Journal of the Physical Society of Japan
Online ISSN : 1347-4073
Print ISSN : 0031-9015
ISSN-L : 0031-9015
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Volume 57, Issue 9
Displaying 1-50 of 55 articles from this issue
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  • Out-of-Plane Measurement of the 65Cu(e, e′p0) Reaction in the Giant Resonance Region
    Yoshiyuki Kawazoe, Haruhisa Miyase, Hiroaki Tsubota, Katsumasa Namai, ...
    1988 Volume 57 Issue 9 Pages 2869-2872
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2869
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    The 65Cu(e, e′p0) coincidence cross section at θe′=30° and φp=−90° is measured at θp=0°−180° in the giant dipole resonance energy region. The present geometrical setup is selected to enhance the Coulomb multipole strength. The angular distribution obtained is decomposed into a Legendre series and analyzed by the theory of Kleppinger and Walecka. The result shows the success in geometrically obtaining the contribution of electric quadrupole excitation.
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  • Neutrino Mass and End-Point Energy of 3H β-Decay
    Hirokane Kawakami, Sadayuki Kato, Fujio Naito, Keigo Nisimura, Takayos ...
    1988 Volume 57 Issue 9 Pages 2873-2876
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2873
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    The end-point energy of 3H β-decay is re-examined and found as E0=18582.5±4.1 eV by a new measurement of the electron energy spectrum at INS. Also, an upper limit of the electron anti-neutrino mass is obtained as mν<29 eV by combining with the result of a previous experiment.
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  • Conservation of Angular Momentum in the Direct Simulation Monte Carlo Method
    Kenichi Nanbu, Yasuo Watanabe, Saburo Igarashi
    1988 Volume 57 Issue 9 Pages 2877-2880
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2877
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    Meiburg presented the view that the direct simulation Monte Carlo (DSMC) method might not be usable for the computation of vortical flows because the angular momentum is not conserved in collision [Phys. Fluids, 29 (1986) 3107]. In this Letter, that view is clarified. It is first shown that the vorticity is irrelevant to the angular momentum conservation, i.e., it is related to the total linear momentum of molecules in a cell. Since the linear momentum conservation is satisfied in the DSMC method, it is positive that the method is usable in computing vortical flows. Next, it is shown that the expectation of the total angular momentum of molecules in a cell is conserved in the DSMC method; the variance of it is proportional to the square of the cell dimension, so that the smaller the cell, the more accurately the angular momentum conservation is satisfied.
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  • Stability of m=1 Mode in the Presence of m=0 Perturbation in Reversed Field Pinch
    Ken-ichi Hattori
    1988 Volume 57 Issue 9 Pages 2881-2884
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2881
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    Stability of the m=1 mode is examined in the presence of external m=0 perturbations, i.e., toroidal field ripple arising from the discreteness of toroidal coils. Response of the plasma is taken into account self-consistently using the Bessel Function Model. The Δ′ criterion and energy principle are applied to the system and the stability of the m=1 resistive and ideal modes is shown to be improved by reducing the toroidal ripple.
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  • Observation of Acoustic de Haas-van Alphen Effect in Heavy Electron Compound CeB6
    Terutaka Goto, Takashi Suzuki, Yohichi Ohe, Shinichi Sakatsume, Satoru ...
    1988 Volume 57 Issue 9 Pages 2885-2888
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2885
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    The de Haas-van Alphen oscillations of the sound velocity in the Kondo lattice compound CeB6 have been observed at low temperatures down to 27 mK. The obtained cyclotron effective masses of 3.1∼29.8 mO in CeB6 indicate a mass enhancement about 100 times larger than that of the counterpart ρ branch in the reference compound LaB6.
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  • Stochastic Aspects of the Sliding Charge-Density-Wave Current Spectra
    Takashi Miyashita, Hajime Takayama
    1988 Volume 57 Issue 9 Pages 2889-2892
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2889
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    It is shown that the simulation on the charge density wave (CDW) dynamics described by the 1D Fukuyama-Lee-Rice model with heat bath effects reproduces qualitatively many stochastic aspects of the CDW current spectra, such as the temporal fluctuation of the narrow band noise spectrum observed in recent experiments. The results are interpreted as the consequences of the CDW glassy dynamics above the threshold field, i.e., the activated random process between quasi-stationary configurations of the sliding CDW.
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  • Anomalous Nuclear Relaxation and Knight Shift Behaviors of 205Tl in High-Tc Tl2Ba2Ca1Cu2O8+δ
    Kenji Fujiwara, Yoshio Kitaoka, Kunisuke Asayama, Hiroshi Katayama-Yos ...
    1988 Volume 57 Issue 9 Pages 2893-2896
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2893
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    The nuclear relaxation rate, 1⁄T1, and Knight shift have been investigated between 4.2 K and 300 K by 205Tl nuclear magnetic resonance (NMR) for Tl2Ba2Ca1Cu2O8+δ with Tc=100 K. It has been observed that there are two Tl sites possessing a different electronic state. The distinct decrease of 1⁄T1 and Knight shift for both Tl sites has been found just below an onset temperature of T0=115 K rather than a zero-resistance temperature of Tc=100 K. Above T0, 1⁄T1 is not of the Korringa-type with T1T=const., but exhibits weak temperature dependence, resembling the behavior of the CuO2 plane site of YBa2Cu3O7. The 1⁄T1 for Tl sites possessing no magnetic moments is demonstrated to reflect the strong spin correlation above T0 through the hybridization with the Cu d-wave function.
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  • NMR and NQR Studies of 17O and 63Cu in CuO2 Plane of High-Tc YBa2Cu3O6.65 with Tc=61 K
    Kenji Ishida, Yoshio Kitaoka, Kunisuke Asayama, Hiroshi Katayama-Yoshi ...
    1988 Volume 57 Issue 9 Pages 2897-2900
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2897
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    The microscopic property of each oxygen and copper site in the CuO2 plane of YBa2Cu3O6.65 with Tc=61 K has been investigated by 17O NMR and 63Cu NQR techniques. It has been found that the nuclear spin-lattice relaxation rate 1⁄T1 for Cu sites is depressed by three orders of magnitude as compared with that for YBa2Cu3O7 with Tc=92 K, whereas 1⁄T1 for oxygen sites exhibits a rather small change, decreasing approximately to one-fourth (1/4). From this difference of the relaxation behavior between oxygen and Cu sites, it is derived that the progressive reduction of 1⁄T1 for oxygen sites is responsible for the decrease of the p-hole carriers, while the extraordinary decrease of 1⁄T1 for Cu sites is due to the dramatic suppression of the low-frequency components of an antiferromagnetic spin fluctuation of nearly localized d electrons. The spin fluctuation at the Cu sites is found to strongly correlate with the p-hole content.
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  • Magnetic Mechanism of Superconductivity in Coupled Spin-Fermion Systems
    Masatoshi Imada, Naoto Nagaosa, Yasuhiro Hatsugai
    1988 Volume 57 Issue 9 Pages 2901-2904
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2901
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    A coupled spin-fermion model is presented as a two-band model of high-Tc superconductivity. The experimental relevance of the model is discussed. The high-Tc superconductivity is discussed the continuity of the strong coupling superconductivity to the weak coupling region. The attractive interaction of holes seems to exist over a wide range of parameters from weak to strong coupling cases. The small transfer region is useful to understand the pairing mechanism in the relevant strong coupling region. The model includes the effective Hamiltonian of the single-band Hubbard model as a special case.
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  • NQR Study of Copper in YBa2(Cu1−xZnx)3O7−y
    Yoh Kohori, Hirofumi Shibai, Yasukage Oda, Yoshio Kitaoka, Takao Kohar ...
    1988 Volume 57 Issue 9 Pages 2905-2907
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2905
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    An NQR study of copper in YBa2Cu3O7−y with the doping of Zn impurity has been performed. The nuclear spin lattice relaxation time, T1, of 63Cu was measured. The 1⁄T1 of Cu in the CuO2 plane follows the Korringa law in the normal state below 90 K, and is saturated above 100 K. From this result, it is expected that T1 in the normal state of YBa2Cu3O7−y follows the Korringa law below 90 K.
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  • Observation of Nuclear Resonance of Cu in Antiferromagnetic La2CuO4−δ and CuO
    Toshinobu Tsuda, Tadashi Shimizu, Hiroshi Yasuoka, Kohji Kishio, Koich ...
    1988 Volume 57 Issue 9 Pages 2908-2911
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2908
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    The zero-field nuclear magnetic resonance (NMR) of Cu in the high-Tc related oxide, La2CuO4−δ, has been observed at 93.85±0.1 MHz for 63Cu and 100.1±0.1 MHz for 65Cu with well-articulated quadrupole splittings at 1.3 K. The resonance pattern is successfully analyzed as a result of the combined effect of a quadrupole coupling (coupling constant νQ=31.9 MHz for 63Cu and 29.5 MHz for 65Cu with asymmetry parameter η=0.03) and a Zeeman term where the internal field (HN=78.78 kOe) is nearly perpendicular to the direction of the maximum electric field gradient (EFG). The quadrupole split zero-field NMR signals have also been observed in CuO. The observed frequencies yield parameter values of 137.1±0.1 MHz, 146.9±0.1 MHz, 20.07 MHz, 18.57 MHz, 0.20, 121.5 kOe, and the direction of HN is found to be nearly parallel to the direction of the maximum EFG.
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  • Site Assignment for Copper NQR Lines in Oxygen-Deficient YBa2Cu3O7−y
    Yoh Kohori, Hirofumi Shibai, Yasukage Oda, Takao Kohara, Yoshio Kitaok ...
    1988 Volume 57 Issue 9 Pages 2912-2915
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2912
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    Site assignment of copper NQR signals in the oxygen-deficient YBa2Cu3O7−y system has been performed using Gd- and SmBa2Cu3O7−y. The NQR signal around 30 MHz arises mainly from the CuO2 plane site for the 60 K superconductor, while a small amount of the signal from the CuO chain also coexists. With further decreasing the oxygen content, the intensity of the latter signal increases. Finally, the signal from the plane disappears from the NQR line around 30 MHz in the semiconducting specimens.
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  • Cationic Core Excitons in NaBr and MgBr2
    Tokuo Matsukawa, Shun-ichi Naoé, Takatoshi Murata, Masahiro Mor ...
    1988 Volume 57 Issue 9 Pages 2916-2919
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2916
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    Na-K and Mg-K soft X-ray absorption spectra have been measured with high resolution using synchrotron radiation. The results on NaBr and MgBr2 are presented. The spectral features at the absorption edges are shown to be common in character among the Na-K and the Mg-K spectra. A tentative assignment of the structures is presented. They are ascribed to cationic excitons associated with 1s to 3s and to 3p transitions in the metal ions.
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  • Link Polynomials Constructed from Solvable Models in Statistical Mechanics
    Tetsuo Deguchi, Miki Wadati, Yasuhiro Akutsu
    1988 Volume 57 Issue 9 Pages 2921-2935
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2921
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    A method, developed by the authors, to construct link polynomials from solvable models in statistical mechanics is applied to the IRF models which are associated to affine Lie algebras Am−1(1), Bm(1), Cm(1) and Dm(1). Link polynomials and reduction relations for the Am−1(1), Bm(1), Cm(1) and Dm(1) models are explicitly given. Reduction relations for the Am−1(1) model and the Bm(1), Cm(1) and Dm(1) models are quadratic and cubic, respectively.
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  • N-Soliton Solution of Two Dimensional Modified Boussinesq Equation
    Michiaki Matsukawa, Shinsuke Watanabe
    1988 Volume 57 Issue 9 Pages 2936-2940
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2936
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    We study, by the Hirota bilinear method, multi-soliton solution of Modified Kadomtsev-Petviashvili equation and of two dimensional Modified Boussinesq equation with cubic nonlinearity. It is shown first that the former has only two solition solution propagating in parallel, but the latter, two solition solution propagating in different direction under a certain condition. Independent variable transformation is also applied to the N-soliton solution of Modified K-dV equation written in the bilinear form, which is different from that obtained by Hirota, and the N-soliton solution of the 2D Modified Boussinesq equation is obtained.
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  • Green’s Function Theory of the Two-Dimensional Ising Model —Derivation of the Logarithmic Divergence of the Specific Heat—
    Takeshi Kawabe
    1988 Volume 57 Issue 9 Pages 2941-2946
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2941
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    The S=1⁄2 Ising model for a square lattice is studied by means of the two-time Green’s function method. A simple assumption is introduced associating with the rigorous relations among several spin correlation functions which are derived by this method and any approximations such as decoupling ones for the higher order Green’s functions are not used. The specific heat obtained by using this assumption shows the logarithmic divergence just below and just above Tc. It is ascertained that the theory issues only the error of order 1⁄T4 in the sum rule and in the susceptibility in the high temperature region.
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  • Longitudinal Spin Correlation in Spin-1/2 Dimerized XY Chain
    Kiyomi Okamoto
    1988 Volume 57 Issue 9 Pages 2947-2954
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2947
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    The long-distance asymptotic behavior of the longitudinal spin correlation ⟨SizSjz⟩ in the ground-state of the spin-1/2 dimerized XY chain is exactly calculated. The spin correlation ⟨SizSjz⟩ decays in the exponential law with the correlation length ξ=1⁄ln [(1+δ)⁄(1−δ)]. Here δ (0≤δ≤1) represents the degree of alternation: i.e., the stronger and the weaker spin couplings are expressed as J(1+δ) and J(1−δ), respectively. The correlation length ξ smoothly changes from ∞ (power decay) to 0 as we move away from δ=0 (no alternation) to δ=1 (independent spin pairs). The nearest neighbor spin correlation is also investigated. The present results are compared with those obtained by the use of the phase Hamiltonian method.
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  • A Molecular Dynamics Study of Relaxation Processes at a Detonation Wave Front
    Toshihiro Kawakatsu, Akira Ueda
    1988 Volume 57 Issue 9 Pages 2955-2965
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2955
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    Energy relaxation processes at a detonation wave front are studied with use of the molecular dynamics method. The model system is a hard disk system which undergoes an exothermic isomerization reaction (Remark: Graphics omitted.), where ΔQ is a reaction heat. Computations are performed for several values of the molar fraction of each species. Almost all the chemical energy of A particles is released when the detonation wave front passes. It is found that this relaxation process is composed of two kinds of time regions; one is a rapid decay process caused by non-correlated reactive collisions and the other a slow relaxation by the thermodynamic relaxation and/or the cage effect of particles.
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  • Finite Size Correction and Conformal Anomaly for O(n) Spin System
    Junji Suzuki
    1988 Volume 57 Issue 9 Pages 2966-2975
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2966
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    The finite size correction to the free energy of the critical O(n) model is calculated. With the use of the formula obtained by Blöte et al., the present result can predict the conformal anomaly of the model. In this way, the parameter dependence of the conformal anomaly predicted by Dotsenko and Fateev is confirmed in a certain parameter region.
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  • Low-Lying Excited States in 213Rn and 215Ra
    Yasuhiko Fukuchi, Tetsuro Komatsubara, Hideo Sakamoto, Takayoshi Aoki, ...
    1988 Volume 57 Issue 9 Pages 2976-2987
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2976
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    Gamma rays from low-lying levels in 213Rn and 215Ra have been studied following the 208Pb(9Be, 4n)213Rn and 206Pb(12C, 3n)215Ra reactions. Spins and parities were determined by means of the measurements of γ ray angular distributions, linear polarizations and lifetimes. Enhanced E3 transitions have been observed between the ground and the first excited state. The enhancements were as high as 38±5 for 213Rn and 34±2 for 215Ra in Weisskopf unit. The enhancement is qualitatively explained by the particle-vibration coupling model. Cascade E3 transitions have been observed in both nuclei. The role of the two-phonon octupole vibration has been examined in relation to these cascade E3 transitions.
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  • Nucleon-Nucleon Correlations and Inelastic Electron Scattering on 4He
    S. V. Dementij, A. Yu. Korchin, Eh. L. Kuplennikov, Yu. N. Ranyuk, P. ...
    1988 Volume 57 Issue 9 Pages 2988-2994
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2988
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    The differential cross sections of inclusive electron scattering on 4He are calculated with the realistic nucleon momentum distribution for 4He. The energy spectra of 4He(e, e′)X are analyzed at momentum transfers in the range of 0.3 (GeV/c)2\lesssimq2\lesssim2.4 (GeV/c)2, corresponding to the available data that have been obtained at Kharkov and Stanford. Different effects of nucleon-nucleon correlations, final-state interactions and relativistic kinematics on the reaction are investigated using so-called, y-scaling variables.
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  • Spallation of Tantalum, Tungsten and Gold by 12-GeV Protons
    Yuzo Asano, Hiroyuki Kariya, Shigeki Mori, Makoto Okano, Misao Sakano
    1988 Volume 57 Issue 9 Pages 2995-3002
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.2995
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    Formation cross sections of spallation products in the nuclear reactions of tantalum, tungsten, and gold by 12 GeV protons were measured with the γ-ray spectroscopy for 58, 73, and 80 product nuclides, respectively. The present data were used to obtain the charge-dispersion and mass-yield curves by the least-squares analysis in the mass region of product nuclides from 40 to 110 for tantalum and tungsten and from 40 to 130 for gold. The N/Z ratio at the charge-dispersion peak was determined to be approximately 1.23 for all the three targets which have the average N/Z ratio of 1.49. This result is consistent with that obtained for medium-mass targets. The mass-yield curves are compared with results of Monte Carlo simulations of an intranuclear cascade-evaporation model. They are in qualitative agreement in the mass range of the spallation products greater than a half of the target mass.
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  • State-to-State Cross Sections of Inelastic Processes in Collisions of Kr+ with N2, NO, CO and O2
    Atsushi Fukuroda, Nobuko Kobayashi, Yozaburo Kaneko
    1988 Volume 57 Issue 9 Pages 3003-3008
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3003
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    Excitation and de-excitation processes in the collisions of Kr+ with diatomic molecules have been studied with an high resolution ion energy-loss spectrometer. Absolute cross sections for the fine-structure transitions in the projectile and the vibrational excitations in the targets have been measured for N2 and NO. For CO, the cross sections of the coupled transitions of the fine-structure transitions with the vibrational excitation have been determined as well as those for the pure transitions of each of them. For O2, the cross sections of the coupled transitions of the fine-structure transitions with the vibrational and electronic excitation in the target molecules have been measured together with those of the pure transitions.
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  • Experimental Study of Current Driven Relaxation Oscillations in Heliotron E
    Hideki Zushi, Osamu Motojima, Hiroshi Kaneko, Masahiro Wakatani, Atsuo ...
    1988 Volume 57 Issue 9 Pages 3009-3019
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3009
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    In current carrying low beta plasmas heated by Ohmic current or neutral beam injection (NBI), it is found that the stability window for current driven modes exists in the range of −22<IOH⁄B0<10 kA/T. Here minus sign means that the Ohmic current flows in such a way to decrease the rotational transform in the vacuum, and this is called ‘subtractive case’. The opposite situation is called ‘additive case’. When a magnetic surface with total rotational transform (Remark: Graphics omitted.) appears near the center (IOH>17 kA at B0=1.8 T), internal disruptions are observed. On the other hand, when (Remark: Graphics omitted.) at the center is below zero (IOH⁄B0<−22 kA/T), strong MHD activities are seen. Both relaxation oscillations may be explained by a non-linear behaviour of an m=1⁄n=1 internal kink mode (additive case), and an m=1⁄n=0 resistive tearing mode (subtractive case), respectively. Here m is the poloidal mode number and n is the toroidal mode number.
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  • Mode Conversion and Electron Heating by Oblique Injection of the Ordinary Mode into Over-Dense Plasma
    Hideo Sugai, Kazuo Kikuchi, Takayoshi Okuda, F. R. Hansen, J. P. Lynov ...
    1988 Volume 57 Issue 9 Pages 3020-3028
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3020
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    An electromagnetic wave of the ordinary mode (O-mode) at a frequency near the second electron cyclotron harmonic was obliquely incident on an over-dense (ωp>ω) large-volume plasma. Two-dimensional measurements of the wave amplitude and phase suggest the occurrence of a cascade mode-conversion; the first conversion being from the O-mode to the X-mode at the critical density (ω=ωp), and the second conversion being from the X-mode to the Bernstein mode at the upper hybrid resonance. For high-power incidence, electron heating took place locally around the upper hybrid layer where the intense Bernstein-mode signals were detected. The heating was observed only for ωp\gtrsimω, supporting the theory of the cascade mode conversion.
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  • Vertex Corrections to Landau Damping of Langmuir Waves
    S. N. Sarma, R. N. Khound, S. Bujarbarua, Mitsuhiro Nambu
    1988 Volume 57 Issue 9 Pages 3029-3035
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3029
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    The vertex corrections to Landau damping of Langmuir waves in the presence of the steady electrostatic ion-cyclotron turbulences are studied. The growth rate of the Langmuir waves due to the new mode-mode coupling process (plasma-maser) is obtained through the energy up-conversion from the ion-cyclotron waves to the Langmuir waves.
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  • Ripple of Electron Temperature in R. F. Plasmas
    Susumu Takeda, Youji Hayashi, Hideki Mori
    1988 Volume 57 Issue 9 Pages 3036-3042
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3036
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    Since the electron temperature in r.f. plasmas oscillates around the d.c. one, the ripple, RT is calculated from the energy balance. Next, the electron density ripple, Rn is deduced from the difference between the ionization and diffusion loss. The frequency and pressure ranges for Rn<<RT are found, where the light intensity only follows the electron temperature, if the life time of the excited atoms is shorter than the period of the highest frequency. Then RT can be determined from the observed wave pattern of the light at a specific wave length. Here 5852.5 Å in neon and 5016 Å in herium are selected. Finally, the loss factors of electrons κ, which are determined from the experimental values of RT, are compared with the theoretical ones with a good agreement.
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  • Effects of an Ambipolar Field on Stability of Electrostatic Drift Waves in Sheet Plasmas
    M. Bashir Chaudhry, Hitoshi Hojo, Tsuguhiro Watanabe, Kyoji Nishikawa
    1988 Volume 57 Issue 9 Pages 3043-3051
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3043
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    The effects of an ambipolar field on the stability of electrostatic drift waves in sheet plasmas are investigated numerically. The analysis is based on an integral equation in the wave number space derived from the profiles of Gaussian density and parabolic ambipolar potential. The ambipolar field dependence of the eigenfrequency and eigenfunction of the drift waves is obtained. It is found that the drift waves are stabilized for a strong ambipolar potential of both the hill-type and well-type. The stabilization is due to the ion Landau damping caused by the velocity shear effect of the E×B drift. Purely growing (zero real frequency) drift modes are also found in the case of a hill-type ambipolar potential.
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  • X-Ray Diffraction Study of the Metastable Phase of Potassium Cyanide
    Yukio Yoshimura, Kohji Shimaoka
    1988 Volume 57 Issue 9 Pages 3052-3058
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3052
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    By X-ray precession photographic study, triclinic and monoclinic forms were found in the metastable phase of KCN crystal at temperatures between 165 and 158 K. These forms are mutually related with specific crystallographic orientation to the cubic lattice which is stable above 165 K. The triclinic form is a superlattice structure along the aT axis with a period of twice as much as the (110) spacing of cubic lattice, and the lattice constants are aT=9.34(1), bT=4.43(1), cT=4.56(1) Å, α=121.15(10)°, β=118.53(10)° and γ=90.00(10)° at 163 K. The lattice constants of the monoclinic form were aM=4.61(1), bM=4.58(1), cM=7.58(1) Å and β=122.27(4)° at 163 K. Crystallographic relationships between these forms and the cubic lattice are presented.
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  • Elastic Anomalies in Antiferroelectric Betaine Phosphate
    Masaki Maeda
    1988 Volume 57 Issue 9 Pages 3059-3063
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3059
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    Temperature dependences of elastic compliance coefficients s11, s22 and s33 are measured on betatine phosphate. Small anomalies are found at the structural phase transition (T1=365 K) in all the three components. At the antiferroelectric phase transition temperature (T2=86 K) a large anomaly is observed in the component s22. Below the antiferroelectric phase transition a clear step-shape anomaly is found in s22. This anomaly will be due to a new phase transition. Phenomenological theories are proposed for the structural phase transition and antiferroelectric phase transition.
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  • Molecular Dynamics Studies of Superionic Conductor CaF2
    Yutaka Kaneko, Akira Ueda
    1988 Volume 57 Issue 9 Pages 3064-3073
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3064
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    In the molecular dynamics study of the superionic conductor CaF2, the ionic soft-core system, of which the pair potential consists of the Coulombic and soft-core potentials, is investigated. The influence of the potential, especially of the softness of the soft-core repulsion, on the distribution of anions and diffusion paths is studied. We also study the dynamics of the diffusion in comparison with those of α-AgI. Anions diffuse from a well-defined site to sites with strong correlation among neighboring anions. In contrast to the case of α-AgI, both the Coulomb and soft-core forces between anions are shown to be responsible for the diffusion. It is also shown that the vibrational properties of mobile and immobile ions are quite different from those of α-AgI.
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  • Holes in Two-Dimensional CuO2 System —Pairing Mechanism Emerging from Small-Cluster Studies—
    Masao Ogata, Hiroyuki Shiba
    1988 Volume 57 Issue 9 Pages 3074-3088
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3074
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    The strongly correlated two-dimensional CuO2 model is studied to identify the pairing mechanism of holes. Detailed studies of the ground state of clusters up to 30 atoms (10 Cu and 20 O atoms) reveal a binding of two holes doped on oxygen sites for particular values of parameters, which appear relevant to high-Tc superconductors. The wave function for the ground state shows that a doped hole on oxygen couples strongly with two neighboring Cu spins, which in turn causes a large magnetic distortion in the surrounding Cu spin system. The interaction between two holes becomes attractive through a constructive interference of the magnetic distortions.
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  • Interference between Superconductivity and Martensitic Transition in A15 Compounds
    Naoki Toyota, Tsukasa Kobayashi, Mitsuo Kataoka, Hirohide F. J. Watana ...
    1988 Volume 57 Issue 9 Pages 3089-3101
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3089
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    An interference effect between the high-Tc superconductivity and martensitic transition in A15 compounds such as V3Si and Nb3Sn has been studied. It is found from the measurements of the sound velocity, sound attenuation, thermal dilation and the electrical resistance, that an occurrence of superconductivity interferes drastically with the developing tetragonal distortions caused by the martensitic transformation, but the high-Tc superconductivity in these compounds is only weakly affected by the presence of the martensitic transition. This unilateral interference effect is qualitatively consistent with the second-order band Jahn-Teller mechanism which means the Fermi level crossing the upper split band of the doubly degenerate Γ12 subbands. Discussions on Tc are given on the basis of the Fermi surface effect of Γ12 subbands.
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  • Theory of NMR in Superconducting Multilayers
    Kazuhiro Kuboki, Hidetoshi Fukuyama
    1988 Volume 57 Issue 9 Pages 3102-3111
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3102
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    Motivated by experiments of NMR on superconductor(S)-normal-metal(N) multi-layer system, we have calculated the nuclear spin-lattice relaxation rate, T1−1, for both N and S layers based on the bilayer model of McMillan for the proximity effect. The results of calculation are in essential agreement with experiments by Aoki et al. and Imai et al.
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  • Pressure Effect on the Magnetic Properties of Hf1−xTaxFe2
    Kensuke Hoshi
    1988 Volume 57 Issue 9 Pages 3112-3118
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3112
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    The effect of pressure on the magnetic phase transition temperature of Hf1−xTaxFe2 with x=0 and x=0.1 has been studied. The Curie temperature for x=0 decreases with increasing pressure at a rate of −(1.2±1.0) K/kbar, and for x=0.1 it decreases with a pressure coefficient of −7.5 K/kbar up to about 8 kbar and above 8 kbar two magnetic phase transitions, one being of the first order and the other of the second order, are induced by applying pressure. The former is a phase transition from a ferromagnetic to an antiferromagnetic phase. The transition temperature decreases at a rate of −10.0 K/kbar. The latter is a phase transition from an antiferromagnetic to a paramagnetic phase. The transition temperature decreases at a rate of −5.1 K/kbar. These results under pressure are compared with the results obtained by partial substitution of Ta for Hf in HfFe2.
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  • Magnetic Susceptibility of Metal-Insulator System LixZn1−xV2O4
    Muhtar , Fumio Takagi, Kazuhiko Kawakami, Nobuo Tsuda
    1988 Volume 57 Issue 9 Pages 3119-3127
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3119
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    The magnetic susceptibilities of LixZn1−xV2O4 were measured from 80 K to 1100 K. They apparently follow the Curie-Weiss law above and below about 500 K, separately, with different constants. Above about 500 K, they show similar susceptibilities irrespective of their transport properties. Below about 500 K, the Weiss temperatures of metallic oxides are nearly zero. The susceptibility of insulating ZnV2O4 becomes smaller than an extrapolated one, and it suggests a decrease in the effective moment. To explain the conductivity dependent Weiss temperature, a spin orienting interaction by mobile electrons was considered. The decrease of the effective magnetic moment was attributed to the Fermi statistics of quasi-itinerant electrons which extend over a certain range in a periodic lattice.
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  • A Quantum Simulation Study of Superconducting Correlation in Electron Systems with Strong Correlation
    Masatoshi Imada
    1988 Volume 57 Issue 9 Pages 3128-3140
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3128
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    Quantum simulation results of superconducting correlations for strongly correlated electron systems are reported. An extended-type Hubbard model to take account of the role of oxygen sites in the CuO2 plane of high-Tc oxides is studied primarily. Superconducting susceptibility shows a tendency of quantitative enhancement at lower temperatures in contrast with the case of the single-band Hubbard model. It shows that a coupled two-band system, one with strong and the other with weak correlation, is favorable for superconductivity. A possible connection between superconducting and antiferromagnetic correlation is also discussed.
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  • Giant Spin Fluctuations in Y0.97Sc0.03Mn2
    Masayuki Shiga, Hirofumi Wada, Yoji Nakamura, J. Deportes, B. Ouladdia ...
    1988 Volume 57 Issue 9 Pages 3141-3145
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3141
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    Paramagnetic scattering using polarized neutrons has been measured on Y0.97Sc0.03Mn2 which is a Pauli paramagnet with remarkable spin fluctuation effects. The wave vector dependence of scattering indicates a strong antiferromagnetic correlation. The energy analysis of the scattering has revealed that a substantial part of the scattering is caused by zero point fluctuations. The amplitude of thermally excited local spin fluctuations has been estimated as a function of temperature.
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  • Magnetic Field Effects on the Specific Heat of Nearly Ferromagnetic Metals
    Shigeo Shioda, Yoshinori Takahashi, Tôru Moriya
    1988 Volume 57 Issue 9 Pages 3146-3156
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3146
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    The magnetic field dependence of the specific heat due to spin fluctuations in nearly ferromagnetic metals is quantitatively discussed over the wide temperature and field ranges based on the self-consistent renormalization theory of spin fluctuations. It is shown that for TiBe2, good agreement is obtained between the theory and experiment both for the susceptibility and the specific heat.
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  • Nuclear Magnetic Resonance of GdCo3
    Hiroshi Yoshie, Yoji Nakamura
    1988 Volume 57 Issue 9 Pages 3157-3160
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3157
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    The nuclear magnetic resonance of 59Co nuclei in magnetic domains of GdCo3 has been measured under external magnetic fields up to 55 kOe at 4.2 K. In order to assign the observed NMR signals to each Co site, the 59Co nuclear magnetic resonance of Gd(Co1−xTx)3, where T stands for Ni and Fe, has also been measured under the same conditions. The 59Co hyperfine fields at the 3b, 6c and 18h sites in GdCo3 have been measured as 80 kOe, −58 kOe and −80 kOe, respectively. The orbital contribution to the magnetic moment of Co atoms in YCo3 is also discussed from NMR and neutron diffraction data.
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  • Double Resonance Inversion Recovery in a Heteronuclear Two Spin System
    Mitsumasa Ishiwata, Jun-ichi Koizumi
    1988 Volume 57 Issue 9 Pages 3161-3171
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3161
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    For a heteronuclear coupled AX spin system, recovery after inversion of the A spin lines in A−{X} double resonance spectra is observed under a spin tickling condition. Oscillations in the A lines after inversion are found to decay more rapidly than expected and depend on inhomogeneity of an applied static field. After the initial oscillating stage, the recovery of the tickling spectra can considerably be accelerated by an irradiation field which is applied near a resonance of an X line. A simple mathematical method is presented for calculating the double resonance recovery process under the inhomogeneity of the static field. Such an inhomogeneity modifies a recovery time near the resonance. Experimental results for 13C-enriched formic acid are reproduced by numerical computation. Acceleration of the recovery is explained in terms of a saturation effect of the irradiated line.
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  • Mössbauer Diffraction Spectra in Partially Ordered Ni3Fe Alloy
    Yutaka Nakai, Yoshiharu Ooi, Nobuhiko Kunitomi
    1988 Volume 57 Issue 9 Pages 3172-3177
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3172
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    The Bragg reflections due to nuclear resonant scattering (Mössbauer scattering) have been observed in a partially ordered Ni3Fe alloy. The system has a wide distribution of the resonant energy for Mössbauer γ-rays due to the variety of environmental conditions. The observed spectra are well reproduced by the simple theoretical formulae as a function of the Doppler velocity.
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  • Nuclear Spin-Lattice Relaxation Mechanism of Singlet-Ground-State Magnet with Exchange Coupling: Application to CsFeCl3
    Meiro Chiba, Yoshitami Ajiro, Kimio Adachi, Takeshi Morimoto
    1988 Volume 57 Issue 9 Pages 3178-3187
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3178
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    A model is proposed on the exchange coupled singlet-ground-state magnet around the level crossing field. The model starts from the energy level of the isolated single spin in paramagnetic spin system. The effect of the exchange coupling is taken into account by modifying the single ion level scheme to the broadened continuum band. On the basis of this model is discussed a mechanism of the nuclear spin-lattice relaxation inherent in the level crossing, due to the direct process between the nuclear spin and the exchange coupled electron spin system. A drastic increase of the nuclear spin-lattice relaxation rate of 133Cs in CsFeCl3 observed at 4.2 K around the level crossing field at 7.5 T is well explained by this model. The magnetization as a function of external magnetic field is also discussed and compared with the result of CsFeCl3 up to 12 T.
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  • Field Enhancement in a Spherical Cavity beneath a Metal Surface
    Tadashi Takemori, Masahiro Inoue
    1988 Volume 57 Issue 9 Pages 3188-3197
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3188
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    We have solved Maxwell’s equation around a spherical cavity just beneath a flat surface of a Ag substrate. We use dielectric constant by Johnson and Christy. A strong field enhancement is found on a small area of cavity surface closest to the substrate surface where the metal layer is thin. The enhancement mechanism is the induced surface plasma oscillation on the thin Ag layer. Raman enhancement factor of order 104 is found for a cavity of radius 100 A centered 110 A beneath the substrate surface.
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  • Hyper-Raman Study of Ferroelectric Phase Transition of Li2Ge7O15
    Yoshiyuki Morioka, Mitsuo Wada, Akikatsu Sawada
    1988 Volume 57 Issue 9 Pages 3198-3203
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3198
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    The ferroelectric phase transition of Li2Ge7O15 was investigated by means of the hyper-Raman scattering. The under damped soft mode was observed at temperatures above 305 K in the paraelectric phase. In the further lower temperature region, an unresolved central peak is observed. The temperature dependence of the intensity of the central peak is characterized by the diverging behavior near the transition temperature and the linear increase with decreased temperature in the ferroelectric phase. These can be attributed to the hyper-Raman scattering due to the polarization fluctuation, and the optical second harmonic generation which becomes active in the ferroelectric phase, respectively.
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  • Spatical Distribution and Dynamics of Excitons in Anthracene Crystals
    Yasuo Nozue
    1988 Volume 57 Issue 9 Pages 3204-3219
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3204
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    The excitation spectra of the excitonic luminescence bands in anthracene crystals are investigated in detail. The experimental results at 2 K are interpreted by the diffusion of exciton polaritons. At room temperature, those are interpreted by the exciton diffusion and the luminescence reabsorption. The diffusion lengths of excitons at 2 K and room temperature are determined to be 30±1 and 30±5 nm for the direction perpendicular to the ab-plane of the crystal, respectively. These values are several orders smaller than that determined by the measurement of the time resolved luminescence spectra. The discrepancy is interpreted by introducing the exciton transfer process caused by the luminescence reabsorption. The temperature and the sample-thickness dependences of the luminescence decay-time are also interpreted self-consistently by the same model.
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  • Raman Scattering Study of Scheelite-Type Double Molybdates
    Kazuhiro Hara, Hiromitsu Takenaka, Yoshihiro Ishibashi
    1988 Volume 57 Issue 9 Pages 3220-3225
    Published: September 15, 1988
    Released on J-STAGE: May 29, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3220
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    Raman scattering measurements were performed to investigate optical modes of scheelite-type double molybdates XY(MoO4)2 (X=Li, Na and Y=La, Nd). In the polarized Raman scattering measurements, we have found four modes in NaLa(MoO4)2, one in low frequency region (with Bg symmetry) and three in high frequency region, which are missing in the previous observation by Ramakrishnan. The scattered light by the high-frequency modes does not show clear polarization characteristics. By the drastic modification of these modes with changing the proportion x of NaxLa(4−x)⁄3(MoO4)2, we concluded that the newly found high-frequency modes result from the local deformation caused by the random positioning of the X+ and Y3+ ions.
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  • A Study on Z3-Exciton’s Damping in CuCl1−xBrx Solid Solutions
    Kenji Funato, Nobukata Nagasawa
    1988 Volume 57 Issue 9 Pages 3226-3232
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3226
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    An ω-dependent damping factor of Z3-exciton in CuCl1−xBrx (x≥0.012) has been evaluated experimentally, using two-photon resonant Raman scattering (TRRS) based on two-photon excitation of excitonic molecules and linear reflection. A remarkable difference between the shape of the observed reflection spectrum and the corresponding spectrum calculated from the polariton dispersion curve, which was determined experimentally by TRRS for the same sample, has been found in the L–T gap region of Z3-exciton of the sample of x=1.2×10−2. The difference has been analyzed as the ω-dependence of the damping factor of the exciton level. Its x-dependence has also been studied.
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  • Temperature Dependence of Positron Annihilation in Plastically Deformed Copper
    Eiji Hashimoto, Takeshi Shiraishi, Nobuo Kamigaki, Takao Kino
    1988 Volume 57 Issue 9 Pages 3233-3238
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3233
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    Doppler-broadened photopeaks resulting from positron annihilation in as-deformed and recovered copper crystals were measured as a function of temperature between 4.2 and 275 K. In the as-deformed state, a significant line narrowing for increasing temperature was observed in the range below about 100 K. This low-temperature effect was removed by recovery annealing up to 573 K, at which the annealing out of dislocations had taken place. The results from the as-deformed state were explained in terms of thermal detrapping of positrons from shallow traps along the dislocation line, with subsequent retrapping either at submicroscopic vacancy clusters or deeper traps associated with dislocations. An activation energy for detrapping was estimated to be less than 0.01 eV.
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  • Temperature Dependence of the Polarized Reflectance Spectra of the θ-Type of Bis(ethylenedithio)tetrathiafulvalenium Triiodide θ-(BEDT–TTF)2I3: Estimation of Band Parameters
    Masafumi Tamura, Kyuya Yakushi, Haruo Kuroda, Akiko Kobayashi, Reizo K ...
    1988 Volume 57 Issue 9 Pages 3239-3247
    Published: September 15, 1988
    Released on J-STAGE: June 01, 2007
    DOIhttps://doi.org/10.1143/JPSJ.57.3239
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    Polarized reflectance spectra in the region from 720 cm−1 to 25000 cm−1 were measured on the single crystal of θ-(BEDT–TTF)2I3, an organic superconductor, at temperatures over 16–295 K. A Drude-like spectrum was found for the first time in metallic BEDT–TTF salts. This characteristic spectrum was attributed to the unique structure of the θ-type crystal. The curve-fitting analysis of the spectra gave the plasma frequencies (ωp)a=1.05 eV and (ωp)c=0.73 eV at 16 K, from which the anisotropic effective masses were evaluated to be ma*=1.5me and mc*=3.0me. The transfer integrals and other band parameters of the tight-binding band were directly derived from the analysis of the optical data. The transfer integrals thus obtained are ta=0.080 eV and tc=0.046 eV. These results are to be compared with the calculated band structure.
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