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Shunji Kawamoto
1984 Volume 53 Issue 2 Pages
469-471
Published: February 15, 1984
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Exact explode-decay mode solitary wave solutions of the one-dimensional classical Boussinesq and Burgers’ equations are obtained through the similarity variables. These solutions are expressed by the Gauss error functions, and have no divergent backgrounds. Also, it is shown that the two equations can be reduced to the Kummer, Whittaker’s, modified Bessel’s, Hermite’s, or Weber’s equation.
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Mitsuru Yamagiwa, Toshinori Michishita, Hiroshi Nishihara
1984 Volume 53 Issue 2 Pages
472-475
Published: February 15, 1984
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Current drive by applying lower hybrid wave is numerically investigated by using a one dimensional tokamak transport code in order to study effect of changes in plasma profiles on the efficiency of current drive. The efficiency is compared among small, medium, and large tokamaks. It is found that the deposition of wave power moves outwardly due to the increase in the local electron temperature. The efficiency depends on the scale of tokamak. For particularly large tokamak, the average efficiency increases with the width of resonance region in the velocity space of electrons, and reaches up to 1 MA/10 MW.
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Satoshi Tanda, Takashi Sambongi, Toshiro Tani, Shoji Tanaka
1984 Volume 53 Issue 2 Pages
476-479
Published: February 15, 1984
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Positions of satellite reflections in charge density wave (CDW) phases of 1T-TaS
2 were measured by X-ray diffraction. In the commensurate (C-) phase, stacking of CDW layers is considerably disordered. On heating from the C-phase there appears a new incommensurate triclinic structure up to 280 K, where anomalies have been observed in various properties.
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Masayuki Tokita, Ryoya Niki, Kunio Hikichi
1984 Volume 53 Issue 2 Pages
480-482
Published: February 15, 1984
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Dynamic shear modulus of casein gel was measured slightly above the gelation concentration as functions of frequency and concentration. The results show that the shear modulus
G is expressed by
G=
C·ε
t, where ε is the reduced concentration in reference to the gelation concentration. The exponent
t is found to be constant at lower frequency region and is close to the value expected from the percolation theory.
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Hikaru Terauchi, Takafusa Futamura, Yasuo Nishihata, Satoshi Iida
1984 Volume 53 Issue 2 Pages
483-486
Published: February 15, 1984
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X-ray study on a random mixture of a ferroelectric and an antiferroelectric, Rb
1−x(NH
4)
xH
2PO
4, has been carried out. The glassy phase (dipole-glass phase) is found to be tetragonal, although the deviation of a lattice parameter from the Debye approximation is seen at low temperatures. The intensity of the X-ray diffuse scattering increases with decreasing temperature in the glassy phase. The results suggest a freezing of the short range order or the local polarization in the glassy phase.
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Youji Okazaki, Keigo Nagasaka
1984 Volume 53 Issue 2 Pages
487-490
Published: February 15, 1984
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Photoconductivity spectra of floating-zone Si(P) samples with densities of dislocations 10
4 or 10
6–10
7 cm
−2 have been measured in the range from 250 to 400 cm
−1 in order to explore shallow dislocation levels. New lines are observed in the annealed Si(P) samples with cutting damage surface. However, these are insensitive to dislocation density, and strongly influenced by the surface condition in the annealing operation. Thus these new lines are to be ascribed to complex centers: a P atom paired with another kind of impurity or point defect which is introduced from cutting damage surface and diffused into the bulk.
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Keizo Murata, Hiroyuki Anzai, Takashi Ukachi, Takehiko Ishiguro
1984 Volume 53 Issue 2 Pages
491-494
Published: February 15, 1984
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The pressure-temperature phase diagram of bis-tetramethyltetrathiafulvalenetetrafluoroborate, (TMTTF)
2BF
4, is determined through the electrical conductivity measurement along the
a-axis. Two distinct metal-insulator transitions are observed at
T1=200 K (
P<5 kbar) and at
T2=
ca. 50 K (
P>5 kbar). We conjecture that the
T1 transition is associated with an anion-orientational ordering, while
T2 is with the spin-Peierls ordering. The large difference in the transition temperatures for the resistivity at 200 K and for both the magnetic susceptibility and the specific heat at 41 K in the early reports is reconciled by taking account of the two types of transitions.
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Yukimichi Tajima, Kazuhiko Yamaya
1984 Volume 53 Issue 2 Pages
495-498
Published: February 15, 1984
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A giant resistivity which depended on the current density,
J, was observed within the superconducting transition region of TaSe
3 by measuring the dc resistivity at extremely low
J. It is suggested that the giant resistivity has close relations with the superconducting phase itself rather than other phases such as charge-density-waves or spin-density-waves.
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Hidenori Kubo, Norikiyo Uryû
1984 Volume 53 Issue 2 Pages
499-502
Published: February 15, 1984
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To clarify the spin structure in oblique antiferromagnetic (OAF) phase, proton NMR measurements are carried out at 1.7 K in zero applied field. The OAF phase is found in the region of 2.5%\lesssim
x\lesssim11%, from the concentration dependence of NMR spectra. The spectra are interpreted by the model that in OAF phase, the moments surrounding Co impurity are drawn towards the impurity and then directed to other directions. Simultaneous tilting of all moments is denied by a little shift of the main line.
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Kazuyoshi Yoshimura, Tadashi Shimizu, Masashi Takigawa, Hiroshi Yasuok ...
1984 Volume 53 Issue 2 Pages
503-506
Published: February 15, 1984
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The Knight shift,
K, and the nuclear spin-lattice relaxation time,
T1, of
59Co have been measured in an exchange-enhanced Pauli paramagnet YCo
2. 1⁄(
T1T)
d has been found to be proportional to χ
d, which is in good accord with the prediction from the self-consistent renormalization (SCR) theory of spin fluctuations in weakly or nearly ferromagnetic metals.
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Toru Shimizu
1984 Volume 53 Issue 2 Pages
507-514
Published: February 15, 1984
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Using the Wadati Transformation which connects inverse scattering schemes of isotropic Heisenberg equation and a new integrable nonlinear evolution equation,
N-soliton solution of isotropic Heisenberg equation is obtained. The relation between soliton solutions of both equations is also clarified.
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Kaoru Yasumura, Takehiko Oguchi
1984 Volume 53 Issue 2 Pages
515-521
Published: February 15, 1984
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High temperature series expansions of the staggered susceptibility of the
q-state antiferromagnetic Potts model (AFPM) on a
d-dimensional hypercubic lattice are calculated. For arbitrary values of
q and
d, the transition temperatures and the critical exponents γ are determined by use of the ratio method and the Padé approximation. It is shown that the 3- and 4-state AFPM exhibit a second-order phase transition when
d≥3, and the 5- and 6-state AFPM do when
d≥4, etc. In the limit of infinite
d, the transition temperature
Tc is obtained rigorously as
kTc⁄
J={log [2
d⁄(2
d−
q)]}
−1 (
k: the Boltzmann constant,
J: the interaction parameter), and the ordered phase exists when
d>
q⁄2.
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Kunisuke Nisizima, Kazuyosi Ikeda
1984 Volume 53 Issue 2 Pages
522-532
Published: February 15, 1984
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The exact expressions for the
volume-dependent cluster sums (composed of four or less molecules) for the two-dimensional square lattice gas (in a square-shaped vessel) with nearest and second nearest neighbour interactions are obtained. The method used consists of the calculation of the exact partition functions and the calculation of the cluster sums from them with the use of the inverse relation. The detailed behaviour of the cluster sums as functions of the volume is investigated for the case when the nearest neighbour interaction is repulsive and the second nearest neighbour interaction is attractive. Finally a remark is given on the condensation of such a lattice gas.
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K. Singh, H. S. Sahota
1984 Volume 53 Issue 2 Pages
533-537
Published: February 15, 1984
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Precisely calibrated high resolution intrinsic semiconductor detector has been used to find
K-capture probabilities to 400.56 and 279.48 keV levels in the decay of
75Se. The measurement to 279.48 keV level is reported for the first time in literature.
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Susumu Ohya, Osamu Nakamura, Katsuhiko Nishimura, Akira Furusawa, Naos ...
1984 Volume 53 Issue 2 Pages
538-542
Published: February 15, 1984
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The decay of
56Co to the levels of
56Fe has been investigated using low-temperature nuclear orientation in the hyperfine magnetic field in iron. Based on the anisotropies of the γ rays, the following spin assignments are established: 4
+ (4100.2- and 4298.0-keV levels) and 3
+ (4119.8- and 4395.0-keV levels). Multipole mixing ratios of a number of γ transitions are reported. In addition, upper limits of the Fermi to Gamow-Teller matrix element ratios of the two 4
+–4
+ electron capture and β
+ transitions to the 4100.2- and 4289.0-keV levels are obtained.
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Takahiro Tachibana
1984 Volume 53 Issue 2 Pages
543-553
Published: February 15, 1984
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A semi-empirical method of estimating the β-strength function from data on three neighbouring nuclides, which was originally devised for a special class of nuclei, is applied to a wider class of odd-mass nuclei. When good experimental data are available on the neighbouring nuclides, the estimated β-strength functions generally reproduce the trend of experimental ones fairly well, although a serious discrepancy is found for
49Ca suggesting the inadequacy of this method near the doubly closed shell. Delayed neutron emission probabilities are calculated with use of the estimated β-strength functions. An agreement with experiment within a factor of two is obtained provided that the β-strength function is based on good input data on the neighbouring nuclides.
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Junichi Yoshida, Kiyosi O-Ohata
1984 Volume 53 Issue 2 Pages
554-562
Published: February 15, 1984
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The potential curves and the non-adiabatic coupling matrix elements for the Li
++He collision system were computed. The SCF molecular orbitals were constructed with the CGTO atomic bases centered on each nucleus and the center of mass of two nuclei. The SCF and CI calculations were done at various internuclear distances in the range of 0.1∼25.0 a.u. The potential energies and the wavefunctions were calculated with good approximation over whole internuclear distance. The non-adiabatic coupling matrix elements were calculated with the tentative method in which the ETF are approximately taken into account.
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Yukinori Sato, Masato Kikuchi, Hokotomo Inouye
1984 Volume 53 Issue 2 Pages
563-566
Published: February 15, 1984
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Energy-loss spectra of H
+, He
+ and H
2+ ions scattered by acetylene (C
2H
2) molecules have been studied in the collision energies between 1 and 2.5 keV at a scattering angle of 0°C. It was observed that, in accordance with the Wigner spin rule, the H
+-impact on acetylene induced only the singlet-singlet (S–S) transitions of acetylene while the He
+-impact and the H
2+-impact induced both the S–S and the singlet-triplet (S–T) transitions of acetylene. A difference was found between the He
+-impact and the H
2+-impact excitation of the S–T transitions of acetylene in that the lowest-lying triplet state \ ilde
a 3Σu+ was preferentially excited by the He
+-impact but both the lowest and second lowest triplet states, the \ ilde
a and the \ ilde
b 3Δu, were excited by the H
2+-impact.
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Tetsuo Koizumi, Kazuhiko Okuno, Yozaburo Kaneko
1984 Volume 53 Issue 2 Pages
567-573
Published: February 15, 1984
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An injected-ion drift tube mass spectrometer was used to study the one-electron capture reactions in the systems Kr
+++Ne and Xe
+++Ar. The drift tube was cooled with liquid nitrogen so as to widen the energy range from 10 meV to several eV. The cross sections for the ground state of primary ions were separated from those for the low-lying metastable states by applying both the attenuation method and the threshold measurement. It was found that a large difference exists in the absolute magnitudes or cross section according to the electronic states of primary ions. The reaction Xe
++(
3P)+Ar has a very large cross section of 10
−14 cm
2 at 0.02 eV, while the reaction Xe
++(excited)+Ar is immeasurable. This difference is explained with a curve crossing model.
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Takashi Fujimoto, Chiaki Goto, Kuniya Fukuda
1984 Volume 53 Issue 2 Pages
574-581
Published: February 15, 1984
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The observed decay of a fluorescence intensity following a pulsed laser excitation is, in general, different from the decay of the upper-level population. By using the magic-angle excitation and a magnetic field this difficulty has been resolved. The pressure dependence of the decay rate has been measured for neon 2
p53
p levels, and the collisional depopulation rate coefficient has been derived. The conjecture by Chang and Setser (J. Chem. Phys.
72 (1980) 4099) that the dominant depopulation from some of the levels is attributed to deexcitation 2
p53
p→2
p53
s has been shown incorrect.
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Hiroyuki Ito
1984 Volume 53 Issue 2 Pages
582-584
Published: February 15, 1984
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The analogy between the theory of a self-avoiding chain and the Lagrangian field theory is derived directly and simply by means of a continuous matrix, without use of the perturbation expansions and the diagram methods.
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R. C. Gupta
1984 Volume 53 Issue 2 Pages
585-591
Published: February 15, 1984
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The procedure of Fargie and Martin which employs both the differential and integral momentum equations has been extended to study the developing laminar flow behaviour of Power-law fluids in a straight channel. Simple closed form expressions for the boundary layer development and the inlet region pressure distribution have been obtained. Results have been illustrated graphically and compared with another theoretical solution.
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Hiromichi Ezumi, Masahiko Kawamura, Noriaki Gohda
1984 Volume 53 Issue 2 Pages
592-600
Published: February 15, 1984
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The Ionization relaxation and radiative-cooling processes behind shock wave in xenon with or without a small amount of hydrogen have been investigated using a quadrature interferometer technique at shock Mach numbers
Ms∼13 and the initial pressure
P1=2.0 Torr. By adding a small amount of hydrogen (∼0.5% of the initial pressure) to xenon, the ionization relaxation time was drastically reduced to about one-third of its pure xenon value. From the comparison between theoretical values based on the two-step ionization model and experimental data, the slope constants of excitational cross-section against relative kinetic energy between xenon atom-atom collisions and xenon-hydrogen atom-atom collisions were determined to be 1.8×10
−19 cm
2/eV and 9.0×10
−19 cm
2/eV, respectively.
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Kenji Harafuji, Hiroshige Watanabe, Shigeo Nagao
1984 Volume 53 Issue 2 Pages
601-612
Published: February 15, 1984
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Four types of particle motions, namely, passing particle, blocked particle, untrapped banana and trapped banana are studied on the basis of analytical and computational methods in the drift approximation in a helical solenoid with low toroidicity. Computational results for trapped particles are in good agreement with those of theoretical predictions, when magnetic field configuration has a good helical symmetry, that is, α
r0∼1.0 and
n>>1, where 2π⁄α and
r0 are the pitch and the radius of helical magnetic axis, respectively, and
n is the pitch number of the system. In this case, the action is well conserved, especially for the trapped banana with small excursion along the axial direction.
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Satoshi Higaki, Hirokazu Fujita, Shuji Miyamoto, Kazuo Imasaki, Sadao ...
1984 Volume 53 Issue 2 Pages
613-619
Published: February 15, 1984
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The plasma jet formation experiments on cylindrical Au target applying a focused REB generated by REIDEN III were performed. The clear evidence of jet formation was shown by N
2 laser shadowgrams and damages remained on the target holders. The velocity and the energy density enhancement in jet was observed. In the conical cavity target irradiation, the areal mass density of the foil was increased as the results of the areal plasma convergence in the cavity.
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Toyonori Munakata, Akito Igarashi
1984 Volume 53 Issue 2 Pages
620-626
Published: February 15, 1984
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Thermal expansion of a one-dimensional anharmonic lattice is studied from a dynamical point of view. Our averaged-Lagrangian scheme gives an expression for a local strain operator in terms of the fundamental modulation ψ
±1, time evolution of which is governed by a nonlinear Schroedinger (NLS) equation. Regarding the expansion produced by the NLS soliton (a one-soliton solution to the NLS eq.) as a unit of lattice expansion, we calculate the contribution to thermal expansion from self-modulation of monochromatic waves and compare it with the exact result.
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Kazuo Gesi, Kunio Ozawa
1984 Volume 53 Issue 2 Pages
627-634
Published: February 15, 1984
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The pressure-temperature phase diagram of tetramethylammonium tetrachloromanganate {N(CH
3)
4}
2MnCl
4 was determined by dielectric measurements. As pressure increases the normal phase (I) to incommensurate phase (II) transition temperature (19.7°C at 0 MPa) increases. The region of commensurate phase with
c=2
c0 (III) becomes narrower with increasing pressure and disappears at about 125 MPa. A peak of dielectric constant along the
a-direction is observed in a pressure range from 135 MPa to 240 MPa in the incommensurate II phase. The peak value decreases with increasing pressure. Above about 275 MPa the normal phase I directly transforms to the lowest temperature phase V (stable below −101°C on cooling at 0 MPa). The compound {N(CH
3)
4}
2MnCl
4 does not show ferroelectricity at high pressure unlike to the compounds of {N(CH
3)
4}
2ZnCl
4, {N(CH
3)
4}
2CoCl
4, and {N(CH
3)
4}
2FeCl
4.
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Ichiro Hatta
1984 Volume 53 Issue 2 Pages
635-642
Published: February 15, 1984
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Two coupling terms between the order parameter
Q(
q) with wave vector
q and strain ε
i, (a) γ
i(
q)
Q(
q)
Q(−
q)ε
i and (b) η
i(
q)
Q(
q)
Q(−
q)ε
i2, give rise to the anomalous behavior of the elastic stiffness at the phase transition. The coupling (b) causes a similar critical stiffness constant in both longitudinal and transverse waves. On the other hand, (a) brings about the softening of the stiffness constant only in longitudinal waves. Using these characteristics the anomaly caused through (a) is isolated under a minimum assumption and then, γ
i(
q) for i=1–3 are estimated. Contrary to a simple theoretical prediction, the above anomaly is not proportional to that of the specific heat. It is partly due to the disregard of the
q-dependence of γ
i(
q). This effect should be taken into account in the study of the elastic anomaly in the other substances.
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Kyûya Baba
1984 Volume 53 Issue 2 Pages
643-652
Published: February 15, 1984
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Using a simple model with
fd-hybridization process and electron-phonon interaction, we investigate the polaron effects on the
f-level width in mixed-valent systems of rare-earth materials at finite temperatures and find that strong polaron effects must show significant temperature dependences to diminish at temperatures higher than the characteristic phonon energy and an explicit account of the conservation of electron number makes such temperature dependences more significant. We also discuss several possibilities to observe such temperature dependences in experiments.
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Masahiko Morinaga, Natsuo Yukawa, Hirohiko Adachi
1984 Volume 53 Issue 2 Pages
653-663
Published: February 15, 1984
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The influence of a number of alloying transition elements on the electronic structure of Ni
3Al (γ′) has been studied by the DV–Xα cluster method. The
d orbital levels of the alloying elements appear above the Fermi level, and these change monotonously with atomic number, electronegativity and metallic radius of the element. These level structures associated with
d electrons characterize the alloying elements as whether they are elements partitioning to γ phase, to γ′ phase or to grainboundary. The substitution of alloying elements for either Ni or Al site was also discussed in terms of electronic structure. Further, the ionicity of each element, and the bond order between elements in γ′ phase have been calculated, which provide basic informations for understanding bond nature in the alloy. These informations were found to be useful for developing better nickel base superalloys with a high performance at elevated temperatures.
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Katsunori Mori, Yosikazu Isikawa, Kiyoo Sato
1984 Volume 53 Issue 2 Pages
664-666
Published: February 15, 1984
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The thermal conductivity and the electrical resistivity of polycrystalline ErNi which is ferromagnetic below 10 K have been measured as a function of temperature between 1.5 and 15 K. The Lorenz function, calculated from the measured thermal conductivity and electrical resistivity values on the same sample, exceeded the value expected for electron heat conduction. This indicates that magnons significantly contribute to the heat conduction. The electrical resistivity below 3 K was proportional to
T1.9±0.3 which is due to spin-disorder resistivity.
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Shin-ichi Uchida, Shoji Tanaka
1984 Volume 53 Issue 2 Pages
667-675
Published: February 15, 1984
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The electron localization in 1T-TaS
2 is studied by means of the analysis of the non-Ohmic conduction which is observable below liquid N
2 temperature. By correlating the electric field dependences of the conductivity, Hall coefficient and magnetoresistance with their temperature dependences it is found that an electric field has the effect of raising an electron temperature (hot-electron effect). The non-Ohmic conduction due to the electron heating mechanism is highly suggestive for the existence of the weakly localized states. The inelastic scattering length which determines the rise of the electron temperature is estimated. It shows the temperature dependence proportional to
T−1⁄2 above 15 K, whereas it is almost
T-independent below 15 K. This may possibly be interpreted as a gradual change of the mechanism of the non-Ohmic conduction associated with a crossover towards stronger localization as the temperature is lowered.
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Sigeru Takayanagi
1984 Volume 53 Issue 2 Pages
676-681
Published: February 15, 1984
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The electrical resistivity of singlet-ground-state compounds of praseodymium, PrCu
5 and PrCu
6, has been measured at temperatures between 1.5 K and 300 K. The experimental results showed the effects of crystalline-electric-field splitting of the 4
f state of Pr ions. In PrCu
5, it was found from a comparison with theory that the aspherical Coulomb-charge scattering of conduction electrons by Pr ions makes an important contribution to the resistivity.
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Toshiaki Nambu, Shinji Kawaji, Keiju Kuboki, Yoichi Kawaguchi, Junji Y ...
1984 Volume 53 Issue 2 Pages
682-686
Published: February 15, 1984
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Angular dependence and temperature dependence of negative magnetoresistance in two-dimensional electron gas in GaAs/Al
xGa
1−xAs (
x\simeq0.3) heterostructure are measured at temperatures between 4.2 K and 1.1 K. The temperature dependence of τ
ε is analysed by a theory developed recently by Fukuyama and Abrahams. The experimental τ
ε−1 in the dirty limit is smaller than the theoretical one by a factor of 1.5∼2.3.
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Yuji Takakuwa, Shoji Suzuki, Tatsuo Yokotsuka, Takasi Sagawa
1984 Volume 53 Issue 2 Pages
687-695
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Angle-resolved UPS spectra of 4f levels of Yb metal measured as a function of electron take-off angles have given a direct confirmation that satellite peaks of the 4f levels are due to the surface Yb atoms. Upon oxygen exposure, these surface components of the 4f levels do not show any preferential reduction in intensity and the work function decreases. These suggest the diffusion of adsorbed oxygen atoms underneath the Yb surface. By a mass analysis with hydrogen exposure to the Yb surface, it has been found that the surface is hydrogen free even though the evaporated Yb film contains hydrogen in the bulk. These facts lead to the interpretation that the surface 4f level shift in Yb metal is not hydrogen-induced but intrinsic.
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Tatsuo Yokotsuka, Shozo Kono, Shoji Suzuki, Takasi Sagawa
1984 Volume 53 Issue 2 Pages
696-701
Published: February 15, 1984
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Angle-resolved ultraviolet photoemission measurements have shown that the surface electronic structure of the Ge(111)7×7-Sn surface is essentially the same as that of the Si(111)7×7 surface. Metallic surface states of the Ge(111)7×7-Sn surface reveal a slight dispersion of an approximate 2×2 periodicity. The so-called dangling- and the back-bond surface states of the Ge(111)“2×8” surface also show a slight dispersion. The dangling- and the back-bond surface states of the Ge(111)7×7-Sn surface lie at nearly the same binding energies as those for the Ge(111)“2×8” surface rather than those for the Si(111)7×7 surface.
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Sadamichi Maekawa, Saburo Takahashi, Masashi Tachiki
1984 Volume 53 Issue 2 Pages
702-711
Published: February 15, 1984
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Effects of tunneling motion of atoms characteristic in glass systems on superconductivity is theoretically studied. The pair-breaking mechanism of superconductivity proportional to [ln (
T⁄
D)]
2 is derived in the fourth order of the Coulomb interaction between conduction electrons and atoms, where
T is the temperature and
D is the band width. We propose that the pair-breaking mechanism is an origin of the universal absence of the Maki term in the paraconductivity in amorphous superconductors.
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Kazushige Machida
1984 Volume 53 Issue 2 Pages
712-720
Published: February 15, 1984
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The interplay between superconductivity and charge density wave state concomitant with the lattice instability is discussed theoretically based on the partial gapping model appropriate for anisotropic materials. The present calculation aims at supplementing the theory by Bilbro and McMillan on the same partical gapping model. Various thermodynamic quantities such as the specific heat jump at the superconducting transition and anisotropic penetration depth easily accessible by experiments are derived.
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Takashi Iwashita, Norikiyo Uryû
1984 Volume 53 Issue 2 Pages
721-728
Published: February 15, 1984
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For the two-dimensional quadratic Ising ferromagnet with mixed spins of
S=1⁄2 and
S=1, the Curie temperature
Tc has been calculated with the use of Bethe-Peierls theory. Assuming the bilinear exchange interactions
J1 between nearest neighbors (n.n.) of the different spins,
J2 and
J3 between two kinds of next nearest neighbors (n.n.n.) of the same spins, and the biquadratic exchange
J1′ between n.n. and
J2′ between n.n.n. of spins
S=1, the behaviors of
Tc as a function of these exchange parameters are investigated. The ferromagnetic order is shown to be unstable when the ratio
J1′⁄
J1 amounts to −1.85. It is also pointed out that
J1′ and
J2′ give a qualitatively different effect on
Tc. Furthermore, it turns out that the exchange interaction
J2 between n.n.n. of spins
S=1 gives more significant effect on
Tc than
J3 between n.n.n. of spins
S=1⁄2.
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Osamu Yamada, Etienne du Tremolet de Lacheisserie
1984 Volume 53 Issue 2 Pages
729-734
Published: February 15, 1984
Released on J-STAGE: May 29, 2007
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The forced volume magnetostriction measured precisely in a relatively weak magnetic field shows a sharp maximum in the region of Curie temperature for a 36.4 at%Ni–Fe Invar alloy.
The magnetovolume coupling constant
C determined in the temperature range between room temperature and the Curie temperature is found to be approximately 1.2×10
−8 cm
6/emu
2 and almost independent of the temperature, under the condition that the forced volume magnetostriction is related with the local magnetic moment and the high-field susceptibility due to the band term.
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Kazuko Motizuki, Keiko Katoh
1984 Volume 53 Issue 2 Pages
735-746
Published: February 15, 1984
Released on J-STAGE: June 01, 2007
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Magnetic properties of the NiAs-type MnAs in paramagnetic and ferromagnetic phases are studied on the basis of the spin fluctuation theory. For use in this calculation we have calculated the electronic bands by the self-consistent APW method. The results for the magnetic susceptibility and magnetic moment are found to be consistent with observations. In particular, the anomalous behavior of the susceptibility in the intermediate phase of the MnP-type structure is explained qualitatively.
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Hiroshi Yamauchi, Hideya Onodera, Hisao Yamamoto
1984 Volume 53 Issue 2 Pages
747-753
Published: February 15, 1984
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The critical behavior of magnetic phase transition in amorphous Fe
92Zr
8 and Fe
90Zr
10 ferromagnets has been studied by static magnetization measurement. The magnetization data taken in the critical region yield the following values for the critical exponents, respectively: β=0.620±0.003, γ=1.92±0.02, δ=5.82±0.06 for Fe
92Zr
8; and β=0.560±0.003, γ=1.87±0.02, δ=4.84±0.06 for Fe
90Zr
10. These values deviate substantially from those derived for a three dimmensional homogeneous Heisenberg ferromagnet. The results, together with other anomalous magnetic phenomena, have been discussed as originating from an extremely wide distribution of exchange integrals. In particular, it has been suggested that the spin-glass like behavior can be ascribed to the thermally activated magnetization process of the cluster-spin glass.
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Hiroyuki Sasakura, Katsuhiko Suzuki, Yoshika Masuda
1984 Volume 53 Issue 2 Pages
754-759
Published: February 15, 1984
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The magnetization of the itinerant electron ferromagnetic Ni
3Al system has been measured. The experimental result of temperature dependence of the spontaneous magnetization agrees with the prediction of the self-consistent renormalization (SCR) theory of spin fluctuations. Considering the variations of the band structures with the Ni-concentration
x by alloying, the experimental result of the
x-dependence of the Curie temperature
Tc is also explained within the framework of the SCR theory.
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Midori Tanaka, Kiiti Siratori, Noboru Kimizuka
1984 Volume 53 Issue 2 Pages
760-772
Published: February 15, 1984
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Mössbauer spectra of RFe
2O
4 (R=Y, Ho, Er, Tm or Yb) were measured between 200 and 500 K, in the paramagnetic region. Amalgamation, from two quadrupole doublets due to different ionic states of Fe into one doublet, was observed and successfully analysed by a stochastic theory, except the stoichiometric Y and Er compound. In the latter case, in which Verwey transition takes place at low temperature, the analysis failed because of the existence of other set of absorptions. When the stochastic theory was applicable, seven parameters were deduced at each temperature: isomer shift, quadrupole splitting and width for both states of Fe and the frequency of the fluctuation. It is concluded that Fe atoms fluctuate between two ionic states, neither 2+ nor 3+ in its literal meaning but mixtures of them: itinerant model is more appropriate than the ionic model for 3d electrons of iron in these oxides.
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Yuzo Tomono, Takeshi Kato, Yoshiko Tanokura
1984 Volume 53 Issue 2 Pages
773-779
Published: February 15, 1984
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EPR was studied on KNi
xZn
1−xF
3 crystals, where concentration
x is less than 0.1. Spectrum from single Ni
2+ ions was identified by
g=2.27, and was superposed by superhyperfine structure from surrounding F
− nuclear spins only for the most dilute specimen with
x=0.39%. The other line at 8560 gauss observed with K-band microwave was attributed to isolated Ni
2+ pairs, from the temperature dependence of the intensity. Pair spectra were observed for dilute specimens, and exchange integral
J=83 cm
−1 was deduced from the temperature dependence of the intensity. In addition, complex superhyperfine structure was observed, and its tentative interpretation was given.
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Yoh Kohori, Yoshio Kitaoka, Ken-ichi Kumagai, Kunisuke Asayama
1984 Volume 53 Issue 2 Pages
780-785
Published: February 15, 1984
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Pulsed NMR study has been performed in RERh
4B
4 (RE=rare earth). We obtained the conduction electron spin polarization at B site from the isotropic Knight shift of
11B. The isotropic shift is proportional to (
gJ−1)⁄
gJ, which means
JsfNs(
EF) is nearly same for all RERh
4B
4 compounds. The nuclear spin lattice relaxation time,
T1 of
89Y and
103Rh were measured in YRh
4B
4 and LuRh
4B
4. The density of state at the Fermi level in each atomic site is evaluated from
T1. The agreement of the results with the recent band calculation is satisfactory. The isotropic shift of
103Rh is measured in SmRh
4B
4.
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Kei-ichi Koga, Masatsugu Suzuki
1984 Volume 53 Issue 2 Pages
786-794
Published: February 15, 1984
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The second-stage MnCl
2-graphite intercalation compound (GIC) is a two-dimensional (2D) antiferromagnet with uniaxial anisotropy on the triangular lattice. It undergoes two magnetic phase transitions at
Tc1 and
Tcu (
Tc1=1.1 K and
Tcu=46.7 K). The electron spin resonance of this compound have been measured at 9.43 GHz over the temperature range 4.2 K≤
T≤300 K. The angular dependence or the line-width is or the (3 cos
2θ−1)
2-like form at 300 K (θ is the angle between the external field
H and the
c-axis), indicating the 2D character of this compound. The line-width at θ=90° (
H⊥
c) increases monotonously with decreasing temperature in the temperature range
Tc1≤
T≤
Tcu, while the line-width at θ=0° (
H⁄⁄
c) shows a local minimum between
Tc1 and
Tcu.
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Ko Sugihara, Keiko Matsubara, Takuro Tsuzuku
1984 Volume 53 Issue 2 Pages
795-801
Published: February 15, 1984
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Based on Blinowski-Rigaux’s band model, an expression for the
g-shift (
Δg) in stage-4 donor graphite intercalation compound has been derived by using the Dresselhaus-Dresselhaus spin-orbit Hamiltonian. If the bands are labeled as B
−, A
−, B
+ and A
+ in order of energy
Es,
g-shifts for A
±- and B
±-states are of opposite sign to each other, and in most cases |
Δg(A
−)|>|
Δg(B
−)|>|
Δg(B
+)|>|
Δg(A
+)|. Since the higher the energy
Es the less the state density, the total
g-shift
Δg=Σ
sΣ
EsΔg(
Es)δ(
Es−
EF)⁄Σ
sΣ
Esδ(
Es−
EF) is very small in agreement with the observations: If the Fermi level crosses the four bands
Δg becomes essentially zero, while the crossing with the three bands A
−, B
+ and A
+ makes
Δg finite but still small in the magnitude. Each
Δg(
Es) is very sensitive to the potential difference between the bounding and interior layers.
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G. K. Johri
1984 Volume 53 Issue 2 Pages
802-806
Published: February 15, 1984
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A new method of calculation of dipole moment and the relaxation time for dilute solutions of organic liquids at microwave frequency is proposed. The calculations are done with and without Cole-Cole distribution parameter. This method interprets the dielectric data and give dipole moment values in close agreement with those obtained by Guggenheim method.
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Kenji Ema, Takuya Kato, Katsumi Hamano
1984 Volume 53 Issue 2 Pages
807-810
Published: February 15, 1984
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The complex dielectric constant of K
2ZnCl
4 was measured in the frequency range from 100 MHz to 800 MHz around the incommensurate-commensurate phase transition point
Tc. A nearly Debye-type dispersion was observed, of which the relaxation time showed a critical slowing down. The relaxation frequency was about 50 MHz at
Tc. The static dielectric constant above
Tc obeys the Curie-Weiss law with the Curie constant of about 95 K. Both the static dielectric constant and the relaxation time showed thermal hysteresis in the incommensurate phase.
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