Journal of the Physical Society of Japan
Online ISSN : 1347-4073
Print ISSN : 0031-9015
ISSN-L : 0031-9015
Volume 66, Issue 3
Displaying 1-50 of 62 articles from this issue
  • Akira Fujii
    Subject area: Mathematical methods in physics.
    1997 Volume 66 Issue 3 Pages 507-510
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    We consider the soliton solutions in the one- and (1+1)-dimensional Toda lattice models with a boundary. We make use of the solutions already known on a full line by means of Hirota's method. We explicitly construct the solutions satisfying the boundary conditions. With these classical solutions, we can understand the Z-symmetric boundary condition introduced by two-soliton solutions in a natural way.
    Download PDF (324K)
  • Akira Onuki
    Subject area: Statistical physics and thermodynamics.
    1997 Volume 66 Issue 3 Pages 511-513
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    An intuitive derivation of the critical bulk viscosity is presented for one- and two-component fluids in a general form. In addition to critical acoustics, we examine slowly relaxing pressure, temperature, and density relaxations after stepwise volume or pressure changes. Their measurement will yield information of the timecorrelation function on the diagonal part of the stress.
    Download PDF (244K)
  • Shin–ichi Tadaki
    Subject area: Statistical physics and thermodynamics.
    1997 Volume 66 Issue 3 Pages 514-517
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The distribution of jam clusters in a two-dimensionalcellular automaton model of traffic flow with openboundaries is investigated by computer simulation. The sizedistribution of jam clusters obeys the power law of theinjection rate in the high-injection-rate region. The totalnumber of unmoved cars in jam clusters shows a sharptransition at the critical injection rate and can be anadequate order parameter describing the phase transitionwith the emergence of a traffic jam.
    Download PDF (311K)
  • Tatsunari Sakurai, Hidetoshi Miike, Etsuro Yokoyama, Stefan C. Mü ...
    Subject area: Statistical physics and thermodynamics.
    1997 Volume 66 Issue 3 Pages 518-521
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Spiral patterns are representative dissipative structures that can be observed in reaction-diffusion systems such as Belousov-Zhabotinsky (BZ) reactions. We found periodic initiation of moving structures of convection from the collision line of the fronts of two spiral patterns triggered in a shallow layer of a BZ solution. The waves of convection propagated toward the respective centers of the spirals, and were annihilated there. The flow direction of the convection waves reversed every 15--16 s. These curious pattern dynamics can be interpreted as a demonstration of a hierarchical and/or a functional order in the complex system of reaction, diffusion and convection.
    Download PDF (699K)
  • Susumu Kinpara
    Subject area: Nuclear reactions and scattering: general.
    1997 Volume 66 Issue 3 Pages 522-524
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Fragmentation reaction cross sections at relativistic energies are investigated using a phenomenological approach. Equations are obtained by a geometrical treatment in the framework of classical dynamics, in which the impact parameter is introduced. A numerical solution is obtained for the 56Fe + 12C system at 600 MeV/nucleon incident energy. It is shown that the predicted mass number distribution of fragments reproduces well the experimental data. The Coulomb energy term in the mass formula affects the nuclide dependence of cross sections to a favorable direction.
    Download PDF (249K)
  • Masanori Eda, Jun–ichi Sakai, Jie Zhao, Torsten Neubert, Mitsuhi ...
    Subject area: The physics of plasmas and electric discharges.
    1997 Volume 66 Issue 3 Pages 525-528
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Simulations using a two-dimensionalelectromagnetic and relativistic particle code show that high-frequencyLangmuir waves can be generated by aplasma maser mechanism from low-frequency whistlerwaves excited by electron temperature anisotropy. It is confirmed that the plasma maser mechanism does not requirean electron beam component for the generation of high-frequency Langmuirwaves. We are forced to reconsider the emission mechanism of Langmuirwaves observed in space plasmas.
    Download PDF (437K)
  • Ken Yokoyama, Hidetoshi Fukuyama
    Subject area: Electron states in condensed matter.
    1997 Volume 66 Issue 3 Pages 529-532
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The real part of the self-energy of interacting two-dimensional electronshas been calculated in the t-matrix approximation.It is shown that the forward scattering results in an anomalous termleading to the vanishing renormalization factor of the one-particleGreen function, which is a non-perturbative effect of the interaction U.The present result is a microscopic demonstration of the claim byAnderson based on the conventional many-body theory.The effect of the damping of the interacting electrons, which has been ignored in reaching above conclusion, has been briefly discussed.
    Download PDF (287K)
  • Shin–ichiro Ito, Keiya Shirahama, Kimitoshi Kono
    Subject area: Electronic transport in condensed matter.
    1997 Volume 66 Issue 3 Pages 533-536
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Edge magnetoplasmons on a liquid helium surface have been studiedfrom 90 to 1400 mK and for magnetic fields up to 6.4 T.The magnetoconductivity σxx is obtained from the damping coefficient.Above 900 mK, the present σxx result agrees well with the previousresult obtained by Dykman et al /. [Phys. Rev. Lett. 70 (1993) 3975].Below 700 mK, σxxis proportional to 1/√T, where T is temperature, and almost independent of the magnetic field.The temperature dependence agrees well with theory, whereas the magnetic field dependence does not.Nonlinear narrowing of the resonance linewidth is observed.
    Download PDF (382K)
  • Yositake Takane
    Subject area: Electronic transport in condensed matter.
    1997 Volume 66 Issue 3 Pages 537-540
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The Josephson current through a one-dimensional (1D) interacting electron system of length L coupled with two superconductors is studied in the presence of a barrier potential at the junction interfaces. The 1D system is treated within the framework of the Tomonaga-Luttinger liquid, in which the interaction is characterized by correlation exponents Kρ and Kσ. We pay attention to the influence of Andreev reflection, which modifies the low-energy property of the 1D electron system near the junction interfaces. It is found that the critical current at low temperatures decays with increasing L as jc∝ (1/L)2/K_ρ-1, which is in striking contrast to the previous result jc∝ (1/L)1/K_ρ+K_σ-1, obtained by Fazio et al. taking no account of the influence of Andreev reflection.
    Download PDF (348K)
  • Hiroshi Shimahara
    Subject area: Superconductivity.
    1997 Volume 66 Issue 3 Pages 541-544
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The possibility of the existence Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state in quasi-low-dimensional organic superconductors is discussed. The critical field and the wave number q of the spatial oscillation are calculated on the basis of a tight binding model of κ-[BEDT-TTF]_{2I3}, as an example. The critical fields Hc at T=0 are estimated to be roughly 1.5, 2, and 2.5 times the Pauli paramagnetic limit HP for s-wave, dxy-wave, and dx2-y2-wave FFLO states, respectively. We discuss which properties of the structure of the Fermi surface enhance the critical field and are relevant to the direction of q. We show that the number of the lines on the displaced Fermi surfaces due to the Zeeman energy which simaltaneously touch by translation p → p+q are important in addition to the curvature of the Fermi surface and the density of states.
    Download PDF (393K)
  • Tetsuo Ohama, Masahiko Isobe, Hiroshi Yasuoka, Yutaka Ueda
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 545-547
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    23Na NMR spectrum measurementsin a spin-Peierls system, NaV2O5, are presented.Below the spin-Peierls transition temperature (Tsp), two distinct sites of Na appear, confirming the structural phase transitionat Tsp.The orbital susceptibility was evaluatedusing the temperature dependence of the 23Na NMR shift;it is suggested that the orbital susceptibility changes near Tsp.The temperature dependence of the spin susceptibility obeysan activation law below --20 K with a gap of 98 K.
    Download PDF (271K)
  • Masafumi Sera, Seiichi Itabashi, Satoru Kunii
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 548-551
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Thermal expansion and longitudinal magnetostriction along the ‹ 001› direction Δl/l‹ 001› of NdB6 have been measured in the magnetic field H along the z axis (‹ 001› direction) up to 8, T. Below the Néel temperature TN, accompanying the spin-flop transition or domain rotation at 0.5, T, the z axis shrinks greatly. The thermal expansion in H=2.1, T, where the ordered moment is perpendicular to H, shows that the shrinkage of the z axis becomes smaller with increasing temperature and disappears at TN. The results were analyzed using a molecular field approximation and it was shown that it is necessary to introduce the ferro-quadrupolar interaction K3 with a Γ3 symmetry in NdB6. The difference in the thermal expansion in the paramagnetic region between CeB6 and NdB6 is discussed from the standpoint that there exists large antiferro-quadrupolar short-range ordering in CeB6.
    Download PDF (383K)
  • Shintaro Nakamura, Osamu Suzuki, Terutaka Goto, Shinichi Sakatsume, Ta ...
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 552-555
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Low-temperature specific heat and electric resistivity of the dense Kondo compound Ce0.5La0.5B6 have been measured. The specific heat for H=0 shows a broad peak at around 0.9, K corresponding to the Kondo effect. No indication of magnetic or quadrupolar phase transition is observed down to 100, mK for H=0. Very large specific heat coefficients of γ =1.8, J/K2, mol and β =2.9, J/K4, mol for H=0 indicate the Kondo singlet ground state without long-range ordering.
    Download PDF (328K)
  • Yutaka Moritomo, Hideki Kuwahara, Yoshinori Tokura
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 556-559
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Effects of hydrostatic pressure on the magnetic and transport properties of R1-xSrxMnO3 have been investigated with systematic variation of the one-electron bandwidth (W) of a conduction electron, as well as of the doping level (x).The positive pressure coefficient (dlnTC/dP) of the Curie temperature is observed for all the compounds, and its absolute value increases with decrease of W, or equivalently, TC.We have derived a nearly x-independent empirical relation between the coefficient and TC in the lightly doped region (x≤ 0.4).The coefficients at x≈1/2, however, are found to deviate from the above relation due to competing antiferromagnetic and/or charge-ordering interaction.
    Download PDF (347K)
  • Kunitomo Hirai
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 560-563
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The electronic structure of the spin-density-wave state in chromium is calculated by means of the first-principles Korringa-Kohn-Rostoker Green function method within the framework of the local spin density functional formalism.Results of the calculation are found to be in good agreement with those of experiments concerning the magnetism in spin-density-wave chromium, that is, the amplitude of the fundamental wave and the ordering wave vector.The amplitudes of the harmonics of the spin density wave and concomitant charge density wave as well as the hyperfine field at a chromium nucleus are furthermore investigated.
    Download PDF (380K)
  • Hirotaka Manaka, Isao Yamada, Kentaro Yamaguchi
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 564-567
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    On measuring the dependence of the magnetic susceptibility of (CH3)2CHNH3CuCl3 on the temperature, we find that this compound forms ferromagnetic andantiferromagnetic alternating linear chains with S=1/2. The magneticsusceptibilities observed in external fields applied along threedifferent surfaces of an as-grown single-crystal sample show broad peaksat around 24 K and steeply decrease to zero with further decreasesin temperature toward 0 K. Two types of superexchange interactions defined in the Hamiltonian\cal H= -2J1∑S2i·S2i+1 - 2J2∑S2i· S2i-1 are determined to beJ1/k=-23.5 K and J2/k=+54.1 K, which indicates that a pair offerromagnetically coupled spins behaves as a spin of S=1 and thusthis compound is regarded as antiferromagnetic linear chains with S=1. The present system can therefore be discussed in terms of the Haldane conjecture for integer spins. The energy gap is estimated to be 17.1-- 18.1 K.
    Download PDF (375K)
  • Masatoshi Imada, Youichirou Iino
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 568-571
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    We study effects of interladder coupling on critical magnetic properties ofspin ladder systems doped with small concentrations of nonmagneticimpurities, using the scaling theory together with quantum Monte Carlo (QMC) calculations. Scaling properties in a wide region inthe parameter space of the impurity concentration x and theinterladder coupling are governed by the quantum critical point (QCP) of the undoped system for the transition between antiferromagnetically orderedand spin-gapped phases. This multi-dimensional and strong-coupling region has characteristic power-law dependences on x for magnetic propertiessuch as the Néel temperature. The relevance of this criticality forunderstanding experimental results of ladder compounds is stressed.
    Download PDF (413K)
  • Masami Tatsuno, Yoji Aizawa
    Subject area: Biophysics.
    1997 Volume 66 Issue 3 Pages 572-575
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    We theoretically investigate long-term potentiation (LTP)in the hippocampus using a simple model of a neuron stimulated by three differenttime-structured input signals (regular, Markov, andchaotic). The synaptic efficacy change is describedtaking into account both N-methyl-D-aspartate (NMDA) and non-NMDAreceptors. The experimental results are successfullyexplained by our neuron model, and the remarkable fact thatthe chaotic stimuli in the nonstationary regime produce thelargest LTP is discussed.
    Download PDF (392K)
  • Masataka Iwao, Ryogo Hirota
    Subject area: Mathematical methods in physics.
    1997 Volume 66 Issue 3 Pages 577-588
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The multisoliton solution to a system of nonlinear partial differential equations which is expressed by \frac∂ v_i∂ t + 6\left(∑_1 ≤ j < k ≤ N cjk v_j v_k\ ight) \frac∂ v_i∂ x+ \frac∂ 3 v_i∂ x3=0, for i=1, 2, …, N where the coefficients cjkare arbitrary constants, is expressed by the pfaffians.
    Download PDF (432K)
  • Masakazu Ichiyanagi
    Subject area: Statistical physics and thermodynamics.
    1997 Volume 66 Issue 3 Pages 589-597
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The kinetic and statistical explanations of the second law of thermodynamics is examined in the region of extended irreversible thermodynamics. The thermodynamical entropy is identified with the entropy obtained by the maximum entropy procedure with constraints. The differential of the thermodynamical entropy is exact in the Gibbs space of fundamental variables. It is shown that irreversibility in mesoscopic levels is necessary but not sufficient for the entropy to increase. Here, irreversibility is expressed in terms of the Boltzmann equation or in terms of the Markovian master equation of the dynamical semi-group theory. The difference between the H-theorem and the second law is clearly demonstrated in the extended Gibbs space. In addition, the relative entropy is considered as an entity to connect the H-theorem with the second law.
    Download PDF (829K)
  • Atsushi Nomura, Hidetoshi Miike, Tatsunari Sakurai, Etsuro Yokoyama
    Subject area: Statistical physics and thermodynamics.
    1997 Volume 66 Issue 3 Pages 598-606
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Numerical experiments on the Oregonator modelof the Belousov-Zhabotinsky reaction with 2 variables(activator and inhibitor) are carried out.Influences of an inhibitory diffusion coefficient andinhibitory initial condition (concentration)on its pattern dynamicsare studied for several values of a stoichiometric factor of the model.As a result, several pattern formation processessuch as decrementally propagating waves and self replicating processesare found by changing the initial condition of the inhibitorand the stoichiometric factor under the Turing instability.In the self replicating process, new pattern dynamics acting as birth and death of waves is also found.
    Download PDF (807K)
  • Norio Inui, Genichi Komatsu, Koichi Kameoka
    Subject area: Statistical physics and thermodynamics.
    1997 Volume 66 Issue 3 Pages 607-612
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Pair-correlation function of the random diode-insulation network on a square lattice is obtained by the Monte Carlo simulation.Each bond is occupied by one of a positive diode, a negative diode and an insulation with probability p+, p- and 1-p+-p-, respectively.We define positive diodes to be transmitting either upward or to the rightand vice versa for negative diodes.This system exhibits continuous phase transitions signaling the appearance of an infinite self-affine cluster. We estimate the critical points and critical exponents by the time-dependent simulation and find the pair-correlation function at the critical point ischaracterized by the same exponent with fully directed percolation model.
    Download PDF (370K)
  • Hideki Nishizawa, Takashi Nakayama
    Subject area: Optics.
    1997 Volume 66 Issue 3 Pages 613-617
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Magneto-optic effect on the photonic band structure is investigated by the numerical calculation. When the magneto-optic anisotropy is applied to photonic crystals, the energetically-degenerate electromagnetic waves propagating along the anisotropy direction show the Faraday effect, as in an uniform dielectric system. On the other hand, the electromagnetic waves, which are not degenerate and are propagating perpendicular to the anisotropy direction, also show the magneto-optic effect similar to the Faraday one and its magnitude is propotional to the square of the magneto-optic anisotropy, being quite different from the case in uniform dielectrics. The origin of such effect is shown being intrinsic to the photonic band structures, by using the group and perturbation theories.
    Download PDF (391K)
  • Nirmal C. Sacheti, Pallath Chandran
    Subject area: Mechanics, elasticity, and rheology.
    1997 Volume 66 Issue 3 Pages 618-622
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The existence of similarity solutions for the steady three-dimensional boundary layer flow of a viscoelastic fluid has been investigated. It has been shown that similarity solutions exist for two mainstream flow patterns which correspond to the flow near a stagnation point. The non-linear boundary value problem governing one of these stagnation point flows has been solved numerically combined with a perturbation approach. It is found that the effects of non-Newtonian parameters are to increase the velocity in the boundary layer. Some relevant particular cases have also been discussed.
    Download PDF (375K)
  • Hiroshi Amemiya, Noboru Yasuda
    Subject area: The physics of plasmas and electric discharges.
    1997 Volume 66 Issue 3 Pages 623-632
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The parallel-plate RF discharge in oxygen has been investigated in the pressure between 10-3 and 1, Torr. The discharge mechanism is considered by comparing the electron energy distribution f(E) in O2 and N2 discharges. In O2, the low energy part of f(E) becomes deficient; a broad peak of thermal electrons appears to be shifted into the medium energy range; and the population of a higher energy group of electrons coming from the cathode sheath is less than that of N2 discharge. These are related to the negative ion formation in O2.Negative ions in the discharge in O2 are measured not only by the probe but also by using the laser photodetachment technique. The result of measurements have revealed that optimum RF power and pressure to make the negative ion density maximum exist while positive ions increases with the RF power.
    Download PDF (901K)
  • Masatoshi Saito, Changyong Park, Kazuhiko Omote, Kazumasa Sugiyama, Yo ...
    Subject area: Structure of liquids and solids; crystallography.
    1997 Volume 66 Issue 3 Pages 633-640
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The individual partial structural functions of molten CuBr have been estimated from the anomalous X-ray scattering (AXS) measurements. This data processing includes the help of the reverse Monte Carlo (RMC) simulation technique. The cation-cation structure factor of aCuCu(Q) was found to be rather structureless and the closest Cu--Cu distance in molten CuBr was significantly smaller than that for Br--Br, indicating the like-ion penetration into the first unlike-ion coordination shell, similar to the molten CuCl case. It is then suggested that a disordered close packing of Br- ions where Cu+ ions meander so as to take strongly disordered distribution by penetrating through the tetrahedral holes.
    Download PDF (679K)
  • Tatsuhiro Yogi
    Subject area: Structure of liquids and solids; crystallography.
    1997 Volume 66 Issue 3 Pages 641-648
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    We give the results of a computer simulation of fluid hydrogen chloride for general states along the liquid-vapor coexistence line. We used the intermolecular potential functions only of the separation of chlorides of molecules and an electric dipole interaction which has an orientational dependence.
    Download PDF (532K)
  • Yousuke Watanabe, Akira Sakai, Toshio Sakurai
    Subject area: Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties).
    1997 Volume 66 Issue 3 Pages 649-652
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    A new method for determining the lattice parameter using atomic beam diffraction is described. Using this method, we have measured the temperature dependence of the lattice parameter of LiF(001). It was found that the value of the surface thermal expansion coefficient is higher by a factor of 3.6 than the bulk value for temperatures up to 180°C.
    Download PDF (342K)
  • Tokihiro Takizawa, Katsuyuki Naito, Akihiro Tohsaki
    Subject area: Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties).
    1997 Volume 66 Issue 3 Pages 653-657
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Image of a liquid film forming on a ring frame attached to a DuNoüysurface tensiometer was photographed with a high-speed motion picturecamera. Pure water and an aqueous solution with a surfactant were used asthe liquids. The formation process and the oscillation of the film werecontinuously recorded. Observation of the oscillations enabled us toestimate gravitational deflection of the film and the value of thesurface tension.
    Download PDF (1385K)
  • Yasuhiro Kamada, Masaaki Matsui
    Subject area: Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties).
    1997 Volume 66 Issue 3 Pages 658-663
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    We have studied structural change of MBE grown Ni/Fe(001) and Cu/Fe(001) thin films using RHEED and X-ray diffraction measurements. Epitaxial bct-Ni film is grown initially up to 3 ML, then it changes to reconstructed c(2×2)-like structure for thicker film. 200 ML thick Ni film annealed at 520 K shows the clear formation of twinned domains of fcc-Ni {110}. The structural change of Cu films exhibits almost the same as Ni, except that it maintains bcc symmetry up to about 9 ML. Considering the lattice mismatch and the atomic volume, we discuss these differences of structural change between Ni and Cu. Epitaxial growth of Ni on fcc-Au(001) is also reported.
    Download PDF (1239K)
  • Tomosuke Aono
    Subject area: Electron states in condensed matter.
    1997 Volume 66 Issue 3 Pages 664-675
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    A relaxation process is studied quantum mechanically in a quantum dot which is weakly coupled to two electrodes, using the real time path integration method. We consider the following situation: at first, the stationary current flows through the quantum dot which has a single energy level πv0. After a sudden change in the dot level to πv0, the electronic state starts to relax to another stationary state. We investigate the transient behaviors of the number of electrons in the dot and the current through the barriers. They oscillate with the frequencies (πv0 - μ ν ), where μ ν (μ = L, R) are the Fermi levels of two electrodes. The relative phase of these oscillation is determined by πv0 - \barπv0. The quantum effects decreases with time slower than the ordinary exponential decaying given by the master equation.
    Download PDF (799K)
  • Atsushi Ikawa
    Subject area: Electron states in condensed matter.
    1997 Volume 66 Issue 3 Pages 676-683
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The electronic and lattice structure of a pressure-quenched Se-Te mixed crystal was studied using a CNDO-type semi-empirical model.The fundamental structure without any superlattice modulation givesnine p bands. Three of these have large dispersions along the b axis and theothers have small dispersions in all directions. The former bands form six planar Fermi surfaces which nest with one another. This produces a stable 9× 2 superlattice structure with a glide reflection symmetry, in which wedge-like trimers are formed by shifts of theatoms. The superlattice structure can be regarded as a quasi-one-dimensionalsystem composed of 2/3, 5/9, and 7/9 filled chains along the b axis.
    Download PDF (551K)
  • Yoshinori Ohmasa, Makoto Yao, Hirohisa Endo
    Subject area: Electron states in condensed matter.
    1997 Volume 66 Issue 3 Pages 684-689
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    ESR spectra for the pressure-quenched monoclinic Te0.4Se0.6 are measured at the atmospheric pressure and low temperatures. The observed spectrum is composed of two different signals with large anisotropy, whose principal values of g-tensors are (gx, gy, gz)=(2.07, 1.90, 2.26) (A-component) and (gx, gy, gz)=(2.19, 1.89, 2.14) (B-component). It was found that the direction of the principal axes x and y are nearly parallel to the short and long bonds on the ac-plane, and z is parallel to b-axis. We discuss a possible model for the structure of these paramagnetic defect states.
    Download PDF (448K)
  • Takuhiro Ogawa, Yoshikazu Suzumura
    Subject area: Electron states in condensed matter.
    1997 Volume 66 Issue 3 Pages 690-702
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Electronic properties originated from the strong correlation have been examined for both metallic and insulating states in organic conductor, DCNQI-Cu salt by use of a periodic Anderson model with electron-phonon interaction. The local constraint imposed on the d-electron in the Cu atom is taken into account in terms of a method of the slave-boson. Compared with the previous mean-field calculation which corresponds to the global constraint, we have found novel aspects that the transition temperature is suppressed and that the magnetic susceptibility of the insulating state exhibits the temperature dependence of the Curie law. These results are in favor of the explanation of the experimental results.
    Download PDF (811K)
  • Masahide Kinoshita, Yukio Hirano, Makoto Kuwabara, Yoshiyuki Ono
    Subject area: Electronic transport in condensed matter.
    1997 Volume 66 Issue 3 Pages 703-711
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The effects of a site-type impurity potential and a bond-type disorder on the dynamical behaviors of charged and neutral solitons in polyacetylene are studied numerically. The charged soliton feels the site-type potential in the same way as an electron does, except for the broadening of the potential range due to the finite width of the soliton. While the neutral soliton goes through the site-type impurity potential as if there is nothing, reflecting the fact that the excess electron density vanishes everywhere in this case. On the other hand, there is no essential difference between the effects of the bond-type disorder on both solitons. The effective potential in this case looks like a step function, which can be explained in terms of matching or mismatching of the disorder with the dimerization pattern in the region outside of the soliton.
    Download PDF (859K)
  • Shiro Kawabata, Katsuhiro Nakamura
    Subject area: Electronic transport in condensed matter.
    1997 Volume 66 Issue 3 Pages 712-716
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    We investigate classical dynamics and quantum transport in weakly-opened square and Sinai billiards in the perpendicular magnetic field B. In the case of square billiard, the correlation field Bc of smoothed conductance varies irregularly with respect to B, while in the case of Sinai billiard it decreases monotonically with increase of B. By comparing between Bc and Lyapunov exponents in wide magnetic field regions, it follows that fluctuation features of Bc are attributed to the stability and instability of phase space in the underlying classical dynamics. In Sinai billiard case, geometry of the billiard yields Aharonov-Bohm oscillation in non-smoothed conductance, suppressing a symptom of chaos. Nevertheless, Bc evaluated in terms of the smoothed conductance nicely mimics the scaled variance of Lyapunov exponents.
    Download PDF (442K)
  • Wataru Izumida, Osamu Sakai, Yukihiro Shimizu
    Subject area: Electronic transport in condensed matter.
    1997 Volume 66 Issue 3 Pages 717-726
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Tunneling conductance of an Aharonov-Bohm circuit including two quantum dotsis calculatedbased on the general expression of the conductancein the linear response regime of the bias voltage.The calculation is performed in a wide temperature rangeby using numerical renormalization group method.Various types of AB oscillations appeardepending on the temperature and the potential depth of the dots.Especially, AB oscillations have strong higher harmonics components as a function of the magnetic flux when the potential of the dots is deep.This is related to the crossover of thespin state due to the Kondo effect on quantum dots.When the temperature rises up, the amplitude of the AB oscillations becomes smaller reflecting the breaking of the coherency.
    Download PDF (782K)
  • Tariq Hasan Gilani, Takehiko Ishiguro
    Subject area: Electronic transport in condensed matter.
    1997 Volume 66 Issue 3 Pages 727-737
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The transport and thermodynamical properties of highly conducting PF6-doped polypyrrole exhibiting resistivity maximum near 20 K are presented. The measurements were also carried out on elongated PF6-doped, nonmetallic PF6-doped and p-toluensulfonate-doped samples. The thermoelectric power, heat capacity and spin susceptibility all show a finite density of states at Fermi level. The Hall cofficient is found to be negative in all the samples, contradictory to the sign of thermoelectric power. The data including the magnetoresistance suggests the inhomogeneous structure of polypyrrole with metallic grain or domain separated by nonmetallic regions. The metallic conductance appearing below 20 K is explained by a percolation path model, but a logarithmic temperature dependence appearing below 0.5 K is remained unexplained.
    Download PDF (1120K)
  • Masamichi Sakai, Masanori Shinohara
    Subject area: Electronic structure and electrical properties of surfaces, interfaces and thin films.
    1997 Volume 66 Issue 3 Pages 738-748
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Influence of carrier scattering on the Franz-Keldysh (FK) effect in n-type GaAs has been studied by photoreflectance (PR). PR spectra obtained over a temperature range from 20 to 300, K have been analyzed in terms of the surface field, modulation field, and broadening energy, Γ, based on a one-electron FK theory taking into account the depth dependence of the built-in field and the non-flat band modulation effect. Temperature dependences of the surface and modulation fields thus obtained are explained by a temperature variation of the surface Fermi energy; the surface Fermi energy, pinned around mid gap, shifts towards the conduction band with decreasing temperature. At high temperatures above 200, K, Γ is accounted for by hole scattering due to intrinsic phonons, while conduction-electron scattering by a space-charge associated with an inhomogeneous distribution of a scatterer dominates Γ at temperature below 200, K.
    Download PDF (972K)
  • Tsuyoshi Yamaguchi
    Subject area: Electronic structure and electrical properties of surfaces, interfaces and thin films.
    1997 Volume 66 Issue 3 Pages 749-756
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Electronic states are calculated by the DV-Xα -LCAO method for two model clusters CuN8C32H16/Si157H116 and CuN8C32H16/Si145H132 of the copper phthalocyanine molecule (CuPc) adsorbed on the dimer row and the trough of the Si(001)2× 1 surface, respectively. About 3 electrons transfer from the Si substrate to CuPc. For CuPc on the dimer row, both occupied and unoccupied orbitals of the CuPc molecule have charge density all over the CuPc, but the charge density over the isoindoles on the dimer row is higher than that over others. Lower (higher) part of individual occupied (unoccupied) orbitals near the Fermi level has charge density around diagonal isoindoles parallel (perpendicular) to the dimer row. These and those for CuPc on the trough should be compared with the scanning tunneling microscopy images.
    Download PDF (652K)
  • Ming–Fa Lin, Der–San Chuu
    Subject area: Electronic structure and electrical properties of surfaces, interfaces and thin films.
    1997 Volume 66 Issue 3 Pages 757-764
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    A carbon nanotube exhibits the decoupled π plasmons of different angular momenta (L's).The magnetic flux is expected to be useful in identifying them. All the L-decoupled plasmons have strong dispersion relations with momentum (q).The L≠, 0 plasmons belong to optical plasmons, while the L=0plasmon could not exist at q→, 0.The former, respectively, behave as the plasmons in three- and two-dimensional electron gases at small and large q's.The plasmon frequencies would be affected by radius, chiral angle, and intertube interaction. To obtain the actual plasmon frequencies of a multi-shell nanotube, the intertube interactions from the neighboring shells have to be taken into account. The calculated results are consistent with the experimental measurements. A detailed comparison between a carbon nanotube and a graphite layer is also made. These two related systems may exhibit similar π plasmons, when L=0 in a nanotube. Furthermore, the chirality effect of the former corresponds to the anisotropy effect of the latter.The predicted q-, L-, and geometry-dependence of the π plasmonsneeds further experimental verifications.
    Download PDF (701K)
  • Masafumi Sera, Makoto Maki, Masahiko Hiroi, Norio Kobayashi
    Subject area: Superconductivity.
    1997 Volume 66 Issue 3 Pages 765-777
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    We have measured the thermal conductivity κ of La2-x-yRySrxCuO4 (R=Nd, Sm, Eu, Gd) and found that it shows the enhancement below the transition temperature Td2 from the LTO1 (low-temperature orthorhombic-1) to LTT (low-temperature tetragonal) (or LTO2 (low temperature orthorhombic-2)) phase and the magnitude of the enhancement strongly depends on x and y. We propose that the characteristic enhancement of κ below Td2 reflects the nature of the structure below Td2. From the results that in La1.875-yNdySr0.125CuO4, the LTT (or LTO2) phase appears at y>1/8, we propose the pair substitution of Sr2+ and Nd3+ ions where the loss of the strain energy is smaller and the local LTT (or LTO2) distortion is more largely enhanced than in the case of the independent substitution. We show that various characteristic properties associated with the LTT (or LTO2) transition could be explained naturally from the stand point that the local lattice distortion induced by the substituted ion plays an important role.
    Download PDF (1177K)
  • Yutaka Ueda, Naoki Fujiwara, Hiroshi Yasuoka
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 778-783
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    The magnetic and structural properties of (LixZn1-x)V2O4 at low temperatures have been studied. The ground state of metallic LiV2O4 is not any magnetically ordered one although the magnetic susceptibility shows the Curie-Weiss behavior above 100, K and a broad maximum around 20, K. With substituting Zn for Li the spin-glass state appears as the ground state in 0.1≤ x≤ 0.9. On the other hand the insulating ZnV2O4 exhibits the cubic to tetragonal transition at 50, K followed by the antiferromagnetic order below 40, K. ZnV2O4 shows a difference of magnetic susceptibility between zero-field and field cooled process below 95, K, which suggests the development of strong short-range correlation among spins. These transitions are sharply suppressed by the substitution of Li. The obtained results indicate that (LixZn1-x)V2O4 with the cubic spinel structure is a geometrically frustrated magnetic system.
    Download PDF (444K)
  • Junko Satooka, Atsuko Ito
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 784-792
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    We measured the temperature variations of magnetizations and Mössbauer spectrum of the diluted antiferromagnet Fe0.26Zn0.74F2. We have shown that the temperature variation of the Mössbauer spectrum is nicely explained in an aspect of dynamical behavior of the antiferromagnetic (AF) clusters. By combining the results of the magnetization and Mössbauer measurements, we have inferred that the spin-glass like freezing occurs at Tf=9.7, K not among individual spins but among the AF clusters. Therefore, we have concluded that Fe0.26Zn0.74F2 is a cluster-glass system and should be distinguished from an ordinary spin-glass system.
    Download PDF (788K)
  • Katsuaki Kodama, Hiroshi Harashina, Hisashi Sasaki, Yoshiaki Kobayashi ...
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 793-802
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Neutron inelastic scattering study has been performed on aligned single crystals of quasi-two-dimensional spin-gap system CaV4O9. By analyzing the dispersion curves and the structure factor of the triplet excitation, a physical picture of the present spin system has been constructed: The plaquette singlet units of four S=1/2 V-atoms within four “corner-linked” VO5 pyramids form the two-dimensional linkage of the spins by the interactions between the V-spins within the “edge-linked” VO5 pyramids. We have remeasured the NMR relaxation rates and obtained the spin-gap behavior consistent with the neutron results.
    Download PDF (682K)
  • Takeshi Emoto, Nobuyoshi Hosoito, Teruya Shinjo
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 803-808
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    119Sn Mössbauer measurements were performed for Fe/Au multilayers with 119Sn probes to study magnetic properties of Au layers. 119Sn Mössbauer probes were embedded in Au layers of Fe/Au multilayers which were made by ultra-high vacuum evaporation. 119Sn Mössbauer spectra showed large magnetic hyperfine fields, indicating that Au layers were polarized by ferromagnetic Fe layers. Mössbauer spectra were measured with applied field at 5, K. By computer fitting it was found that the hyperfine fields due to the magnetic polarization have both parallel and antiparallel contributions to the applied field direction.
    Download PDF (398K)
  • Kenji Nakajima, Yasuo Endoh, Syoichi Hosoya, Junichiro Wada, Detmar We ...
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 809-817
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    We have performed neutron scattering experiments on single crystals of La2NiO4+δ (δ =0.11, and 0.125) to study the effect of oxygen doping on the structural and magnetic properties. The degree of the excess oxygen order strongly influences the local crystal structure and interlayer magnetic correlation. The intralayer magnetic correlation is depressed by doping in the commensurate region (δ ≤ 0.11), then turns to increase in the incommensurate region (δ >0.11). Our experimental results are compared with existing results for oxygen and Sr doped La2NiO4.
    Download PDF (936K)
  • Haruhiro Hiraka, Yasuo Endoh, Kazuyoshi Yamada
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 818-826
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Inelastic neutron scattering experiments from a ferromagnetic metal of CoS2have been performed in a wide (q, ω) space and a wide temperature range across the Curie temperature, TC.Magnetic excitations in a small q region are well characterized to be spin-waves below TC.The sharp response of the spin-wave scattering suddenly broadensat q > 0.27Å-1 and ω > 8 meV.The paramagnetic fluctuations above TCare centered at ω=0 meV, which could be analyzed by a double Lorentzian form in q and ω.The line width Γ satisfies the dynamical scaling hypothesis;Γ=A0q2.5f(κ1/q).The dynamical feature in both below and above TC indicates that CoS2 is regarded as a typical itinerant ferromagnet.
    Download PDF (706K)
  • Yuuichi Tazuke, Tomohisa Takeyama
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 827-830
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Polycrystalline samples of MxTiSe2 with M=V, Cr, Mn, Fe, Co, Ni and Cu were prepared. All the compounds showed paramagnetic behavior at 4.2, K≤ T≤ 300, K. Effective paramagnetic moment μ eff of all the M-atoms are much smaller than ionic values, suggesting that the M-states are strongly hybridized with the TiSe2-band. Cr, Mn, Fe and Co may be in the high-spin states. The μ eff-data are compared with those of TyTiS2 with T=V, Mn, Fe, Co, Ni and Cu in our previous studies and with the band calculation results of Motizuki et al., and discussions are done about the electronic states of T- and M-atoms. It is suggested that the S-3p states are hardly hybridized and the Se-3p states are slightly hybridized with a Ti-3dε non-bonding band.
    Download PDF (338K)
  • Takashi Manago, Hideki Miyajima, Yoshichika Otani, Etsuo Akiba
    Subject area: Magnetic properties and materials.
    1997 Volume 66 Issue 3 Pages 831-838
    Published: March 01, 1997
    Released on J-STAGE: October 01, 1999
    JOURNAL RESTRICTED ACCESS
    Magnetic and structural properties of Ni fine particles (0.7± 0.2, μ m in diameter) coated with Pd (5, nm-- 37, nm in thickness) were investigated in a hydrogen atmosphere by means of magnetometry and X-ray diffractometry. The spontaneous magnetic moment is newly induced on the Pd atoms even at room temperature by the magnetic proximity effect between Ni core and Pd layer. Relatively large coercive force indicates the presence of the interface anisotropy. The magnetic polarization and the coercive force are suppressed by the hydrogenation. The temperature dependence of the magnetization shows a broad maximum around 80, K and an increase below 50, K. The maximum in magnetization is due to the enhanced paramagnetic contribution of Pd, and the gradual increase below 50, K is due to the Ni moment in contact with ferromagnetic Pd. A model for layered magnetic structure of the Ni particles coated with Pd is proposed.
    Download PDF (838K)
feedback
Top