Journal of the Physical Society of Japan
Online ISSN : 1347-4073
Print ISSN : 0031-9015
ISSN-L : 0031-9015
Volume 64, Issue 5
Displaying 1-48 of 48 articles from this issue
  • Norio Konno
    Subject area: Mathematical methods in physics.
    1995 Volume 64 Issue 5 Pages 1441-1444
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    Upper bounds on survival probabilities of discrete-time growth models are obtained by using a discrete-time version of the Harris lemma which is presented for the first time in this letter.
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  • Tadatsugu Hatori
    Subject area: Kinetic and transport theory of fluids; physical properties of gases.
    1995 Volume 64 Issue 5 Pages 1445-1448
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    In the chaotic process for the radial twist mapping with an arbitrary nonlinear rotation number function, it is shown that there exists a critical time Nc which separates two diffusion processes. In the short time limit N<< Nc, the diffusion coefficient is of the standard mapping value, in the opposite limit N>> Nc it is of the quasilinear value, and in the intermediate region N-- Nc the process is not appropriately described by diffusion.
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  • Eiji Kato, Tomohiro Murakami
    Subject area: Structure of liquids and solids; crystallography.
    1995 Volume 64 Issue 5 Pages 1449-1452
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    The dynamics of pressure-induced phase separation in N-isopropylacrylamide gels is investigated by the measurement of forward light scattering. A high hydrostatic pressure of 1030, atm which had been applied to the gel was suddenly decreased to atmospheric pressure at a constant temperature. Simultaneously, the time evolution of the intensity of forward-scattered light was measured. The scattered light constituted a speckle pattern, the intensity of which increased with time in accordance with the linearized theory of spinodal decomposition. In this experiment, the hydrostatic pressure acted as an external parameter which keeps the state of the gel in equilibrium in either a shruken phase or a swollen phase.
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  • Tadao Kasuya
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1453-1457
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    The experimental result of the de Haas van Alphen effectin CeAs is critically reexamined based on the magnetic polaron liquidand lattice model, to be consistent with other properties. It is shownthat, in contradiction to the claim that a large hole Fermi surface isnot observed, all the Fermi surfaces are observed satisfying theelectron-hole compensation, when the magnetic order, which is inducedthrough the magnetic polaron lattice, under applied magnetic field istaken into account. Other properties are also explainedconsistently. It is noted that the same situation exists for YbAs.
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  • Masashi Tokunaga, Noboru Miura, Hidenori Takagi, R. J. Cava
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1458-1461
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    We have observed de Haas-van Alphen (dHvA) oscillations inthe borocarbide superconductor, LuNi2B2C, under pulsed magneticfields up to 40, T. The observed oscillation frequency, 288± 7, T, corresponds to a cross section of 2.75× 10-2± 0.07×10-2, Å^{-2. The temperature dependence of the oscillationamplitude provides a cyclotron effective mass of m*ab=0.55±0.18me in the ab plane. By comparison with the results of bandstructure calculations, the oscillation can be assigned to a Lu 5dband which forms a small Fermi pocket near the Γpoint. These results support the validity of the band structurecalculation as a good starting point for understanding this class ofsuperconductors.
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  • Hiroshi Harashina, Katsuaki Kodama, Shin–ichi Shamoto, Masatoshi ...
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1462-1465
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    Superconductivity-induced phonon anomalies have beenstudied by inelastic neutron scattering for c-axis polarized modes ina single crystal of YBa2Cu3O7. A mode with B2u symmetry, which has out-of-phase motions of crystallographically distinct O(2)and O(3) atoms within a CuO2 plane, apparently exhibits a frequencydecrease and a narrowing of the profile width with onset of thesuperconductivity, while a mode which has in-phase motions of theseoxygens with respect to Cu atoms within the CuO2 plane does notshow an appreciable anomaly. The (x2-y2)-like symmetry of thesuperconducting order parameter is suggested by considering recenttheoretical arguments.
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  • Yasusi Koyama, Yositake Takane, Hiromichi Ebisawa
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1466-1470
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    We study mesoscopic fluctuations of the dc Josephsoneffect in a superconductor-dirty normal conductor-superconductorjunction using the Green function method. Our theoretical approach isvalid if the pair potential is considerably higher than the Thoulesscorrelation energy. The effects of temperature and sample geometry aretaken into account. The calculated result is in fairly good agreementwith that of the recent experiment by Takayanagi et al.
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  • Takao Nakama, Masato Hedo, Tsunehisa Maekawa, Miyuki Higa, Roland Rese ...
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1471-1475
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    Magnetoresistance, thermopower, Hall resistivity, acsusceptibility and magnetization have been measured for CeRu2 inthe normal and superconducting phases. In the normal state, there is amagnetic anomaly at 50, K, which is presumably due to development ofantiferromagnetic order. The H-T superconducting phase diagramobtained from ac susceptibility indicates the possibility of multiplesuperconducting phases.
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  • Shukichi Tanaka, Eiji Ueda, Masatoshi Sato, Kenji Tamasaku, Sin– ...
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1476-1480
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    The anisotropic nature of differential tunnelingconductance of high-Tc oxides has been studied by ScanningTunneling Microscopy/Spectroscopy (STM/STS) with the tip approachalong the [100] and [110] directions of single crystals ofYBa2Cu3O7 and La2-xSrxCuO4 (x=0.10 and0.15). Although the observed gap is larger in the [110] direction thanin the [100] direction, trial calculations of the k-dependenttunneling current which consider the shape of the electron wavefunctions of surface oxygens suggest that the data can be understoodon the basis of the (x2-y2)-like symmetry rather than thexy-like one. Zero-bias conductance peaks have been observed along the[100] direction.
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  • Akira Onodera, Norihiko Tamaki, Haruyasu Yamashita, Akihiro Terashita, ...
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1481-1483
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    An extraordinarily large dielectric anomaly was found inpotassium tellurite at 372, K. A D-E hysteresis loop was also observedat 210, K. This evidence indicates that K2TeO3 is a newferroelectric.
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  • Arisato Ejiri, Sinzou Kubota, Akira Hatano, Kazuhisa Yahagi
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1484-1488
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    Total photoelectric yield spectra of BaF2 and SrF2thin film crystals are relatively measured in the photon energy rangeof 10--35, eV with high resolution at room temperature. The yieldspectra obtained are investigated in comparison with availablereflection spectra in both materials and with an excitation spectrumof Auger free luminescence in BaF2. Evidence for a violation ofAuger free process is observed in BaF2. It is also revealed thatthe total width of the Ba2+5p core level is extraordinarily wide, 6, eV.
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  • A. K. Ghosh, Kalpana Sarkar
    Subject area: Mathematical methods in physics.
    1995 Volume 64 Issue 5 Pages 1489-1500
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    This paper deals with the problem of unsteady motion of an incompressible electrically conducting dusty fluid in a channel bounded by two rigid, non-conducting, infinite parallel plates subject to the conditions that an external magnetic field is acting transversely to the plates and the flow is generated from rest due to velocity tooth pulses applied on the upper plate with the lower plate held fixed. It is assumed that no external electric field is imposed on the fluid-particle system and the magnetic Reynolds number is very small. the problem is solved by the method of Fourier Analysis instead of applying the method of Laplace transforms which involves complicated inversions. The exact expressions for the velocities of the fluid and of the dust particles and the skin-friction at the walls are obtained. The results are analyzed quantitatively with a view to find the effects of the magnetic field and the dust particles on the flow as well as on the wall shear stresses. Finally, the exact solution of the problem is obtained by the method of Laplace transforms and this result has been compared with that of the present one. It is found that both the methods provide the same exact solution although the method of Fourier analysis is much simpler than the method of Laplace transforms.
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  • Kazuaki Nakayama, Miki Wadati
    Subject area: Mathematical methods in physics.
    1995 Volume 64 Issue 5 Pages 1501-1505
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    Time evolution for hypersurfaces in a curved space ispresented. A reaction-diffusion equation is also considered in acurved space and an extension of the eikonal equation isobtained. Further, randomness of the space is considered. The“random eikonal equation” is derived and is shown to beequivalent to the Karder-Parisi-Zhang (KPZ) equation.
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  • Kyoichi Tsurusaki, Tetsuo Deguchi
    Subject area: Mathematical methods in physics.
    1995 Volume 64 Issue 5 Pages 1506-1518
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    Fractions of knotted polygons in Gaussian random polygonare numerically studied. Three dimensional random polygons with N stepsare prepared by closed N-step Gaussian random walks. LetPK(N) denote the probability that an N-step Gaussian polygon has aknot type K. For prime knots (31, 41, 51, 52) andcomposite knots (31 #31, 31 #41, 31 #31 #31), PK(N)'s are evaluated in the range 30≤ N≤ 2400. We confirm thata scaling formula gives nice fitting curves for the numerical dataplots of PK(N) versus N for the different knot types.
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  • Saburo Kakei, Narimasa Sasa, Junkichi Satsuma
    Subject area: Mathematical methods in physics.
    1995 Volume 64 Issue 5 Pages 1519-1523
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    A generalized derivative nonlinear Schrödingerequation, iqt+qxx+2iγ | q| 2qx+2i(γ -1)q2qx*+(γ -1)(γ -2)| q| 4q=0, isstudied by means of Hirota's bilinear formalism. Soliton solutions areconstructed as quotients of Wronski-type determinants. A relationshipbetween the bilinear structure and gauge transformation is alsodiscussed.
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  • Kwok W. Chow
    Subject area: Mathematical methods in physics.
    1995 Volume 64 Issue 5 Pages 1524-1528
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    A class of exact solutions of some nonlinear envelopeequations is derived by the Hirota bilinear method. These solutionsreduce to a plane wave in the far field but generally are not darksolitons. In one asymptotic regime they simplify to solitary waves ona continuous wave background.
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  • Naomichi Hatano
    Subject area: Mathematical methods in physics.
    1995 Volume 64 Issue 5 Pages 1529-1551
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    Superfluid-insulator transitions are studied for theground state of the Boson Hubbard model with random potentials. Thetopology of the phase diagram is discussed. Reentrant transitionsbetween the superfluid phase and the Bose-glass insulator phase arefound in an arbitrary number of dimensions. The present results arebased on a perturbational scaling argument and a quantum Monte Carlocalculation. The Monte Carlo algorithm is also reported in detail.
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  • Miki Wadati
    Subject area: Mathematical methods in physics.
    1995 Volume 64 Issue 5 Pages 1552-1556
    Published: May 01, 1995
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    The thermal Bethe ansatz is formulated for one-dimensionalintegrable boson systems. From the bosonic formulation, fractionalstatistics is derived in simple manner. The key is a choice of thephase shift or the derivative of the phase shift. The ideal g-on gasis defined based on the thermal Bethe ansatz. The discussion alsoapplies for one-dimensional integrable fermion systems.
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  • Chien–Cheng Chang, Chin–Chou Chu, Cheng–Chien Liu, C ...
    Subject area: Electricity and magnetism: fields and charged particles.
    1995 Volume 64 Issue 5 Pages 1557-1578
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    A combined numerical and experimental analysis has beencarried out for investigating the behavior of a pair of line vortices, mutually propelled to approach a circular cylinder. The flow isassumed to be two-dimensional in numerical simulations, and whichcondition is examined carefully in laboratory experiments. TheReynolds number Re=κ /ν based on the initial circulation κ of the vortices and the kinematic viscosity ν of the fluid rangesfrom 100 to 1500. Flow behaviors are identified and classified intothree patterns with six types of characteristic trajectoriesassociated with the primary and secondary vortices. Of particularinterest are the phenomena of rebound and reversal, exhibitedrespectively by the primary vortices moving against the cylinder underdifferent flow conditions. Stable pairs of line vortices are generatedin laboratory experiments; flow visualization shows excellentagreement with numerical results in the comparisons of several flowbehaviors.
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  • Hiromi Unoki
    Subject area: Structure of liquids and solids; crystallography.
    1995 Volume 64 Issue 5 Pages 1579-1589
    Published: May 01, 1995
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    The relation between the temperature dependence of thespectroscopically-observable phonon-frequency square, ω 2Oof the optical mode or ω 2A of the acoustic mode, and thatof relevant thermodynamic coefficients is considered. A specialemphasis is laid on the piezoelectric or sublattice-piezoelectricinteraction between optical and acoustic modes in the lattice wherenot all the constituent atoms occupy the center of symmetry. Thetemperature dependence of the bilinearly-coupled-mode frequency isfound to deviate from that of the renormalized thermodynamicparameters observed experimentally, which results in some modificationof the Lyddane-Sachs-Teller relation. The mixing of interactingphonons, their normal modes and possible strain-induced ionic-sitedisplacements are also discussed.
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  • Teruhiko Mabuchi, Tatsuya Sasaki, Yasusi Ojiro
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1590-1594
    Published: May 01, 1995
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    Low-energy electron energy loss spectra of transitionmetal halides MnBr2, MnF2 and FeF3 are measured for primaryenergies 20 to 400, V. For Mn halides, there are loss peaks which arethought to be due to the forbidden d-d transitions in Mn++ions. The intensities of these loss peaks are primary energy dependentand decrease with the increase of the incident energy. As to FeF3, intensities of loss peaks are also incident energy dependent, but thedependence is different among each loss peak. As to the origin of theprimary energy dependent losses, it is thought that the mixing ofligand halide p-orbitals with the d-orbitals of central metal ions isessential.
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  • Yoshiaki Ono, Tamifusa Matsuura, Yoshihiro Kuroda
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1595-1615
    Published: May 01, 1995
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    We investigate finite temperature properties of theUd-infinite d-p model in the auxiliary boson representation withinthe leading order approximation in the 1/N-expansion. We obtain aunified description of the system valid over the whole temperaturerange divided by the two characteristic energies, the binding eppnergyof the resonance state of the auxiliary boson, ω0, and thecoherence temperature, T0, of O(ω0/10). At T<< T0, anew coherent band (in-gap band) appears inside the charge-transfer gapupon carrier doping and behaves as Fermi liquid with large Fermisurface determined by the Luttinger sum rule. The band width is anincreasing function of carrier doping rate and of O(ω 0). AtT>ω0, the chemical potential is below the in-gap band and thedoped holes are mostly on the O-2p band forming small Fermi surface, while the Cu-3d holes behave like spin-½localized moments. At T0\preceq T\preceq ω 0, crossover phenomena betweenthe two limiting cases are observed. The in-gap band becomesquasi-coherent and the inverse life-time due to the incoherentscattering increases linearly with T. The observed crossover phenomenashow significant contrast to the distinct phase transition obtained inthe mean field theory.
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  • Tomozo Tomoyose
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1616-1621
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    The transverse effective charge ZT of ANB 8-Ncompounds is expressed as a function of the Phillips ionicity. Thechemical trend of ZT for zincblende ANB 8-N compounds iscalculated on the basis of a lattice-distortion model where atoms areassumed to be slightly displaced. The calculated ZT is comparedwith the experimental ZT for III-V, II-VI, and I-VII compounds. Itis found that the theoretical ZT well reproduces the observedchemical trend of ZT for these compounds.
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  • Nobuo Narita, Sumiaki Nagai, Shigeru Saito, Kenji Nakao
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1622-1628
    Published: May 01, 1995
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    The electronic band structure of layered semiconductorα -In2Se3 is investigated by using the self-consistentnumerical-basis-set LCAO method with a potential based on the localdensity approximation.The resulting energy band gap occurs betweenΓ5- and Γ1+ and its value is0.99, eV. The effective masses in conduction and valence are 0.13m0and 3.2m0, respectively. The self-consistent valence of each ion isas follows: In0.95+In1.23+Se1.52-Se0.54-Se0.12-. Thusthe compound has a considerably ionic character though the interlayerbonding is found to be partly covalent from the valence electroncharge distribution.
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  • Masayoshi Mikami, Takeo Fujiwara
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1629-1643
    Published: May 01, 1995
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    Transferability of the first-principle pseudopotentials istested for a pseudoatom embedded in a jellium. The Hamann'spseudopotential (Phys. Rev. B40 (1989) 2980) and its separable formare analyzed in this transferability test. Elements examined in thispaper are classified into two; the first class is elements in whicheven pseudopotential without core-correction can assure sufficienttransferability, e.g. Al, Si; the second one is elements in which onlypsedopotential with core-correction can assure sufficienttransferability, e.g. alkali metal elements. The neutral sphere radiusis the most important parameter for the transferability which issensibly dependent upon the charge density parameter rs of thejellium. Once the neutral sphere radius is smaller than the coreradius of the pseudopotential, sufficient transferability cannotrevive even with the core-correction in a pseudoatom-in-jellium model.
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  • Satoshi Taniguchi, Takashi Nishikawa, Yukio Yasui, Yoshiaki Kobayashi, ...
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1644-1650
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    The metal-insulator transition of La3Ni2O7-δ with 2-dimensional electrons has been studied. Various physicalproperties can be understood by introducing a model of chargeorderings in the NiO2 planes induced by oxygen orderings. Argumentson the non-occurrence of the superconductivity are also given.
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  • C. D. Hu
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1651-1657
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    We used the Bloch theory to study single-electrontunneling. It was found that calculation can be performed easily inthe crystal momentum representation. We showed analytically that underac-biased voltage or microwave radiation the system produces responsewith subharmonic structures analogous to those of Josephson tunneling. Our method treated the “interband transition” as smallperturbation and thus fits most experimental conditions. Somenumerical results were also given.
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  • Takeshi Inaoka
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1658-1672
    Published: May 01, 1995
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    We investigate the ground-state electronic structure ofsmall spherical metal shells on the basis of a model system whichconsists of valence electrons and a spherical jellium shell (JS). Theelectron density distribution and the effective one-particle potentialare calculated by using the local-density-functional formalisminvolving the self-interaction correction (SIC). By varying theelectron number and the inner radius of the JS, conserving the chargeneutrality of the whole system, we closely examine how the electronicstructure evolves from a jellium-sphere system to an electron systemsharply localized around a spherical surface. By comparing the resultsin the SIC scheme with those in the ordinary Kohn-Sham scheme, weexplore effects of the SIC especially on energy levels of occupiedelectron shells and on the total energy.
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  • Tetsuo Okane, Mitsuki Yamada, Shoji Suzuki, Shigeru Sato, Toyohiko Kin ...
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1673-1682
    Published: May 01, 1995
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    We have studied the electronic structures of Ce/Ni(110)system by the 4d-4f resonant photoemission using synchrotron radiationand the Ce3d core level X-ray photoemission. The results areinterpreted in conjunction with the inter-diffusion of Ce and Ni atomsthrough the interface. The annealing after the deposition of Ce causesactive diffusion of Ce atoms into the Ni substrate and Ni atoms intothe Ce layers and brings about a well-ordered surface. Both the Ce3dcore level and valence band spectra show remarkable changes dependingon the degree of inter-diffusion between Ce and Ni at theinterface. It is revealed that a close relation exists between the Ceconcentration and strength of the 4f-conduction states hybridizationin the surface layer. The importance of the Ce4f-Ni3d hybridization isemphasized.
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  • Ryusuke Ikeda
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1683-1702
    Published: May 01, 1995
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    A picture for vortex liquid regime in strongly type IIsuperconductors is presented on the basis of the GL fluctuation theorydeveloped in terms of the Landau level representation of the orderparameter. It is emphasized that the critical mode, driving themelting transition and determining the phase coherence of the system, plays essential roles to low energy properties in the vortex liquidregime of extremely clean systems. Consequently, a correlation betweenthermodynamic and transport properties is predicted. Further, thepresence of two different types of field variations, making fielddependences of phenomena complicated, is pointed out, and theireffects on the melting line of the vortex lattice and on physicalquantities are discussed. In particular, the present theory predictsthat the London-like field dependence of the melting temperature isnot incompatible with the scaling behavior based on the lowest Landaumode in the vortex liquid regime, and that the melting in 90, K YBCOis always 3D-like at finite temperatures. Crucial differences betweenthe present GL framework and models based on the London limit for thevortex liquid regime are emphasized through a calculation of tiltmodulus in the liquid regime and some consideration on the linearresponse in the force free configuration.
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  • Masashige Matsumoto, Hiroyuki Shiba
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1703-1713
    Published: May 01, 1995
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    The boundary effect in d-wave superconductors is studiedfor specular and rough surfaces. In particular, the local density ofstates near the boundary is examined to see how the d-wave symmetryshows up in the direction dependence of the surface relative to theorder parameter.
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  • Yasushi Nagato, Katsuhiko Nagai
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1714-1725
    Published: May 01, 1995
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    We study the density of states of the normal layer in theS--N--S proximity-contact systems in the clean limit, taking accountof the finite reflection at the interface as well as a possiblepairing interaction in the normal layer. The self--consistent pairpotential and the density of states are calculated. It is found thatwhen the normal layer has a repulsive pairing interaction, there occuradditional states in the low energy range.
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  • Yoshiaki Tanaka
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1726-1747
    Published: May 01, 1995
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    For the Ising model on the two-dimensional lattice withM× N spin sites (M is a finite number; N→ ∞), arbitrary two-spin correlations are evaluated exactly. We make use ofspinor analysis, which was employed by Kaufman and Onsager. Thezero-field magnetic susceptibility χ0 that is equal to the sumof all two-spin correlations, is calculated.
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  • Yutaka Nakai, Yorihiko Tsunoda
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1748-1753
    Published: May 01, 1995
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    A neutron diffraction experiment for a powder specimenwith 0.19, at\permil Sn, revealed that the magenetic moment at site 2 approaches zero near 100, K, while the moment at site I reaches themaximum near 100, K and nears zero at about 140 or 150, K. Themagnitudes of the vector sum of the magnetic moments on theneighboring sites for the four crystallographically inequivavent siteswere calculated as functions of temperature. These magnitudes explainprevious results of the temperature variation of hyperfine magneticfields in 119Sn of α-Mn(Sn). However, they cannot explain thetemperature variation of the magnetic moments, if the magnitude ofeach magnetic moment is assumed to be determined by the molecularfield.
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  • Shin"ichi Ishimaru, Koh–ichi Suzuki, Ryuichi Ikeda
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1754-1758
    Published: May 01, 1995
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    The temperature dependence of the 1H NMR spin-latticerelaxation time (T1) and 2H spectra were measured in(CH3NH3)5Bi2Cl11 and (CH3ND3)5Bi2Cl11 toinvestigate dynamic nature of the paraelectric-ferroelectric phasetransition. T1 anomaly was observed in the close vicinity of thetransition temperature of 306.5, K and attributed to criticalfluctuation associated with the phase transition. The precessionalmotion of the methylammonium cation derived from the observed 2Hspectra seems to be concerned with the order-disorder transitionexpected from the X-ray study.
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  • Hitoshi Ohta, Masato Sumikawa, Mitsuhiro Motokawa, Sumiko Noro, Tokio ...
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1759-1765
    Published: May 01, 1995
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    Antiferromagnetic resonances (AFMR) of Ba2Cu3O4Cl2 havebeen studied by submillimeter wave ESR in the frequency region from 90to 383, GHz using the pulsed magnetic field up to 16, T. The AFMR'sobserved at 1.8, K clearly showed an easy plane type anisotropy. Thetemperature dependence of AFMR has been observed from 1.8, K to 265, Kand it will be discussed in connection with the characteristicmagnetic feature of Ba2Cu3O4Cl2. The result of themagnetization measurement is also discussed.
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  • Atsuko Ito, Keiko Iwai, Hiroaki Kato
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1766-1774
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    The diluted antiferromagnet Fe0.2Mg0.8TiO3 hasbeen investigated. The temperature variation of magnetization exhibitsthe spin-glass (SG)-like behavior, and the SG-freezing temperatureTSG is estimated to be 6, K. On the other hand, theMössbauer studies have demonstrated that the magneticallybroadened spectrum appears superimposing upon the paramagnetic doubletalready at -- 14, K, and as the temperature decreases the magneticspectrum increases in relative intensity accompanying the decrease ofthe line width. In order to analyze the Mössbauer spectra fromthe dynamical aspect, we applied the stochastic treatment ofrelaxation phenomena formulated by Blume. Combining the results of themagnetization and Mössbauer measurements, it has been concludedthat the SG-freezing in Fe0.2Mg0.8TiO3 occurs among the“AF clusters” but not among individual spins.
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  • Keiichi Moriya, Kozo Iwauchi, Masayuki Ushida, Atsushi Nakagawa, Kazun ...
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1775-1784
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    The dielectric constant of Pb2xSn2(1-x)P2S6single crystals was measured at several frequencies from 0.1 to100, kHz between 3.7 and 420, K. No phase transition is observed atx=1.0. The ferroelectric-paraelectric phase transition temperaturedecreases linearly as x increases, but curves slightly around x=0.3and bends at x=0.61. The lowering of the phase transition with anincrease in x is considered to be a result of the motion of theSn2+ ion. At x=0.61 and 0.66, the relatively large dispersions wereinterpreted as diffuse phase transitions caused by the fluctuation ofthe concentration of Pb2+ ions.
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  • Shun"i Kawase
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1785-1791
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    The Rayleigh and Brillouin scattering experiments havebeen carried out for the systems of benzene-primary alcoholsCnH2n+1OH (n=1 to 5) and benzene-ethyl ether in order to makesure the applicability to the arguments on the thermodynamicquantities based on the density and concentration fluctuationsproposed by Bhatia and Thornton. The effect of the difference in themolar volumes of the constituents is, in particular, emphasized forthe obtained concentration-concentration fluctuation in the longwavelength limit, Scc(0, , c, , T). A new method is also proposed toderive the Gibbs free energy of mixing ΔG, by using thedata of Scc(0, , c, , T). The obtained ΔG forbenzene-ethyl ether is nearly equal to RT(cln c+(1-c)ln (1-c)) and thosefor benzene-pentanol, butanol and propanol are, more or less, similarto those of typical binary fluids. While, ΔG's ofbenzene-methanol and ethanol in their magnitudes show phase separationtendencies, which are also seen in the shapes of Scc(0, , c, , T)'s.
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  • Satoshi Hohnoki, Akira Hasegawa
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1792-1799
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    Absorption spectra which originate from directvalence-band-to-conduction-band transitions in strained-layersuperlattices (SLSs) are studied theoretically. The electronicstructures are calculated by using the Luttinger-Kohn Hamiltonian inthe Kronig-Penney model. The absorption coefficients are evaluated bytaking the mixing of heavy- and light-hole states into account. As aresult of calculation, firstly, origins of fine structures in theabsorption spectra observed at a room temperature for type IZnSe(22, Å)--ZnS(23, Å) SLS are clarifiedsatisfactorily. Secondly, novel properties of type II ZnTe--ZnSe arepredicted, i.e. it is revealed that the absorption intensity is oneorder of magnitude less in type II SLS than in type I SLS, and that intype II SLS the strength for any transitions to the higher conductionand from the higher valence subbands is greatly enhanced, in sharpcontrast to the type I SLS.
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  • Yukio Tagawa, Naoshi Suzuki
    Subject area: Electron states in condensed matter.
    1995 Volume 64 Issue 5 Pages 1800-1809
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    Effects of the electron correlation on the opticalabsorption due to inter-band transition (CT absorption) and due tonon-linear excitations (mid-gap absorption) in one-dimensionalPeierls-Hubbard CDW systems are studied by using the exactdiagonalization method. The correlation effect of on-site repulsion Uis fairly small for both the CT and the mid-gap absorption except inthe boundary region between the CDW and AF phases while thecorrelation effect of inter-site repulsion V is significant for boththe transitions. With increasing V the CT transition is suppressed andthe exciton transition grows. As to the mid-gap absorption theintensities of absorption associated with the transitions from (or to)a defect state of the non-linear excitations to (or from) aconduction- or valence-band state are enhanced strongly by the effectof V. The absorption spectrum in the AF state is also calculated. Onlythe lowest optically-allowed state has a large oscillator strength andhence the absorption spectrum in the AF state is very sharp comparedwith the CT transition in the CDW state.
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  • Tetsuo Kaneko
    Subject area: Materials science.
    1995 Volume 64 Issue 5 Pages 1810-1822
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    The behavior of adhesive charged macroparticles wasinvestigated on the basis of analytical solutions obtained using themean spherical approximation. When ionic species regarded as pointcharges are added to a dispersed system of the macroparticles, thissystem, if they are sufficiently highly charged and the system issufficiently dense, readily undergoes phase separation. However, whenthe macroparticles are not highly charged or the system is notsufficiently dense, it is difficult to observe this phenomenon eventhough a large quantity of the ionic species is added to the dispersedsystem. For this behavior, the contribution of the nonlinearcondensation of the ionic species is considered.
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  • ken–ichi Oshio, Hideo Yahata
    Subject area: Physical chemistry.
    1995 Volume 64 Issue 5 Pages 1823-1836
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    A simulation model of the Gunn-effect device isconsidered. Using the finite difference method, spatio-temporalevolution of the system in the presence of the impact-ionizationeffect in the device is computed for n-GaAs with the recombinationrate and the bias voltage being taken as the control parameters. Wethereby show the motion of the Gunn-effect device exhibitsnon-periodic behavior due to its own autonomous nonlinearity even ifit is not driven by an external periodic field. The domain motion isperturbed by the carrier generation due to the impact ionization, andit becomes non-periodic for specially chosen model parameters. It alsoexhibits the interpulse incoherent current oscillations similar to theones observed experimentally. Some remarks are given on the mechanismgiving rise to the nonperiodicity on the basis of spatio-temporalevolution of the high-field domain.
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  • Tetsuya Matsuno, Masahiro Iguchi, Kiyoshi Toko, Kaoru Yamafuji
    Subject area: Materials science.
    1995 Volume 64 Issue 5 Pages 1837-1850
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    It is clarified that the coupled oscillator system, whichhas the output of the phase coherency, can learn mapping fromspecified phase patterns to specified phase coherencies. The systemconsidered here has the output unit which is a group of oscillatorscoupled both to the other oscillators of the system and also to themean field generated by the output unit itself. It is analytically andnumerically shown that the system can learn the above specifiedmapping. The effect of the distribution of the natural frequency ofoscillators on the dynamics of the system is also investigated. It isshown that the system exhibits oscillatory and complex (chaotic)output when the phase pattern sufficiently different from the learnedpatterns is input into the system.
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  • Onkar Prasad, Poonam Tandon, V. D. Gupta, Shantanu Rastogi
    Subject area: Materials science.
    1995 Volume 64 Issue 5 Pages 1851-1857
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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    The present work is a study of phonons and theirdispersion in Poly (α-aminoisobutyric acid), which is an exampleof a polyamino acid having 310 helical conformation. It has beenused as a model to carry out conformational studies on proteins andpolypeptides. Dispersion curves show two interesting oppositefeatures: (a) tendency of some curves to crowd or close-in near δ =ψ, which is indicative of coupling between various modes and (b)repulsion between dispersion curves belonging to same symmetryspecies. Specific heat is obtained from dispersion curves viadensity-of-states.
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  • Shin Takeuchi
    Subject area: Mechanical and acoustical properties of condesed matter.
    1995 Volume 64 Issue 5 Pages 1858-1859
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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  • Yasushi Amako, Syunjiro Saoka, Hiroshi Yoshie, Hiroyuki Nagai, Kengo A ...
    Subject area: Magnetic properties and materials.
    1995 Volume 64 Issue 5 Pages 1860-1861
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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  • Roger Moret, Pascale Launois, Sylvain Ravy
    Subject area: Structure of liquids and solids; crystallography.
    1995 Volume 64 Issue 5 Pages 1862
    Published: May 01, 1995
    Released on J-STAGE: October 01, 1999
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