Yoshihiro Ishibashi, Ikuo Suzuki
    1989 Volume 58 Issue 11 Pages 4215-4221
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4215
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    Successive phase transitions in betaine phosphate were studied by measuring the temperature and pressure dependence of dielectric constants, and by observing the temperature dependence of the Raman spectra. The experimental results confirmed two low temperature transitions. The phase sequence is phenomenologically interpreted with the Landau-type thermodynamic potential.
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  • Optical Properties of Electron Trapped Center in Layered Ionic Crystals (CH3NH3)2CdCl4 and (C2H5NH3)2CdCl4 Irradiated with X-Rays at 15 K
    Takehisa Yoshinari, Tomochika Matsuyama, Hitoshi Yamaoka, Kiyoshi Aoya ...
    1989 Volume 58 Issue 11 Pages 4222-4227
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4222
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    New optical absorption bands (IR bands) were found at around 10∼20 kcm−1 besides absorption band of Cl2− molecular center in two-dimensional crystals of (CH3NH3)2CdCl4 and (C2H5NH3)2CdCl4 irradiated with X-rays at 15 K. The absorption intensities increase with the X-ray dosage in proportion to that of the Cl2− center and decrease at temperatures higher than 25 K for (CH3NH3)2CdCl4 and 35 K for (C2H5NH3)2CdCl4 accompanying the decrease of Cl2−. The both bands are also bleached by the light irradiation on the IR bands at 15 K. The IR bands are assigned to an electron center where an electron is trapped by an alkylammonium head in the neighborhood of a Cl− vacancy.
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  • Molecular Luminescence from Electron-Irradiated Alkali Halides
    Masao Kamada, Hiroaki Yamamoto, Edward T. Arakawa
    1989 Volume 58 Issue 11 Pages 4228-4234
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4228
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    The ultraviolet (uv) emission composed of vibronic lines emitted from electron-irradiated alkali halides was investigated. It was observed only from the surface layers of NaCl and KCl among various alkali halides (alkali=Li, Na and K; halogen=F, Cl and Br, except LiBr). It was also found that the intensity of the uv emission increases as the irradiation dose is increased, and that the uv emission spectra of electron-irradiated NaCl and KCl coincide well with those of X-ray irradiated NaCl:CN and KCl:CN, respectively. These results suggest that the uv emission is attributed to CN− introduced from the ambience into the surface layer of the crystals during electron irradiation. The difference in the appearance of the uv emission among alkali halides is explained in terms of the size of the halogen-ion vacancy and the emission mechanism.
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  • The Irregular Behavior of a Counter-Ion Density Described by the Application of the Two-Dimensional Poisson-Boltzmann Equation
    Tetsuo Kaneko
    1989 Volume 58 Issue 11 Pages 4235-4250
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4235
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    The density of a counter-ion atmosphere, as described by the application of the two-dimensional Poisson-Boltzmann equation, around an ionized cylindrical model-molecule, can change irregularly. This cylindrical model-molecule is immersed in an aqueous solvent of infinite volume. Its radius (a), the packing density (ng) of charged groups in it, and temperature are parameters for determing the counter-ion density. It is found that as a or ng increase, the counter-ion density being zero at small values of a or ng increases irregularly, even at constant temperature. If temperature rises, it is found that the counter-ion atmosphere around the ionized cylindrical model-molecule may be subject to a transition from a state of accumulated counter ions to one in which the accumulation of counter ions is lost, even though a and ng are constant.
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  • A Note on the Surprisal Analysis of Molecular Fragments Produced in a Two-Step Dissociation
    Kazuhiro Kanda, Kiyohiko Someda, Haruhiko Ito, Kaoru Suzuki, Tamotsu K ...
    1989 Volume 58 Issue 11 Pages 4251-4252
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4251
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  • Relative Diffusion of a Pair of Fluid Particles in Turbulence
    Hajime Nakao, Tsutomu Imamura
    1989 Volume 58 Issue 11 Pages 4253-4254
    Published: November 15, 1989
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4253
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  • Magnetism of Fe/Dy Multilayers Studied from Mössbauer Spectroscopy
    Teruya Shinjo, Kenichi Yoden, Nobuyoshi Hosoito, Jean-Pierre Sanchez, ...
    1989 Volume 58 Issue 11 Pages 4255-4256
    Published: November 15, 1989
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.58.4255
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