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Kazumasa Miyano, Tomoaki Ando, Hisaki Kudo, Minoru Yanokura, Hiromichi ...
1978 Volume 45 Issue 4 Pages
1071-1075
Published: October 15, 1978
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Cross sections and mean projected ranges of the recoil ions for
209Bi(
p,
n) reaction with
Ep from 18 MeV to 64 MeV were obtained. The cross sections were analysed both by the hybrid model and by the geometry dependent hybrid model. The geometry dependent hybrid model was found to reproduce the experimental (
p,
n) cross sections upto
Ep of 64 MeV, while the calculated cross sections by the hybrid model deviate from the experimental ones at the proton energies higher than 40 MeV. Dependence of decay rates of the exciton states on the nuclear density was discussed and it was concluded that the pre-compound model is essentially concerned with averaging of the doorway states. Recoil ranges of the reaction residuals were analysed, introducing a 90° asymmetry term
P1(cos θ) for the angular distributions of the residuals in CM system.
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Yuuki Kawarasaki
1978 Volume 45 Issue 4 Pages
1076-1084
Published: October 15, 1978
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An experiment has been made on the nuclear resonant scattering from natural tin using thermal-neutron-capture γ rays in natural lead. Improvements have been made on both the equipment and methods of measurement in the spectrometer system. The results obtained are as follows; 1) the isotope responsible for the resonance is found to be
120Sn, 2) resonance occurs at 6729.8-keV γ rays from
204Pb(n, γ), 3) the spin of the level is assigned as 1, 4) the ground-state transition width
Γ0 is 0.03±0.01 eV with a branching ratio
R of 0.88±0.08 and 5) the effective absorption cross section 〈σ
abs〉 is 0.48±0.05 b and the separation δ between the energies of the incident line and the resonance level is 1.0±0.3 eV.
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Yuuki Kawarasaki
1978 Volume 45 Issue 4 Pages
1085-1091
Published: October 15, 1978
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An experiment has been made on the nuclear resonant scattering from natural tin using thermal-neutron-capture γ rays in vanadium. Two levels were found to be simultaneously excited; one is the 7310-keV (
J=1) level in
120Sn and the other the 6517-keV (
J=3⁄2) level in
117Sn. Decay schemes of the resonant levels are proposed, Level parameters, such as effective cross sections, total radiative and ground-state transition widths, branching ratios and separations between energies of the incident line and the resonance, are deduced.
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Hajime Ohnuma, Jirohta Kasagi, Yuichi Iritani, Norio Kishida
1978 Volume 45 Issue 4 Pages
1092-1098
Published: October 15, 1978
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Gamma rays from the
59Co(α, pγ)
62Ni reaction were observed in coincidence with protons at
Eα=8 MeV. Lifetimes of excited states in
62Ni were determined by the Doppler-shift attenuation method. The
B(E2) values obtained for the 2
1+ and 2
2+ states are in good agreement with the shell-model calculations with
eeff=1.7, while
B(E2, 4
1+→2
1+) is much larger and
B(E2, 4
2+→2
1+) much smaller than the shell model values. Decay scheme of the states in
62Ni up to 4.16 MeV are also discussed.
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Jirohta Kasagi, Hajime Ohnuma
1978 Volume 45 Issue 4 Pages
1099-1110
Published: October 15, 1978
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Gamma-ray angular distributions, γ-γ coincidences and Doppler-shift attenuations have been measured in the
48Ti(α, nγ)
51Cr and
50Cr(α, nγ)
53Fe reactions. Linear polarization of γ rays from the
48Ti(α, nγ)
51Cr reaction and excitation functions and angular distributions of γ rays from the
51V(p, nγ)
51Cr reaction have also been measured. Present data have established unambiguously the presence of a series of levels in
51Cr and
53Fe, which are most naturally interpreted as the members of
Kπ=1⁄2
− bands. They are 1/2
−, 3/2
−, 5/2
−, 7/2
−, 9/2
− and 11/2
− levels at 777, 749, 1353, 1557, 2379 and 2705 keV in
51Cr, and 1/2
−, 3/2
−, 5/2
− and 7/2
− levels at 774, 740, 1421 and 1695 keV in
53Fe. Lifetimes, branching ratios and mixing ratios of the transitions from these levels have been measured. Obtained reduced transition probabilities indicate that the
Kπ=1⁄2
− bands in
51Cr and
53Fe are more deformed than the yrast levels. It has been shown that there are many previously unresolved γ rays in
51Cr and the decay scheme of
51Cr levels has to be considerably modified.
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Yositaka Onodera, Yukito Tanabe
1978 Volume 45 Issue 4 Pages
1111-1118
Published: October 15, 1978
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Some points implicit in the Landau theory of second-order phase transitions are clarified. Lifshitz’s criterion is then directly derived by requiring the absence of
k-linear terms
Ak(
p,
T), the second-order coefficient in Landau’s expansion of free energy. It is shown that the presence of
k-linear terms leads to invariants bilinear in the order parameter and its spatial derivative as proposed by Lifshitz. The theory is developed in parallel with the shallow impurity problems in semiconductors and the
k·
p perturbation theory. Lifshitz’s criterion is shown to be equivalent to the absence of
k-linear terms in energy bands. The equivalence makes the application of Lifshitz’s criterion easier
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Yoshihiro Ishibashi, Vladimir Dvorák
1978 Volume 45 Issue 4 Pages
1119-1126
Published: October 15, 1978
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The existence of conical points in the dispersion relation in some hexagonal system is group-theoretically discussed. Invariants, including the Lifshitz invariant and the domain wall invariant, are obtained for the representation responsible for the appearance of the conical point. The phase transitions into the incommensurate and commensurate phases induced by the instability of such representation are discussed.
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Takasu Hashimoto, Katsuyuki Nishimura, Yoshiaki Takeuchi
1978 Volume 45 Issue 4 Pages
1127-1135
Published: October 15, 1978
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The transitional process in the Cu
3Au alloy from the disordered to the ordered state and the relaxation process in the phase change in Cu
3Au have been investigated by measuring the time dependence of the X-ray superstructure line width and the electrical resistivity. The process is realized by a rapid change of the sample temperature in comparison with the relaxation time of this process. The average cluster size increases in proportion to
t1⁄2 irrespective of the ageing temperature. This is compared with the theoretical result of Kawasaki
et al. The change of the distribution function of the size of the ordered clusters is obtained from the superstructure line shape. We observe two kinds of relaxation times τ
D→0 and τ
0→D. τ
D→0 from the disordered to the ordered state is comparatively long and shows a kind of the showing down phenomenon. In contrast to this, τ
0→D from the ordered to the disordered state does not show such slowing down near
Tt. By assuming an appropriate model, this relaxation phenomenon is explained.
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Atsushi Oshiyama, Kenji Nakao, Hiroshi Kamimura
1978 Volume 45 Issue 4 Pages
1136-1146
Published: October 15, 1978
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Electrical resistivity along the chain axis of quasi-one-dimensional metals is calculated using the Boltzmann equation on the quasi-one-dimensional band model which consists of two pairs of warped plane-like Fermi surfaces separated by about half the reciprocal lattice vector along the chain axis. It is shown that electron-electron Umklapp scattering is the most dominant mechanism contributing to resistivity. Furthermore it is predicted for the first time that electron-electron Umklapp scattering gives rise to the characteristic temperature dependence of resistivity such as
Tη where 2≤η≤3, depending on the band parameters. The observed temperature dependence of intrinsic resistivity in (SN)
x can be explained solely by the electron-electron Umklapp scattering, as far as the above quasi-one-dimensional Fermi surfaces are adopted.
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Kazuo Nakanishi, Hiroyuki Shiba
1978 Volume 45 Issue 4 Pages
1147-1156
Published: October 15, 1978
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A theoretical study is presented for the incommensurate (
I) state and the incommensurate-commensurate (
C) transition with McMillan’s single charge-density-wave model. The
I state is determined precisely by taking account of a sufficiently large number of harmonics. A domain-like
I state is obtained if the fundamental wave number is close to that of the
C state. At the domain boundary the amplitude of the order parameter decreases together with the change of the phase of the order parameter. The
I-
C transition of the model is shown to be of second order. A detailed study is also made on the collective modes for the domain-like
I state. Modes associated with domain boundaries are obtained.
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Hiroshi Katayama, Junjiro Kanamori
1978 Volume 45 Issue 4 Pages
1157-1164
Published: October 15, 1978
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A self-consistent theory of the lattice vibration in substitutionally disordered alloys which corresponds to an adaptation of Blackman, Esterling and Berk’s theory of the electronic structure calculation is proposed for the purpose of taking into account the force constant disorder. The result of the theory is compared in detail with experimental data on Ni–Pt alloys. Pd–Ag and Cr–V alloys are also discussed as examples demonstrating the effect of the force constant disorder.
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Daijiro Yoshioka
1978 Volume 45 Issue 4 Pages
1165-1173
Published: October 15, 1978
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The properties of an electron-hole system in a strong magnetic field is studied. Especially the effect of the excitonic correlation on the gas-liquid type phase transition is studied by a mean field theory. It is shown that the effective mass, number of carriers and Landau quantum number of the relevant Landau subbands have characteristic effects. It is suggested that a semimetal bismuth in a magnetic field of about 100 kOe shows various types of phase transitions at low temperatures (
T\lesssim0.1 K).
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Hidetoshi Miike, Tetsuya Okazaki, Tatsuhiko Kohno, Yoshio Ebina
1978 Volume 45 Issue 4 Pages
1174-1178
Published: October 15, 1978
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The electric power is measured in nematic
p-
methoxy benziliden p′-
n butyl aniline (MBBA) and mixtures of MBBA and
cholesteryl nonanoate (CN). The power increases linearly against to the square of the supplied voltage below the threshold voltage V
c, where the electrohydrodynamic instability occures. To see explicitly the increment of the power, the excess power is computed by subtracting the power obtained by the extrapolation of the ohmic relation from the measured power. Increasing the voltage, the excess power increases remarkably above V
c. In the cholesteric case, however, the excess power accompanied with the convection decreases anomalously above about 2V
c. This corresponds to the restabilization of the cholesteric planar texture with the pitch contraction. The difference of the transition-scheme between nematic (MBBA) and cholesteric (MBBA+CN) is discussed, and new term “exchange transition” is proposed for the electrohydrodynamic instability in cholesteric.
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Natsuki Mori, Tatsumi Sumi, Hajime Ozaki
1978 Volume 45 Issue 4 Pages
1179-1184
Published: October 15, 1978
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Two types of unusual behaviors in tunneling characteristics in sputtered Nb films have been observed. The first, there exists an additional peak in the phonon structure for junctions with well defined energy gaps. The second, oscillatory behaviors in the tunneling resistance versus voltage have been observed for junctions with poorly pronounced energy gaps. Some possible explanations for these results are described in comparison with recent experiments. Effect of observed dilated lattices on the superconducting transition temperature is also reported.
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Kazushi Sugawara
1978 Volume 45 Issue 4 Pages
1185-1190
Published: October 15, 1978
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The temperature dependence of the longitudinal NMR relaxation rate is theoretically studied for insulating magnetic systems, in which the impurity electronic spin has a substantial crystal-field splitting and the decay rate of the time dependent auto-correlation function of the impurity spin is dominated by the spin-lattice relaxation. The theory was applied to the NMR of F
19 in PrF
3 with small concentration of Nd
3+ as impurities, which was performed by Aukhadeev and Konov and revealed the electronic spin-lattice relaxation narrowing of the NMR line-width above 15 K. The present theory can qualitatively explain the anomalous temperature dependence of the F
19 NMR line-width in the system mentioned above. Possible mechanisms of the broadening of the NMR line-width are also considered.
This report is the first to study theoretically the NMR narrowing due to the joint effects of crystal-field and spin-lattice relaxation.
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Tadashi Sugihara, Kiiti Siratori, Isamu Shindo, Takashi Katsura
1978 Volume 45 Issue 4 Pages
1191-1198
Published: October 15, 1978
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Magnetic properties and electrical conductivity of the YFe
2O
4 single crystal were investigated. It was disclosed that YFe
2O
4 is an antiferromagnet whose Néel point is 205 K, and the spin lies parallel to the hexagonal
c axis. Below
TN, the magnetization parallel to the
c axis was not proportional to the magnetic field. A large rotational hysteresis was observed at temperatures between 170 and 120 K. Below 140 K, a weak but very hard ferromagnetic moment parallel to the
c axis resulted from field cooling. On the basis of these facts, a model of parasitic ferromagnetism, i.e., preferential location of Fe
2+ and Fe
3+ ions on each antiferromagnetic sublattice, is proposed. If such a preferential location is caused by the difference of the exchange interaction constant, YFe
2O
4 is the first example of an annealed random spin system.
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Hisao Kitaguchi, Takashi Watanabe
1978 Volume 45 Issue 4 Pages
1199-1203
Published: October 15, 1978
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Magnetic susceptibilities and specific heats of mixed crystals of Mn
xCd
1−x(NH
3)
2·Ni(CN)
4·2C
6H
6 have been measured on powder specimens from 0.20 K to 4.20 K. The Weiss temperature θ(
x) and the Néel temperature
TN(
x) for the concentration
x of magnetic ion Mn
2+ have been determined. θ(
x) is proportional to
x. The critical concentration
xc is estimated as 0.69 from
TN(
x). This value supports the assumption that Mn(NH
3)
2·Ni(CN)
4·2C
6H
6 is the psued-two dimensional Heisenberg antiferromagnet.
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Shuko Washimiya, Chikatoshi Satoko
1978 Volume 45 Issue 4 Pages
1204-1212
Published: October 15, 1978
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Molecular field equations for
Γ4,
Γ24 and
Γ2 phases of rare earth orthochromites and orthoferrites are derived and applied to the analysis of the observed magnetization in GdCrO
3. The Cr–Cr, Cr–Gd and Gd–Gd interactions are determined so as to fit the observed magnetization. The free energy is calculated by using these values of the parameters. It is shown that the single-ion anisotropy of the Gd
3+ ion and the Gd
3+–Gd
3+ interaction contribute to the magnetization below 10 K and to the free energy below 3 K, while the Cr
3+–Gd
3+ antisymmetric exchange interaction stabilizes the free energy below 10 K.
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Takehiko Oguchi, Takuma Ishikawa
1978 Volume 45 Issue 4 Pages
1213-1220
Published: October 15, 1978
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Magnetic properties of a mixture A
xB
1−x of two orthorhombic anisotropic antiferromagnets with different easy axes are investigated. The magnetic easy, intermediate, hard axes are
x,
z,
y axes for the pure A antiferromagnet, while
y,
z,
x axes for the pure B antiferromagnet, respectively. In the middle range of concentration, there appears a single kind of oblique antiferromagnetic phase (OAP) whose spins lie within
xy plane in one case, or two different OAP within
xz and
yz planes, respectively, in the other case. In the latter case,
z axis becomes the easy axis in some range of concentration. Applied magnetic field effect and the susceptibility at
T=0 are calculated. It is predicted that a mixture Ni
xCo
1−xCl
2·2H
2O would have the latter property.
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Yosiaki Tino, Yukihiro Nakaya
1978 Volume 45 Issue 4 Pages
1221-1225
Published: October 15, 1978
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In order to find a special feature of the crystalline structure in Fe–Ni Invar alloys, magnetic measurements and X-ray analysis were made after annealing the alloys in the two-phase (α+γ) region for ten thousand hours or more. It has been found that various transitional structures toward the α-phase are formed before the diffusion of concentration takes place, and the structures are stable in a wide temperature range from liquid nitrogen temperature up to near the melting point. This suggests that well-annealed Invar alloys also contain transitional structure in the form of small nuclei.
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Yosiaki Tino, Masaaki Kobayashi
1978 Volume 45 Issue 4 Pages
1226-1231
Published: October 15, 1978
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The effect of quenching on the thermal dilatation of the Fe–Ni Invar alloys has been studied by absolute thermal dilatation measurements. It is well known that the reversible alloy with 36%Ni possesses the lowest coefficient of dilatation. The present study shows that the quenched irreversible alloy with 34%Ni also indicates zero or negative thermal dilatation. And apparent two
As-points are detected in the irreversible Invar alloys. These observations suggest that a stable state in the γ-phase region is not the perfect γ-phase. The measurements of magnetic susceptibility in the para-process and X-ray analyses indicate that the states produced by quenching have some similarities to those by cold-working, which can be ascribed to a transitional structure far from the perfect f.c.c. lattice.
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Toshihiko Tokunaga, Hiroshi Fujiwara
1978 Volume 45 Issue 4 Pages
1232-1238
Published: October 15, 1978
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Magnetostriction constants of Ni–Pd alloys containing 0∼90 at% Pd were measured above 77 K with the (001) and (011) disks by means of a strain gauge technique. The higher order magnetostriction constants
h3∼
h5 were found to be negligibly small in comparison with the lower order constants
h1 and
h2. The values of
h1 and h
2 at 0 K determined by the extrapolation increase in magnitude with an increase of the Pd concentration, and reach the maximum of about −3.4×10
−4 and −1.6×10
−4 for
h1 and
h2, respectively, around 70 at% Pd. At 0 K, the contribution of the magnetoelastic term (
K1)
M.E. to the effective magnetic anisotropy constant
K1 was found to be negligibly small, so that it is possible to regard
K1 as the intrinsic magnetic anisotropy constant (
K1)
0. The concentration dependence of
h1 and
h2, and of (
K1)
0 is qualitatively discussed.
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Shoji Ishida, Junji Ishida, Setsuro Asano, Jiro Yamashita
1978 Volume 45 Issue 4 Pages
1239-1243
Published: October 15, 1978
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The energy bands of an ordered alloy Cu
2MnAl are calculated by the symmetrized augmented plane wave (SAPW) method. The
E(
k) curves and the densities-of-states curves are obtained. For up-spin (minority) electrons, the density-of-states curve has two peaks. They are separated by a wide low density region in which the Fermi level is situated. The upper peak arises from the
d-bands of Mn and the other one from those of Cu. On the other hand, for down-spin (majority) electrons, the state-density curves of
d-bands of Cu and Mn have two peaks respectively and they are overlapped with each other. Those bands are almost occupied. The main carrier of the magnetic moment is Mn atom. The magnetic moment of the alloy has been estimated to be 3.73 μ
B per molecule, which is in agreement with the measured values 3.6–4.12 μ
B.
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Yasunori Tanji, Hiroshi Moriya, Yasuaki Nakagawa
1978 Volume 45 Issue 4 Pages
1244-1248
Published: October 15, 1978
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The thermoelectric power of Fe–Ni alloys relative to Pt was measured up to 1050°C in the whole range of concentration. Great care was given to the phase transition of the alloys. The concentration dependence of thermoelectric power in the fcc phase at high temperatures shows a distinct anomaly around 50 at% Ni, suggesting that the alloys have the tendency to separation into two fcc phases. The so-called Invar problem is considered to be closely related to this anomaly.
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Akira Nagasawa, Yoshiko Ueda
1978 Volume 45 Issue 4 Pages
1249-1252
Published: October 15, 1978
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Besides the softening of (
C11−
C12)⁄2, another type of the elastic mode becomes soft as the preceding phenomenon of the martensitic phase transition in NiAl. It occurs in the
T2 mode along the special direction on the (110) plane in the β
1 phase. Such a lattice instability is responsible to the formation of the close packed planes in the martensite phase. This type of the elastic soft mode is expected to occur commonly in the β phase alloys as the preceding phenomenon of the martensitic phase transition.
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Satoru Inagaki
1978 Volume 45 Issue 4 Pages
1253-1260
Published: October 15, 1978
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Explanations of the physical properties of solid solutions Fe
xCo
1−xS
2 are given by the use of models taking account of the observation that Fe is a highly repulsive impurity atom for 3
d eg electrons on Co atoms. True Fe concentration dependence of the saturation magnetization and of the electronic-specific-heat coefficient are explained by a calculation using the CPA combined with Hartree-Fock approximation. A simple argument making use of the Friedel sum rule is given to discuss the change in the electrical resistivity by Fe impurities in CoS
2. A density-of-states curve for the
eg band of CoS
2 is proposed to account for these properties.
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Hiroyuki Kaga, John D. Dow
1978 Volume 45 Issue 4 Pages
1261-1265
Published: October 15, 1978
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The previously-unexplained
anomalous ramp-like linear optical absorption threshold of rare-gas impurities in alkali metal hosts [(
Ω−
ΩT)
−β with β≈−1] is shown to be a natural consequence of an extra-orbital relaxation model which leads to the
simultaneous creation of a conduction-band
hole and a conduction
electron in the final states.
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Hidetoshi Fukuyama
1978 Volume 45 Issue 4 Pages
1266-1275
Published: October 15, 1978
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Effects of the long range Coulomb interaction and the distribution of Br atoms are investigated on the charge density wave of KCP in connection with the experimental finding of long correlation length along the chain, ξ, even at relatively high temperatures. It is shown that the Coulomb interaction increase ξ appreciably, though experimental data indicates longer ξ than the theoretical estimate. In order to explain the experiment it is, then, argued based on the work of Kondo and Yamaji that the density correlation of Br
− atoms has large 4
kF-component, which leads to the commensurability pinning of the CDW through higher harmonics. This argument qualitatively explains the experimental data of the phonon gap and the pinning frequency at low temperatures.
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Shun-ichi Kobayashi, Yôichi Fukagawa, Seiichiro Ikehata, Wataru ...
1978 Volume 45 Issue 4 Pages
1276-1281
Published: October 15, 1978
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Detailed study of NMR line shape and spin-lattice relaxation time has been carried out on phosphorus doped silicon with a purpose of making clear the nature of the electronic state in samples which show intermediate or metallic impurity conduction. On the basis of these observations previously published pictures for metallic transition were reexamined. A picture that the Anderson localized states with “intra” state correlation exist over a wide range of donor concentration, including the critical concentration of metallic transition, is shown to explain the observed properties in a consistent way.
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Ko Sugihara
1978 Volume 45 Issue 4 Pages
1282-1286
Published: October 15, 1978
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Shklovskii derived an expression of the magneto-resistivity of lightly doped semiconductors in the variable range hopping region. According to his result the resistivity takes the form of ρ∝exp {const. [λ
2aHg(μ)
k0T]
−1⁄3} in strong magnetic field, where
aH denotes the field-dependent Bohr radius, λ the magnetic length defined by λ=\sqrth
c⁄
eH and
g(μ) is the density of states at the Fermi level μ.
However, the experiments carried out by Gershenzon
et al. revealed that ρ of highly compensated
n-InSb behaves quite differently from the Shklovskii’s prediction. Such discrepancy can be attributed to an assumption of constant density of states on which Shklovskii’s result is based. This assumption leads to an erroneous conclusion because in the case of highly compensated samples the density of states is strongly energy-dependent.
By extending the percolation theory to the strong magnetic field region and considering the energy-dependent density of states, a qualitative agreement with the observed data is obtained.
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Takeshi Hattori, Takayoshi Nishii, Akiyoshi Mitsuishi
1978 Volume 45 Issue 4 Pages
1287-1290
Published: October 15, 1978
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The temperature-dependent infrared absorption spectra due to an Li-localized mode in AgBr have been measured. It is shown that the halfwidth increases linearly with temperature
T for
T\gtrsim90 K, while it is constant for
T\lesssim20 K. The temperature dependence is interpreted as resulting from decaying of the localized mode into two lattice phonons. The integrated absorption intensity of the fundamental band is observed to decrease as
T2. The peak frequency slightly shifts to higher energy as the temperature increases in higher temperature region.
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Jun Hatano
1978 Volume 45 Issue 4 Pages
1291-1295
Published: October 15, 1978
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Calculations of the ferroelectric coercive field as a function of impressing rate of field have been made on the basis of a two-dimensional model of domain growth; a linear dependence of nucleus density on the applied fields and an anisotropy of sideways velocity of a domain wall motion are taken into account. Experimental results of coercive fields in TGS and TGSe which have been measured by the application of triangular fields are successfully explained by the present treatment. The contribution of newly created nuclei to the polarization reversal cannot be ignored in both crystals.
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Masaru Kasahara, Itaru Tatsuzaki
1978 Volume 45 Issue 4 Pages
1296-1301
Published: October 15, 1978
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Temperature dependence of electric field gradient (EFG) at Na site in NaD
3(SeO
3)
2 was studied by the first order shift of quadrupole interaction. The principal coordinate system of EFG at one Na site of the two rotates with varing temperature in the ferroelectric phase. The splitting of resonance lines in the ferroelectric phase shows different behavior against temperature in different direction of the magnetic field. Spontaneous polarization
Ps was measured on a temperature range from just below the transition to −127°C both along the
a and
c* axes. Results indicate that
Ps rotates in the
ac plane.
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Ikuo Suzuki, Kenkichi Okada
1978 Volume 45 Issue 4 Pages
1302-1308
Published: October 15, 1978
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Kittel’s free energy expression with all the fourth order cross terms of two sublattice polarizations was dealt with. Phase diagrams of four phases, the nonpolar, polar, antipolar, and semipolar phase, were calculated for various sets of expansion coefficients. For a set of coefficients, the semipolar phase is absolutely stable at zero field, and it is switched to the polar phase by external field indicating ferrielectric behaviors. Rather complicated relations of polarization and external field were calculated systematically corresponding to phase transitions among the four phases.
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Tatsuo Tokuoka
1978 Volume 45 Issue 4 Pages
1309-1312
Published: October 15, 1978
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The phenomenological theory of the plastic dielectrics is proposed, where the material is characterized by scalar and tensor internal state variables and has the general work-hardening. Two types of the optical constitutive equations are studied. One is the rate type and other is the non-rate type. The rate type equation is restricted by several constitutive assumptions and its explicit expression is obtained. The non-rate type equation is reduced to the form that the index tensor is a linear equation of the modified translated stress tensor. Then the birefringence and the extinction angle are represented by that tensor.
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Motoji Ikeya
1978 Volume 45 Issue 4 Pages
1313-1319
Published: October 15, 1978
Released on J-STAGE: June 01, 2007
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The structure and the dipolar reorientation of Mn
++-Vacancy complex, (Mn
++–V), have been studied with the measurements of electron paramagnetic resonance (EPR) and ionic thermocurrent (ITC) in NaCl doubly doped with Mn
++ and F
− ions. A new EPR signal of Mn
++–F
− complex with a vacancy at the nearest neighbor cation site (nn) was observed (Spectrum III
1F) in addition to the one with a vacancy at the next nearest site (nnn) observed by Yokozawa and Kazumata (Spectrum III
2F). ITC studies indicate that the orientation energies of a vacancy around Mn
++–F
− axis are 0.50, 0.53 and 0.58 eV in contrast to 0.67 eV for the orientation of Mn
++-vacancy complex. Three ITC activation energies are attributed to the corresponding jumps from nn to nn around Mn
++–F
− axis, from nn to nnn and from nnn to nn site, respectively. Energy states for a vacancy around Mn
++–V complex and (Mn
++–V)
F− are schematically shown.
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Teizo Tabata, Hiroshi Fujita, Hiroshi Kusuhashi
1978 Volume 45 Issue 4 Pages
1320-1326
Published: October 15, 1978
Released on J-STAGE: May 29, 2007
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The effect of surface layer on the deformation process of copper single crystals with various tensile axes has been investigated. The dislocation density of the surface layer is slightly higher than that of the interior at the yield point and it increases gradually with increasing strain. In the interior, increasing rate of dislocation density is higher and the dislocation tangles are well developed compared with those in the surface layer. The continuation time of slip traces observed by electron microscopy increases with increasing exposure time of specimens in air after electropolishing. Furthermore, the amount of unloading yield drop decreases when the surface layer is removed by electropolishing.
It is concluded from the results that the surface layer acts as the barrier against the mobile dislocation before the yielding but it promotes the deformation after the yielding.
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Masahiro Koiwa
1978 Volume 45 Issue 4 Pages
1327-1332
Published: October 15, 1978
Released on J-STAGE: May 29, 2007
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The effect of the vacancy concentration on the correlation factor has been investigated quantitatively. For a given vacancy concentration
Cv, the number of correlated jumps of a vacancy,
nc, can be defined, and this number is used for the calculation of the correlation factor. The deviation of the correlation factor from the value corresponding to an infinitely dilute vacancy concentration is less than 1% for
Cv=10
−3 and less than 0.2% for
Cv=10
−4. For usual experimental conditions, the correlation factor may be regarded as temperature independent.
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Chikatoshi Satoko, Masaru Tsukada, Hirohiko Adachi
1978 Volume 45 Issue 4 Pages
1333-1340
Published: October 15, 1978
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Discrete variational (DV) Xα cluster method is extended to ionic crystals with inclusion of the long-ranged Coulomb potential of the ions outside the cluster. As a typical example of partially ionic crystals, the surface and the bulk electronic structures of MgO crystal are calculated. The strong electric field, the reduction in the Madelung potential and the charge redistribution on the surface are found to be important factors for the formation of the surface state. Various features of the DV–Xα cluster method, such as the size and the shape dependence of the cluster, the effect of the exterior potential and so on are investigated.
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Keiichiro Nasu, Yosuke Kayanuma
1978 Volume 45 Issue 4 Pages
1341-1348
Published: October 15, 1978
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The polarization of emitted light from a localized electron in a crystal is calculated on the basis of the theory of the time resolved emission including the lattice relaxation. A three level system composed of an
s-like ground state,
x- and
y-like excited states is worked out as an example. The depolarization is found to occur around the time when the phonon wave packet passes the intersection of the two adiabatic potential energies of the excited states, and its probability conforms to the Landau-Zener formula under certain conditions.
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Fumihiro Sakuma, Hirohito Fukutani, Goro Kuwabara
1978 Volume 45 Issue 4 Pages
1349-1353
Published: October 15, 1978
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Optical spectrum of red HgI
2 in the A exciton region was studied by means of wavelength modulated reflectance and magnetic circular dichroism. Many fine structures are observed, some of which shift diamagnetically parallel to each other with an LO phonon energy interval. They are assigned as phonon replicas of the 2
s exciton.
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Fumiaki Kanô, Masao Doi
1978 Volume 45 Issue 4 Pages
1354-1359
Published: October 15, 1978
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A dynamical theory is presented for the helix-coil transition and the isotope exchange reaction in a short polypeptide chain. In this theory it is assumed that there is always one and only one helical sequence. The boundaries of the helix are assumed to move randomly along the chain. If we assume slow movement of the boundaries, our model theory explains the experimental results, i.e., the very low rate of the isotope exchange in the central portion of the chain and the site dependence of the rate.
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V. P. Arora, V. K. Agarwal
1978 Volume 45 Issue 4 Pages
1360-1363
Published: October 15, 1978
Released on J-STAGE: May 29, 2007
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Dielectric measurements have been recorded in the frequency range 0.75–3.0 MHz in nematic and isotropic phases of EBBA. Measurements in the nematic phase indicate a Debye-type dispersion. Two activation energies were obtained, one above 47°C (15.36 kcal./mole) and the other below 47°C (9.15 kcal./mole). Dielectric relaxation strength δε(=ε
0−ε
∞) also exhibits a peak at 47°C. These results may be explained by assuming the hindered rotation below 47°C and a relatively free rotation above 47°C of the molecules about a transverse axis under the nematic potential.
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Harukazu Iguchi
1978 Volume 45 Issue 4 Pages
1364-1371
Published: October 15, 1978
Released on J-STAGE: June 01, 2007
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Initial stage of linear turbulent heating of plasmas has been investigated by means of Thomson scattering of ruby laser light with an eight-channel polychromator. In a low density discharge (
ne\simeq5×10
12 cm
−3), an anomalously rapid electron heating was observed to start in association with the onset of the current driven ion acoustic instability. Flat-top velocity distributions of the electrons were observed after the onset of the instability, which was interpreted by the quasilinear diffusion process in the velocity space caused by the turbulent ion acoustic waves. In a high density discharge (
ne\simeq2×10
14 cm
−3), the applied pulse voltage generated skin current distributions disappearing in less than 0.6 μsec, while skin profiles of the electron temperature remained longer, say for 2 μsec. It is concluded that the observed rapid current penetration is also due to the anomalous resistivity caused by the current driven ion acoustic instability.
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Hiroshi Kubo, Sadao Nakamura, Tetsumori Yuyama, Minoru Hosokawa, Syuko ...
1978 Volume 45 Issue 4 Pages
1372-1379
Published: October 15, 1978
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Negative absorption for extraordinary waves by the weakly relativistic electrons with the energy less than 20 keV gyrating in a tenuous plasma confined in a mirror field is studied by the microwave transmission method. Typical amplification factor of approximately 30 dB for the input power of a few milliwatts is observed during both heating period and after-glow. The experimental results are best explained by the relativistic mass effect obtained by Bekefi
et al. for the energetic electron plasmas.
Further the formation and relaxation of the distribution function of the energetic electrons are studied through the analysis of the temporal variation of the negative absorption. New method of microwave diagnostics for the determination of energy distribution function of energetic electrons in the tenuous magnetized plasma is proposed.
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Shobu Kaneko, Masayoshi Taguchi
1978 Volume 45 Issue 4 Pages
1380-1384
Published: October 15, 1978
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The Ohm and Hall conductivities of a plasma composed of electrons and singly charged positive ions, are evaluated by use of the Boltzmann equation. Since the electron-to-ion mass ratio is small, the distribution function for ions is assumed to be Maxwellian. The distribution function for electrons is expanded in terms of Sonine’s polynomials (the Chapman-Enskog method). Numbers of the expansion terms are changed from 6 to 50, and the convergence of this method is examined. Both the Ohm and Hall conductivities evaluated from the expansion with 50 terms have accuracy of at least six decimal places for various strength of magnetic field.
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Seio Sengoku, Masayuki Nagami, Hikosuke Maeda, Satoshi Kasai, Toshihik ...
1978 Volume 45 Issue 4 Pages
1385-1393
Published: October 15, 1978
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Divertor actions for controlling the impurity are investigated in DIVA, The heat exhaust function reduces the electron temperature of the plasma which contacting to the first wall, thereby reduces the ion-sputtering yield. Cooling of the scrape-off plasma with gas feeding further advances this situation and suppresses the contamination by the high-
Z impurity. For a carbon and aluminum injection, the accumulation of impurities in the main plasma is reduced by the factor of 2–4 by the shielding action. The shielded impurities are rapidly guided into the burial chamber with a flow velocity roughly equal to that of the bulk scrape-off plasma. The back-flow of impurity ions from the burial chamber to the main plasma is verified to be small.
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Takashi Yabe, Keishiro Niu
1978 Volume 45 Issue 4 Pages
1394-1399
Published: October 15, 1978
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A new model of implosion is proposed and the possibility of stable imposion is discussed on the basis of this model. The model indicates a relaxation of the restrictions on the peak power and the culmination time of laser light required for pellet implosion
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Iwao Harada, Norihiko Ozaki
1978 Volume 45 Issue 4 Pages
1400-1409
Published: October 15, 1978
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Numerical investigations are made on the source-sink flows in a rotating cylinder. A finite difference method is used to solve the time-dependent full Navier-Stokes equations to an incompressible, viscous and axisymmetric flow. Computations are carried out for three cases with different Ekman numbers and a fixed aspect ratio. Transient aspects of flows are discussed focusing on the developments of the Ekman layers on both disks, and the
E1⁄4 layers vertically formed at the radii of a source and sink located on the upper and lower disk, respectively. Numerical results based on a similarity analysis of the nonlinear
E1⁄4 layer agree well with the experimental ones.
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Isamu Todo
1978 Volume 45 Issue 4 Pages
1410
Published: October 15, 1978
Released on J-STAGE: May 29, 2007
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