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Tohru Yoneyama
1986Volume 55Issue 11 Pages
3691-3693
Published: November 15, 1986
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Interacting (Int) nonlinear Schrödinger (NLS) equations is a system of coupled nonlinear differential equations which is derived from the original NLS equation by an interacting soliton picture. By examining possible relations between a soliton solution
ui which obeys the Int NLS equation and the solutions of the two-component equations which appear in the inverse method, we obtain the form of the natural Int NLS equations. We use only the knowledge of the forms of the equations concerned. The resulting form is different in several points from those of the other equations already treated i.e. the Korteweg-de Vries (KdV), sine-Gordon, modified KdV, Toda and Benjamin-Ono equations.
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Kazuo Hida
1986Volume 55Issue 11 Pages
3694-3697
Published: November 15, 1986
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The behavior of the rf-current driven Josephson junction is studied in the presence of quantum fluctuations in the semiclassical regime by the quantum Langevin equation. It is found that the onset of chaos is suppressed quite sensitively by the introduction of the quantum noise.
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Kazuo Hida
1986Volume 55Issue 11 Pages
3698-3700
Published: November 15, 1986
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The mobility of the damped sine-Gordon soliton with the damping constant
Γ is calculated up to the first order in temperature in the presence of the frequency cut-off ω
c in the spectrum of the heat bath. The first order finite temperature correction turns out to be different in the two limiting cases: (I) ω
c→∞,
Γ→∞ with ω
c⁄
Γ→0 and (II) ω
c→∞,
Γ→∞ with ω
c⁄
Γ→∞. It is also found that the first limit corresponds to the mobility of the overdamped sine-Gordon model without inertia calculated by Kaup and the second to that of the heavily damped limit of the damped sine Gordon model with inertia calculated by Kaup and Osman both assuming the white noise spectrum. Our result gives the physical interpretation of the discrepancy between these two calculations.
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Hiroshi Oshiyama, Masahiko Goto, Shoi Kho, Shokyo Kho, Hiroshi Ichida
1986Volume 55Issue 11 Pages
3701-3704
Published: November 15, 1986
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An axisymmetric reversed-field pinch (RFP) configuration is analyzed by minimizing a potential energy of a plasma, subject to the Woltjer’s invariant
K and the invariants of both a longitudinal flux
Φ and a poloidal flux χ, as well as a reasonable boundary condition of
J=0 on the wall. An equilibrium equation,
J×
B=grad
p is also taken as the local constraint. The obtained RFP configuration has the high beta value of 17.7% on the axis and satisfies the Suydam’s criterion as well as the ideal MHD and tearing mode stability criterion for the
m=1 mode. In this RFP, the field reversal ratio
F and pinch ratio θ are about −1.2 and 2.48 respectively. The components of the magnetic fields,
Bθ and
Bz are also given in analytical expressions.
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Kiyomitsu Suzuki, Shigeo Hamada
1986Volume 55Issue 11 Pages
3705-3708
Published: November 15, 1986
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Field reversed configurations in recent experiments such as FRX–C, OCT and NUCTE are numerically studied by solving the Grad-Shafranov equation. The beta profiles used in the calculation have been inferred from the experimental data with use of one dimensional model of FRC. The calculated values of the separatrix radii well agree with the experimental data and the surfaces of flux null have been confirmed to be closed in each experiment.
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Toshiyuki Ninomiya
1986Volume 55Issue 11 Pages
3709-3712
Published: November 15, 1986
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The structure of one-dimensional quasicrystal is reconsidered so that we can intuitively understand its electronic properties. It is shown that the Fibonacci sequence is obtained from a regular crystal by successive application of periodic modulations, which have the periods increasing as
n,
n2,
n3, … (
n=3) and are self-similar. Explanations are given for the peculiar spectra of electronic states on a one-dimensional quasiperiodic lattice as a result of the modulations applied to the crystal. Differences are also briefly discussed for the phonon and electronic band structure.
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Kiyomi Okamoto
1986Volume 55Issue 11 Pages
3713-3716
Published: November 15, 1986
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The critical behavior of the paraconductivity of Hg
3−δAsF
6 is calculated on the basis of the model recently proposed by Sugiyama, Gutfreund and Weger [J. Phys. C
19 (1986) 2519]. In contrast to their result, the paraconductivity behaves as ε
−1⁄2 with ε=ln (
T⁄
Tc), which is characteristic of three dimensional systems. The correlation length, the linearized TDGL equation and the GL free energy density up to |
Δ|
2 are also obtained.
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Yasumasa Hasegawa, Hidetoshi Fukuyama
1986Volume 55Issue 11 Pages
3717-3720
Published: November 15, 1986
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The strong reduction of the critical temperature,
Tc, of organic superconductors (TMTSF)
2PF
6, irradiated by X-ray is shown to be understood within the framework of dirty singlet superconductors in the weakly localized regime; i.e. the enhancement of the Coulomb repulsion due to randomness. In the case of the proton-irradiation the reduction of
Tc experimentally observed is larger and may be ascribed to magnetic defects as suggested before. In the system with two superconducting states such as (BEDT–TTF)
2I
3 relative reduction of
Tc should depend on whether it is caused by the localization effect or by the pair breaking with magnetic defects, and then the origin of the reduction will be identified.
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Nobuyoshi Yamada, Koichiro Maeda, Yoshihisa Usami, Tetuo Ohoyama
1986Volume 55Issue 11 Pages
3721-3724
Published: November 15, 1986
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Magnetic properties of an orthorhombic intermetallic compound Mn
11Ge
8, which was formerly referred to as Mn
3Ge
2, has been investigated on a single crystal specimen at temperatures between 80 K and 800 K. The compound has features of a non-collinear antiferromagnet below
Tt=150 K, and makes a spin-flopping transition when magnetized along the
c axis. It becomes ferromagnetic with a first order transition at
Tt with the direction of easy magnetization lying along
b axis up to its Curie temperature 274 K. The susceptibility follows the Curie-Weiss law above 550 K, with asymptotic Curie temperature 329 K and effective Bohr magneton number per Mn
Peff=3.26.
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Kazuyoshi Takeda, Kuniyuki Koyama, Kazuo Yamagata
1986Volume 55Issue 11 Pages
3725-3728
Published: November 15, 1986
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Effects of compression and magnetic dilution on the first and second order phase transitions have been examined with Mn(HCOO)
2·2H
2O, which exhibits both of the spin axis reorientation at
TR=1.70 K and the antiferromagnetic transition at
TN=3.69 K. The application of hydrostatic pressure (
p) makes a clear shift of
TN(
p) (d
TN(
p)⁄d
p=+0.022
TN(
p0) K·kbar
−1;
p0\simeq0 kbar) preserving a sharp heat capacity peak. However, the transition at
TR(
p0)=1.70 K becomes quite obscure in the pressure with a broadening of the heat capacity peak around
TR(
p)(d
TR(
p)⁄d
p=+0.078
TR(
p0) K·kbar
−1). These phenomena are compared with the phase transitions in the magnetically diluted system with Zn
2+ ions.
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Tetsuro Saso, Yutaka Seino
1986Volume 55Issue 11 Pages
3729-3732
Published: November 15, 1986
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Quantum Monte Carlo[MC] calculation of one-dimensional periodic Anderson model without orbital degeneracy is performed by use of the path-integral formulation. Local
f moment coincides well with the recent MC calculation for single impurity by Hirsch and Fye above the temperature at which antiferromagnetic correlation starts to grow, and decreases faster than those for single impurity and coupled two impurities below that temperature. Overall features, including susceptibilities, resemble one-dimensional Hubbard model with half-filled band.
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Kiyoichiro Motoya
1986Volume 55Issue 11 Pages
3733-3736
Published: November 15, 1986
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Neutron diffraction and magnetic susceptibility measurements were performed on a series of pseudobinary intermetallic compounds Y(Mn
1−xAl
x)
2. Antiferromagnetic order being developed in YMn
2 has been shown to collapse by substitution of no more than 5% of manganese atoms by aluminum atoms. Growth of broad peaks in neutron diffraction patterns at low temperatures and field hysteresis behavior observed in magnetic susceptibility measurements indicate a development of
a short range correlated spin glass phase.
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Toshimasa Uemura, Yoshiaki Chiba, Masayuki Hagiwara, Muneyuki Date
1986Volume 55Issue 11 Pages
3737-3740
Published: November 15, 1986
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Electron spin resonance (ESR) of disordered Sm ion located at the B
6-cluster site in SmB
6 is observed. Various valence states such as Sm
3+, Sm
2+, Sm
0, Sm
− and Sm
2− are found. It becomes clear that there are two ways of electron trapping on the disorder site. One of them is the 4f-trap where additional electrons occupy the vacant 4f-level of the disordered Sm with the Hund rule. On the other hand, weakly coupled donor electrons exist in addition to the 4f level electrons. Two possibilities of the coupling model are discussed.
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Yasufumi Fujiwara, Yasushi Kita, Yoshiyuki Tonami, Taneo Nishino, Yosh ...
1986Volume 55Issue 11 Pages
3741-3744
Published: November 15, 1986
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A series of new zero-phonon luminescence lines has been for the first time observed in the 0.837 eV region besides the well-known Cr-related luminescence lines in Cr, Se-codoped GaAs. The in-depth profiles of these luminescence intensities have suggested that the new luminescence lines originate from a Cr–Se complex. Furthermore, from analysis of the peak position together with those of the Cr–Te and Cr–V
As luminescence lines, it has been found that the trigonal field at the Cr–Se complex is weaker by about two times than that at the Cr–Te complex and by about four times than that at the Cr–V
As complex.
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Wataru Niiyama, Kenji Miyakawa
1986Volume 55Issue 11 Pages
3745-3748
Published: November 15, 1986
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The effects of temperature on the rhythm of heartbeats of chick embryos are studied at the 11∼16 somite developmental stages. The rhythmic recurrence of heartbeats is found to be decreased in frequency as the temperature decreases. This behavior is found to be described as ν∝exp (−
W⁄k
T), where
T is the absolute temperature, k is the Boltzmann’s constant and ν is the frequency of heartbeats. The variabl
W can be interpreted as the minimum activation energy necessary for one heartbeat, the magnitude of which increases with the developmental stage.
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Shigeki Tasaka, Teruhiro Suda
1986Volume 55Issue 11 Pages
3749-3752
Published: November 15, 1986
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A 80 m
2 detector array consisting of two layers of CR-39 plastic track detector and an iron absorber was exposed at deep underground (2700 m.w.e.) in Kamioka mine for 1.8 yr. This plastic plate can detect tracks of penetrating monopoles with energy loss rate greater than that of a neucleus with
Z⁄β\gtrsim10. Considering recoil of the C and O atoms in CR-39 due to diamagnetic repulsion, CR-39 plastic detector is considered to be sensitive to the monopoles at velocities down to about 10
−4 c. We have found no monopole candidate, and this implies that the upper limit on the flux of grand-unified-theory monopoles with
v∼10
−4 c or
v>5.5×10
−3 c is 3.0×10
−14 cm
−2s
−1sr
−1 at 90% confidence level.
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E. V. Krishnan
1986Volume 55Issue 11 Pages
3753-3755
Published: November 15, 1986
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For the Ito-type coupled nonlinear wave equation, some exact solutions are given in terms of Weierstrass elliptic functions.
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Yuji Ishimori, Norichika Miyamoto
1986Volume 55Issue 11 Pages
3756-3767
Published: November 15, 1986
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Dynamical behaviors of vortices of the two-dimensional Gross-Pitaevskii and Higgs equations are numerically investigated and are related to nonintegrability of the equations such as orbital instability and ergodicity. Two kinds of experiment are made. (1) Collisions of the vortices are studied to show that the collisions are inelastic and produce the orbital instability. (2) Low Fourier modes are initially excited, and the following phenomena are observed. At high energy state creation and annihilation of the vortices take place and the orbits in the phase space are unstable. Furthermore, the kinetic energy is distributed to many Fourier modes. On the other hand, at low energy state no vortex is excited and the properties of nonintegrability are not found.
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Shogo Nakaya, Kazuo Hida
1986Volume 55Issue 11 Pages
3768-3777
Published: November 15, 1986
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We investigate the tunneling rate from metastable state induced by the external applied field in the nonlinear Klein-Gordon system with dissipation. By the scaling argument, it is shown that the effective dissipation becomes strong as the external field approaches the classical depinning field and qualitatively changes the external field dependence of tunneling rate. For arbitrary strength of the effective dissipation, the tunneling rate is obtained by the variational method.
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Yoshiko Narita, Ikuo Ono, Takehiko Oguchi
1986Volume 55Issue 11 Pages
3778-3785
Published: November 15, 1986
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Monte Carlo simulations in the fully frustrated simple cubic Ising lattice are carried out by introducing new order parameters which represent the wrong-bond distribution. Two phase transitions are observed near
kT⁄
J=1.3 and
kT⁄
J=0.8. Below
kT⁄
J=1.3, the Kosterlitz-Thouless-like phase is indicated by estimating the critical exponent η. The one dimensional ordering is found below
kT⁄
J=0.8. The third phase transition is suggested near
kT⁄
J=0.5.
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Masayuki Nakahata, Katsushi Arisaka, Takaaki Kajita, Masatoshi Koshiba ...
1986Volume 55Issue 11 Pages
3786-3805
Published: November 15, 1986
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The main source of background for nucleon decay experiments is the interaction of atmospheric neutrinos in the detector. To estimate this background a Monte Carlo program was developed, which simulates the neutrino interactions and the nuclear effects of secondary pions. The program reproduced existing neutrino data as well as global features of the contained events in the KAMIOKA nucleon decay experiment. Neutrino induced background for nucleon decay was then calculated.
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Jiro Arafune, Nobuaki Koga, Keiji Morokuma, Tadashi Watanabe
1986Volume 55Issue 11 Pages
3806-3812
Published: November 15, 1986
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Molecular effects on the β-ray spectra of triton decay are carefully estimated for two alkane molecules, CH
3T and CH
3–CHT–CH
3 in the sudden approximation by
ab initio SCF–MO methods. (1) The basis set dependence of transition probabilities is examined for CH
3T using four types of basis sets of the double zeta quality with and without diffuse and polarization functions. (2) The excitation energy spectrum for the transition of CH
3–CHT–CH
3 is shown to have two broad peaks at ∼20 eV and 35 eV corresponding to the molecular excitations, which is rather similar to the distribution for valine II obtained by Kaplan
et al. (3) The validity of the adopted basis set is also checked for the case of propane by examining the saturation of the unitarity and of the sum rules for the excitation energy. The rate of the two-particle excitation turns out to be 4.8%, the inclusion of which improves the saturation of the unitarity to 98.6%.
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Jiro Arafune, Nobuaki Koga, Keiji Morokuma, Tadashi Watanabe
1986Volume 55Issue 11 Pages
3813-3818
Published: November 15, 1986
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The lowest order correction to the sudden approximation is formulated for the molecular transition amplitude in triton decay by taking account of the Coulomb interaction of the ejected β ray with residual charged particles. The effect is of the order of (α⁄β
e)
2 with β
e the β-electron velocity. The transition probabilities for propane are explicitly calculated by an
ab initio SCF–MO method and the modification is shown to be at most 0.6% for those in the sudden approximation.
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Yukio Koike, Tsuneo Kaneko, Morikazu Nomoto
1986Volume 55Issue 11 Pages
3819-3824
Published: November 15, 1986
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We investigate the distortion effects of the deuteron during the
28Si(d, d)
28Si scattering and
28Si(d, p)
29Si reaction. The calculated results show that the deuteron shrinks as often pointed out and the binding energy decrease rapidly in the inner part of the target nucleus. The distortion effects of the incident deuteron appear clearly in the elastic scattering and reaction.
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Mikihiko Hirono
1986Volume 55Issue 11 Pages
3825-3830
Published: November 15, 1986
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The CO
2 absorption measurements have been carried out using an infrared spectrometer at pressures up to 50 atm in the 2.7 and 4.8 μm regions. By using the Wilson-Wells-Penner-Weber method, the values of band intensity have been found to be 73.1±1.8 cm
−2 atm
−1 at STP and 0.174±0.008 cm
−2 atm
−1 at STP for the 2.7 and 4.8 μm bands respectively. The calculated spectral absorptances by line-by-line procedures were also compared with the experimental results to check the validity of our band intensiy values.
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Tomohisa Nakamura, Nobuo Kobayashi, Yozaburo Kaneko
1986Volume 55Issue 11 Pages
3831-3840
Published: November 15, 1986
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Excitation and de-excitation processes in the collisions of Ar
+(
2P
J) with H
2 and N
2 were studied below 2 keV by high resolution ion energy-loss spectroscopy. For both systems, fine structure transitions between the different
J states of Ar
+, vibrational excitations of target molecules for fundamental and harmonic mode were observed. In addition to them, coupled transition of fine structure transition and vibrational excitation were observed. Cross sections were determined for all the transitions observed. The measured cross sections align in the reciprocal order of the energy defect
ΔE. This simple
ΔE-dependence is explained well by the assumption that all the transition take place through the two step process via charge transfer channel as an intermediate state.
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Norihiko Nakauchi, Setsuko Sega
1986Volume 55Issue 11 Pages
3841-3850
Published: November 15, 1986
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Mixing of two scalars in isotropic turbulence is studied by using the modified zero-4th-cumulant (MZFC) expansion. The dynamical equations of scalar fluxes and covariance spectra are formulated by the MZFC approximation under the assumption of homogeneous axisymmetric diffusion of scalar, and are solved numerically to examine the behavior of their spectra. Particular attention is paid to an axisymmetric effect of scalar fluxes on the covariance. The numerical result shows that when two scalar-fluxes exist in turbulent flows, they induce the anisotropy covariance so that the two-scalar covariance increases in the direction of a symmetric axis and decreases in the direction transverse to it.
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Youichi Murakami
1986Volume 55Issue 11 Pages
3851-3856
Published: November 15, 1986
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The linear stability of uniform solutions of a complex nonlinear Klein-Gordon equation
Att−
Axx−
GA−
N|
A|
2A=0, where
G and
N are real coefficients, is investigated. Two kinds of uniform solutions are treated: one is a wave train solution
a0 exp (
iσ
t) where
a0 is a constant real amplitude; the other is a temporally periodic solution in terms of Jacobian elliptic function. The former is found to be unstable in the subcritical state (i.e.
G<0,
N>0); the latter is found to be unstable in both subcritical and supercritical (i.e.
G>0,
N<0) states. The stability digrams are given in both cases.
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Toshio Funada, Masahiro Kotani
1986Volume 55Issue 11 Pages
3857-3862
Published: November 15, 1986
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A nonlinear diffusion equation governing a surface deformation, which has been derived theoretically for the Marangoni convection, is investigated numerically. By solving an initial value problem under a periodic boundary condition, it is found that the numerical solutions for the surface deformation are classified into three types, i.e., damping, steady and explosive ones depending upon various values of parameters.
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Takeo Soga
1986Volume 55Issue 11 Pages
3863-3871
Published: November 15, 1986
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The Boltzmann equation with the Gross-Jackson’s collision model, i.e., the Gross-Jackson’s model equation was solved by applying the half-range Hermite polynomials. It was found that the solution to the model equation converged rather rapidly as long as the scaling factor β was of 0(1). The rate of the convergence seemed to be dependent on the value of β but if the collision term included sufficient eigen-values to the Boltzmann collision operator, the solution was, in practice, independent of the value of β. The velocity slip coefficient obtained showed a good agreement with the result of the direct Monte Carlo simulation to the full Boltzmann equation.
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Mitsuaki Nagata
1986Volume 55Issue 11 Pages
3872-3878
Published: November 15, 1986
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The momentum transfer term for the case of isotropic scattering is generalized into one for a case of anisotropic scattering. We deal with a perfectly ionized hydrogen plasma as a medium in which the scattering is anisotropic. We have improved the long procedure through which the momentum transfer term in a slightly ionized plasma had been derived, and have easily arrived at a more general expression.
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Shigeru Hayashi, Yoshihiro Simazu, Nobuhiro Harada, Hiroyuki Yamasaki, ...
1986Volume 55Issue 11 Pages
3879-3888
Published: November 15, 1986
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Relaxation of a stationarily flowing jet-like plasma, which penetrates into a neutral gas with temperature and kinetic energy much lower than the ionization potential, is investigated experimentally by measuring spatial distributions of hydrodynamic quantities such as plasma flow velocity, electron temperature and density in the plasma-neutral gas interaction zone. The experimental results agree with calculations. The particle, momentum and energy conservations of the plasma in the interaction zone are dominated by diffusion, ion elastic collision with neutral atoms and ionization, respectively.
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Yasutomo Ohguchi, Kengo Takahama
1986Volume 55Issue 11 Pages
3889-3893
Published: November 15, 1986
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Dynamics of the nonlinear circuit including the atmospheric pressure hydrogen discharge tube are examined to study phenomena around the arc-glow transition region on the basis of the static multivalued
V-
I characteristics, which are supposed from the results of experiments and theories. Although the multivaluedness leads to oscillations, the ranges of voltage and current of the oscillations do not agree with those observed experimentally. In a new experiment using a power supply with a stabilization circuit, the oscillations appeared in the previous experiments are suppressed and the static
E-
I characteristics which are characterized by a monotonical curve are obtained.
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Mitsuyasu Yatsuzuka, Keiichi Morishita, Kikoh Satoh, Sadao Nobuhara, K ...
1986Volume 55Issue 11 Pages
3894-3902
Published: November 15, 1986
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An electron beam modulated near the lower-hybrid frequency is injected into a target plasma immersed in a longitudinal magnetic field. The parametric excitation of the electrostatic ion cyclotron wave and lower-hybrid wave is observed. The threshold and the excited wave potentials are measured by the use of a capacitive probe with a small tip capacitance. Substantial heating of ions and electrons is observed with growth of the instability. Such a rapid heating of ions is ascribed to the electrostatic ion cyclotron wave.
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Tomoyuki Sekine, Michio Takayama, Kunimitsu Uchinokura, Etsuyuki Matsu ...
1986Volume 55Issue 11 Pages
3903-3917
Published: November 15, 1986
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Successive phase transitions of K
2ZnCl
4 have been studied by Raman scattering. The critical behaviour of the normal-incommensurate phase transition was discussed on the basis of the temperature dependence of the amplitude-mode frequency and the intensity ratio of this mode to the 49 cm
−1 peak. It does not agree with the mean-field theory. At low temperatures this frequency is affected by the low-temperature phase transition. With respect to the low-temperature phase transition, a new soft mode was found in addition to a totally symmetric soft mode. Polarization characteristics of these soft modes show that the low-temperature phase has
Cs4 symmetry. The temperature dependence of these soft-mode frequencies indicates that the transition temperature is 155 K. A Landau theory was applied to calculate the frequencies of the amplitude mode and the two soft modes.
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Hirofumi Sakashita, Hikaru Terauchi, Naomi Tanba, Yoshihiro Ishibashi
1986Volume 55Issue 11 Pages
3918-3923
Published: November 15, 1986
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The successive phase transitions in BaZnGeO
4 have been examined by the X-ray diffraction method in the temperature range from 300 to 135 K. Especially, the temperature dependence of the satellite peak position δ along the
c-axis is determined. It is found that δ is nearly equal to (1/4)c
* in the incommensurate phase III and is exactly (1/4)c
* in the ferroelectric phase III′. It becomes also evident that the phase IV is the incommensurate phase, where δ varies from 0.25 c
* to about 0.26 c
* continuously, while this phase has been believed to be the commensurate phase with the modulation (1/3)c
*.
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Yutaka Kaneko, Akira Ueda
1986Volume 55Issue 11 Pages
3924-3930
Published: November 15, 1986
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The diffusive motion of cations in the model system of α-AgI is studied with use of a molecular dynamics(MD) method. The static and dynamic correlations among cations and anions are analysed by the following three approaches. First the correlation between the diffusing cations and the tetrahedron(TH) of the anion bcc sublattice is examined. The potential energy experienced by cations which move from one TH to its nearest neighbor TH is calculated. It is found that the main driving force responsible for diffusion is the Coulomb force. Secondly the space- and time correlation functions are investigated. Finally we have produced the 16 mm movie from the MD data in order to observe the ionic motion directly. Strongly correlated motions between cations and anions are clearly observed.
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Yukiyasu Ozeki, Takuma Ishikawa
1986Volume 55Issue 11 Pages
3931-3940
Published: November 15, 1986
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The ac ionic conductivity is calculated for a binary systems consisting of two kinds of ions in the square lattice by the path probability method. It is shown that the percolation efficiency introduced by Suzuki, Sato and Kikuchi can be generalized to case of the frequency dependent conductivity, and it approaches unity at the high frequency limit.
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Takeshi Kodama, Yukio Osaka
1986Volume 55Issue 11 Pages
3941-3947
Published: November 15, 1986
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We report the calculation of the binding energy
EB of a screened hydrogen impurity placed at center of quantum well wire with a square cross-section of the length
L, which is surrounded by an infinite barrier. The random-phase-approximation static dielectric function at zero temperature and electric quantum limit are adopted. For the case that
L is comparable to
aB (
aB is the effective Bohr radius of hydrogenic impurity in bulk), it is shown that
EB is minimum near
aBkF=0.5 (
kF is the Fermi wave number) and the screening effect of mobile carriers on
EB is neglected for the case
aBkF>>1.
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Makoto Matsumoto, Shinya Wakoh
1986Volume 55Issue 11 Pages
3948-3959
Published: November 15, 1986
Released on J-STAGE: June 01, 2007
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Two-dimensional angular correlations of positron annihilation radiation in vanadium and chromium are calculated by the APW method. The results are compared with recent experimental data. The agreement between theory and experiment is very good. Some knowledge of positron-electron many-body correlations is obtained. The sp-like components are enhanced by many-body effect more than the d-like component, and the enhancement appears to be anisotropic in 3d transition metals.
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Daijiro Yoshioka
1986Volume 55Issue 11 Pages
3960-3968
Published: November 15, 1986
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Two component, or pseudospin 1/2, fermion system in the lowest Landau level is investigated. The ground state at ν=2⁄5, where ν is the filling factor of the lowest Landau level, has quite different character from that of ν=1⁄3: In the former the total pseudospin is zero, while in the latter pseudospin is fully polarized. The excitation spectrum from these qualitatively different ground states are investigated numerically at small but finite momentum. The quasiparticles for these ground states are also investigated, and existence of those with charge ±
e⁄5 at ν=2⁄5 is shown. The knowledge of the quasiparticle charge makes extrapolation of the numerical results to infinite momentum possible, and activation energies are obtained.
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Yoshiyuki Ono, Yasushi Ohfuti
1986Volume 55Issue 11 Pages
3969-3977
Published: November 15, 1986
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The ground states of nearly quarter-filled one-dimensional electron-phonon systems are numerically investigated by using Su-Schrieffer-Heeger’s model and a Fröhlich-type model. When the electron filling factor is very near to but different from 1/4, the ground state is the soliton lattice. The structure factors of the CDW’s in the soliton lattice states are calculated and their square moduli are found to have several peaks, the main one corresponding to the 2
kF mode and others being explained as its higher harmonics. The behaviour of the higher harmonics as functions of the filling factor and the electron-phonon coupling constant is studied and the model dependence is discussed. The distribution of the field gradient at off-chain sites due to the CDW is considered in connection with the quadrupole shift of the recent NMR measurement in Rb
0.3MoO
3.
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Yasumasa Hasegawa, Hidetoshi Fukuyama
1986Volume 55Issue 11 Pages
3978-3990
Published: November 15, 1986
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Phase transitions in quasi-one-dimensional electron systems with imperfectly nested Fermi surface have been investigated. The spin-density-wave (SDW) transition temperature is obtained as a function of the degree of imperfect nesting of the Fermi surface. The wave vector of SDW at the transition temperature is shown to change discontinuously at a critical value of the degree of imperfect nesting. The competition between SDW and various types of superconductivity is also discussed. It is shown that there are no coexistent state in Ginzburg-Landau region. The application to the organic conductors, (TMTSF)
2X, is discussed.
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Ichiya Sadakata
1986Volume 55Issue 11 Pages
3991-3994
Published: November 15, 1986
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The theory of the conductivity for strongly disordered systems [J. Phys. Soc. Jpn.
54 (1985) 736] is applied to the Anderson model. It is shown that the metal-insulator transition occurs at the reasonable value of the strength of disorder.
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Shigenori Hayashi, Shigeaki Nakajima, Keiichi Kaneto, Katsumi Yoshino
1986Volume 55Issue 11 Pages
3995-4002
Published: November 15, 1986
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The electrochemical and magnetic properties of polyazulene have been studied by electrochemical cyclic voltammetry and ESR. Two pairs of oxidation and reduction peaks have been observed in the cyclic voltammogram which indicates that reversible p-type doping. The anomalous behavior of the spin susceptibility χ upon electrochemical doping, associated with these redox peaks in the cyclic voltammogram, has been revealed by the
in situ measurement; the extraordinary large χ=
ca. 4×10
−5 emu/mol in the neutral state once decreases upon doping to 2×10
−5 emu/mol at several mol% and then increases up to
ca. 7×10
−5 emu/mol corresponding to the as-grown state at
ca. 25 mol%, and then decreases again at higher doping levels. These results can be interpreted as two-stages doping (oxidation) process into polyazulene with a unique band structure.
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Takaharu Abe
1986Volume 55Issue 11 Pages
4003-4006
Published: November 15, 1986
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Using the molecular field theory, the paramagnetic susceptibility of ferromagnetic rare earth-transition metal compounds is investigated. When the itinerant electron’s susceptibility χ
c obeys the C–W (Curie–Weiss) law, the total susceptibility χ obeys an approximate C–W law at sufficiently high temperatures and, if the
s-
f exchange integral
J is negative, the Curie point
Tc is higher than the paramagnetic Curie point
Θp. However, the relation between the induced spin polarization coefficient α and 1⁄χ vs
T curve is intricate. This prediction is confirmed by experiments on the susceptibility of GdNi
3 (
Tc=113 K) in the temperature range from 113 K to 700 K. Above around 340 K χ obeys an approximate C–W law with
Θp=70 K and
peff=7.99 which is the effective Bohr magneton number. The exchange integral
J is negative and the value of α at
Tc is roughly estimated to be −0.08.
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Nobuyuki Momozawa
1986Volume 55Issue 11 Pages
4007-4013
Published: November 15, 1986
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Neutron diffraction experiments were carried out on a single crystal of (Ba
1−xSr
x)
2Zn
2Fe
12O
22,
x=0.748, at 77 and 296 K. The turn angle of the helix, φ
0, is 81.6° at 77 K and 135° at 296 K. The helix consists of large and small ferrimagnetic spin-bunches separated by an angle of φ
0⁄2 in the
c-plane. Their magnitudes are 4.32 μ and 0.32 μ, respectively. Here, μ is the magnetic moment per Fe ion: μ=4.66 μ
B at 77 K and μ=1.86 μ
B at 296 K. These results are discussed from a point of view of the super-exchange interaction.
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Fumihisa Ono, Yukihiro Ohtsu, Osamu Yamada
1986Volume 55Issue 11 Pages
4014-4019
Published: November 15, 1986
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A simple method has been established for a determination of the magnetic anisotropy constants from an unsaturated torque curve. In this method a least mean square routine was adopted instead of the usual Fourier analysis which has been widely used by many authors. The method has been applied to the recently developed high energy permanent magnet, Nd
2Fe
14B, of which torque curves were not saturated by using an ordinary electromagnet. The validity of the present method has been checked by applying it to the case of hcp Co for which the saturated values were known.
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Y\={u}ichi Tazuke, Shin-ichi Kinouchi, Hidekazu Tanaka, Katsunori Iio, ...
1986Volume 55Issue 11 Pages
4020-4024
Published: November 15, 1986
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Magnetic susceptibility study is made in 4.2 K≤
T≤350 K on single crystals of a Heisenberg antiferromagnet RbCuCl
3, which shows two crystallographic phase transitions at
Tc1=339 K and
Tc2=260 K. Its susceptibility shows a discontinuous jump at
Tc2 and a continuous temperature variation around
Tc1. At 19 K it shows a cusp, which suggests an antiferromagnetic phase transition. The data below
Tc1 are analyzed by the high temperature expansion approximation, and intrachain and interchain exchange interactions (
J0 and
J1) are determined. The results are:
J0⁄
k=(−20±2) K and
J1⁄
J0=−0.20±0.02 below
Tc2, and (
J0+3
J1)⁄
k=2.6 K above
Tc2.
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Tomiei Hori, Yasuaki Nakagawa
1986Volume 55Issue 11 Pages
4025-4029
Published: November 15, 1986
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MnHg
1−xAu
x(
x≤0.25) has a CsCl-type structure with the lattice parameter
a=3.28 Å for
x=0.25 at room temperature. The magnetic susceptibility exhibits an anomaly at about 180 K, where the lattice is distorted to an orthorhombic structure Pmma with
a=4.71,
b=3.08 and
c=4.81 Å at 88 K. Eight nearest neighbors of each atom prove to be almost equidistant even after the distortion.
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