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Koichi Maruyama, Hirofumi Fujii, Saburo Homma, Hideki Okuno, Nobuyuki ...
1979 Volume 46 Issue 5 Pages
1403-1411
Published: May 15, 1979
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The momentum spectra of the photoproduced positive and negative pions from the reaction γ
p→ππ
N have been measured using a tagged photon beam in the energy range from 710 MeV to 950 MeV. A magnetic spectrometer at 40° in the laboratory system is used to detect positive and negative pions. A hodoscope array which surrounded the liquid hydrogen target was used to identify the double pion photoproduction process. From the measured momentum spectra, the cross sections of the reaction, γ+
p→
Δ+π were extracted. The results are well reproduced by the coherent sum of GIOPE rnodel and
s-channel resonance contributions.
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Masakazu Ichiyanagi
1979 Volume 46 Issue 5 Pages
1412-1419
Published: May 15, 1979
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The study of the behaviors of the roton excitation in a Bose system is performed on the basis of Bogoliubov’s procedure. The method of the present theory is a generalization of Bohm-Pines’ theory of electron gases to a quantum field theory. Rotons in our model are connected with the quasi-particles described by the translational motion in the condensate wavefunction, thus they are viewed just like as solitons in a nonlinear field theory. We will show that the roton-momentum
P0 is intimately linked to the vortical motion in the system. The rest energy of roton is also obtained.
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Yukio Okwamoto, Hajime Takayama, Hiroyuki Shiba
1979 Volume 46 Issue 5 Pages
1420-1427
Published: May 15, 1979
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Effects of the commensurability energy on the fluctuating incommensurate state in one-dimensional systems are investigated exactly by means of the transfer integral method on the basis of the generalized Ginzburg-Landau model. At low temperatures the fundamental eigenvalue equation of the method is solved by expanding it in powers of the temperature in analogy with the ordinary WKB method. Our analytic results on the low temperature behavior of the correlation length can be interpreted in terms of phasons and discommensurations. At intermediate temperatures various physical quantities are calculated numerically. In particular from the temperature dependence of the correlation length we determine the crossover point from the fluctuating incommensurate state to the commensurate state.
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Kazuhiro Takahashi, Motoyuki Tanaka
1979 Volume 46 Issue 5 Pages
1428-1433
Published: May 15, 1979
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The spin-1 Ising model with bilinear and biquadratic interactions is investigated using a generalized constant-coupling approximation with two parameters. Equations to determine these parameters are derived by minimizing the variational free energy. The averages of the dipolar and quadrupolar moments expressed in terms of these parameters are first ascertained to give exact results for a linear chain, then investigated in detail for the quadrupolar-coupled system in comparison with the molecular-field results. The pair-correlation and the heat capacity of this system are also investigated in connection with the phase transition. For the system with the bilinear and biquadratic interactions the effect of the anisotropy constant to the phase transition is discussed.
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Kazuo Nakanishi
1979 Volume 46 Issue 5 Pages
1434-1443
Published: May 15, 1979
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The one-dimensional charge-density-wave (CDW) state containing impurities is studied theoretically. The localized large-amplitude excitation is taken into account to determine the ground state of the commensurate (
C)-CDW state at absolute zero. It is shown that the long-range order of the
C-CDW is unstable against an arbitrarily weak impurity potential in spite of the existence of the commensurability energy. Investigations are also made on the impurity effect on the incommensurate (
I)-
C transition as well as the temperature dependence of the wave number of the
I-CDW. In this connection a mechanism is proposed for bringing the concave curvature in the temperature dependence of the wave number, which is observed in 2H-TaSe
2.
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Kazuyuki Matsui, Yoshika Masuda
1979 Volume 46 Issue 5 Pages
1444-1450
Published: May 15, 1979
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The transport coefficients in a Kondo superconductor have been calculated numerically in the framework of the Müller-Hartmann and Zittartz depairing theory. The calculations have been performed for the ultrasonic attenuation rate α
S and the thermal conductivity
KS. For certain typical values of
TK⁄
Tc0, where
TK is the Kondo temperature and
Tc0 is the superconducting transition temperature in the absence of magnetic impurities, the temperature variation of α
S and
KS shows very interesting behavior corresponding to the reentrance of superconductivity. Results are compared with the experimental data on the Zn–Mn system obtained by Lou and Bömmel for α
S and by Sánchez for
KS. Our calculations explain well the experimental data. They are also compared with the results based on the depairing theory by Abrikosov and Gor’kov and by Shiba.
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Yoshinori Takahashi, Tôru Moriya
1979 Volume 46 Issue 5 Pages
1451-1459
Published: May 15, 1979
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Magnetic and thermal properties of nearly ferromagnetic semiconductors are investigated on the basis of our spin fluctuation theory of itinerant electron systems. The couplings among the spin fluctuation modes of general amplitudes are taken into account by using a functional integral formalism within a local approximation, introducing a simple model for the local density of states. The negative mode-mode coupling at low temperatures and the saturation of the amplitude of local spin fluctuations at high temperatures seem to explain peculiar magnetic and thermal properties reported on FeSi.
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Shingo Ikeda, Taiichiro Haseda
1979 Volume 46 Issue 5 Pages
1460-1466
Published: May 15, 1979
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The relaxation phenomena near
TN in Co(HCOO)
22H
2O have been studied by means of AC magnetic susceptibility with frequency of 7 Hz∼1 MHz. The relaxation phenomena which are due to the magnetic domain or the spin cluster motion have been detected clearly and studied. The relaxation effect of the magnetic domain motion can be separated out from the “intrinsic” susceptibility peak which comes from the phase transition, by applying the small external static magnetic field, and/or by using the relatively high frequency. The relaxation of the magnetic domain motion affects the “intrinsic” susceptibility of the phase transition even above the transition temperature. So called “critical slowing down” or “critical speeding up” in the crystal would have been observed in much higher frequency than 1 MHz.
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Makoto Kobayashi, Koichi Katsumata, Toshikazu Sato, Yoshihito Miyako
1979 Volume 46 Issue 5 Pages
1467-1473
Published: May 15, 1979
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Specific heat measurement was performed on Fe
(1−x)Co
xCl
2·2H
2O system, which is a random mixture of two antiferromagnets with competing spin anisotropies. The temperature vs concentration phase diagram of this mixture is constructed from the measurement of the anomalies in the specific heat. Three kinds of order phases i.e., Fe-rich and Co-rich antiferromagnetic phases and a new ordered one (
T\lesssim10 K, 0.3\lesssim
x\lesssim0.8) are found.
The phase diagram shows clearly the existence of a tetracritical point. The critical lines in Fe
(1−x)Co
xCl
2·2H
2O system become roughly straight ones near the tetracritical point and meet at an angle, not tangentially.
The magnetic specific heat and the magnetic entropy of the mixture are obtained.
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Kengo Adachi, Masaaki Matsui, Masahiro Kawai
1979 Volume 46 Issue 5 Pages
1474-1482
Published: May 15, 1979
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Further investigations, succeeding to the works of J. Phys. Soc. Japan
26 (1969) 631 and
29 (1970) 323, on the magnetic properties of Co(S
xSe
1−x)
2 in the whole concentration ranges (0≤
x≤1) were performed by means of high magnetic field, electrical resistivity and low temperature X-ray diffraction measurements. The first kind magnetic transition was found in the ferromagnetic phase except CoS
2. The metamagnetic behaviors were observed in the ferromagnetic (0.89<
x<1.0) as well as paramagnetic (
x<0.89) phases. The saturation moment per Co atom was obtained to be 0.855 μ
B for CoS
2 and it decreased gradually with increasing Se content. The electrical resistivity in low temperatures showed a
T2-dependence. It was concluded that the itinerant electron model base on the spin fluctuation theory is more adequate than models based on a localized spin scheme.
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Masanori Arakawa, Hiroshi Ebisu, Taturu Yosida, Kazumi Horai
1979 Volume 46 Issue 5 Pages
1483-1487
Published: May 15, 1979
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EPR investigations of Gd
3+ impurity ions in KZnF
3 and KCdF
3 have been made at the temperatures 487, 300, 77 and 4.2 K for KZnF
3 and at 487 K for KCdF
3. The spectra for cubic symmetry have been observed and the spin Hamiltonian parameters in cubic crystalline field have been determined. At the temperature of 487 K, the fourth-order zero-field splitting parameters in the spin Hamiltonian show remarkable difference for both crystals as following values:
b4=−6.97×10
−4 cm
−1 for KZnF
3 and |
b4|=1.6×10
−4 cm
−1 for KCdF
3. This difference implies that Gd
3+ impurities substitute for different cubic sites. From the size consideration of the ionic radii among K
+, Zn
2+, Cd
2+ and Gd
3+, it is concluded that Gd
3+ substitute for 12-fold K
+ site in KZnF
3 and 6-fold Cd
2+ site in KCdF
3.
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Shigeho Tanigawa, Takashi Tsuchida, Yoji Nakamura
1979 Volume 46 Issue 5 Pages
1488-1491
Published: May 15, 1979
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The magnetic properties of the pseudobinary system, Pr
1−cLa
cAl
2, have been investigated in order to know the combined effect of the crystal field and magnetic dilution of Pr by La in PrAl
2. The Pr concentration dependence of the Curie temperature and magnetic moment of Pr
3+ in Pr
1−cLa
cAl
2 are reported and discussed in terms of the crystalline electric and molecular fields, suggesting that PrAl
2 has a bunched state as the ground state. A set of crystal field parameters in PrAl
2 is proposed to be
x=0.81 and
W=−0.53 meV.
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Masayuki Kawakami, Takao Goto
1979 Volume 46 Issue 5 Pages
1492-1495
Published: May 15, 1979
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The zero-field NMR signal in magnetic V(Ir
1−xPt
x)
3 with the Cu
3Au-type structure has been observed in the frequency range of 10–80 MHz by spin echo method at 1.7 K. The peak of the spectrum which is attributable to the
51V nucleus has a nearly constant frequency ∼55 MHz for
x≥0.69, corresponding to about −50 kOe. The dependence of the signal intensity on
x is interpreted as follows; the V atoms have magnetic moments when the number of the nearest neighbor Pt atoms is more than about nine. Since the spontaneous magnetization decreases at larger
x values, the antiparallel polarization to the V magnetic moment would be expected at Pt sites and would nearly cancel the V magnetic moment at
x=1.0 (VPt
3). VPt
3 is thought to have a magnetic ordering below 206 K, at which the electrical resistivity has an anomaly.
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Jun-ichiro Inoue, Hideji Yamada, Masao Shimizu
1979 Volume 46 Issue 5 Pages
1496-1503
Published: May 15, 1979
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The high-field susceptibility, local moments, the asphericity of the magnetic moments, the low temperature specific heat coefficient and the coefficient of
T2 dependence of the magnetization are calculated for fcc Fe–Ni alloys in the coherent potential approximation. The difference between the band widths of fcc Fe and Ni is taken into account. The subbands of
d-electrons with
t2g and
eg symmetries, which are deduced from the calculated energy bands for Ni and fcc Fe in the interpolation scheme, are used. The calculated results show a good agreement with the experimental results except the Invar region. It is shown that the first-order transition from the ferromagnetic to paramagnetic state occurs at about 30 at% Ni, where the magnetization vanishes suddenly, and the high-field susceptibility is not so large as compared with the observed results.
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Hideo Hasegawa
1979 Volume 46 Issue 5 Pages
1504-1514
Published: May 15, 1979
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Itinerant-electron ferromagnetism at finite temperatures is discussed by using the functional-integral method with two fields within the static and saddle-point approximations combined with the single-site approximation; a single atom of
a pure metal is regarded as an impurity embedded in the host which is treated by a kind of the alloy-analogy approximation. The amplitude of the local magnetic moment is shown to have a weak temperature dependence and to remain finite even in the paramagnetic state, where the spin susceptibility obeys an approximate Curie-Weiss law. Numerical calculations are made with the use of a simplified model for the density of states of bcc transition metals. Calculated results are discussed with reference to experimental data of iron.
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Toshiro Endo, Takao Kino
1979 Volume 46 Issue 5 Pages
1515-1521
Published: May 15, 1979
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The electrical resistivity due to dislocations in gold has been measured in the temperature range between liquid helium temperature and 300 K. The deviation from Matthiessen’s rule (DMR) of the dislocation resistivity is different from that of the impurity resistivity in the temperature dependence and the residual resistivity dependence. DMR of the dislocation resistivity cannot be explained by the mechanism due to an anisotropic electron distribution function. Other two mechanisms due to phonon localized modes associated with dislocations and to electron levels localized near dislocations, are considered. In conclusion DMR of the dislocation resistivity is explained fairly well by a model of electron localized levels associated with dislocations.
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Hidetoshi Fukuyama, Kei Yosida
1979 Volume 46 Issue 5 Pages
1522-1528
Published: May 15, 1979
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We recently proposed that the Zeeman shift of the occupied states leads to a large negative magnetoresistance in the Anderson localized states. In this paper we considered the effect of electron correlations in the same Anderson localized state and found an apparent linear dependence on the magnetic field of negative magnetoresistance at low temperatures, which explains the experimental data of 1
T-TaS
2 by Kobayashi and Muto.
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Fusayoshi J. Ohkawa
1979 Volume 46 Issue 5 Pages
1529-1537
Published: May 15, 1979
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A variational formulation is presented in order to discuss the shallow donor states in Si. The theory is a combined one of the linear combination of atomic orbitals (LCAO) approach and the effective mass approach. It is shown that the central cell corrections play significant roles in 1
s donor states, and that they should be expressed in a symmetry dependent form. The chemical shifts of the donor states are easily obtained. The observed binding energies and Fermi contact hyperfine interaction constants are reasonably explained.
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Mitsuo Yamaga, Hide Yoshioka
1979 Volume 46 Issue 5 Pages
1538-1545
Published: May 15, 1979
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Electron spin resonance study shows that holes in Cl-rich AgBr
1−xCl
x mixed crystals are self-trapped as the Ag
2+ complexes having Br ligand ions, (AgBrCl
5)
4−, (AgBr
2Cl
4)
4− I, II and (AgBr
4Cl
2)
4− besides (AgCl
6)
4−. The complexes (AgBr
2Cl
4)
4− II and (AgBr
4Cl
2)
4− which have two and four Br ligand ions in the same plane respectively have the tetragonal symmetry due to the crystalline field created by Br ions and the Jahn-Teller effect. The anisotropy in
g values for these complexes is, however, reduced somewhat compared with that expected by the static Jahn-Teller effect. The decay temperatures of the complexes (AgCl
6)
4− and (AgBrCl
5)
4− are decreased with the increase of the concentration of Br ions. This fact is discussed with the theory of optical-phonon-assisted hopping.
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Sadao Adachi, Yasuo Itoh, Chihiro Hamaguchi
1979 Volume 46 Issue 5 Pages
1546-1553
Published: May 15, 1979
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The resonance data of Brillouin scattering by the acoustic phonon domains have been analyzed for ZnSe (slow-TA and fast-TA modes), ZnTe (slow-TA and fast-TA modes) and CdS (slow-TA, fast-TA and LA modes) in the photon-energy region near the fundamental absorption edges with a theoretical description based on the quasi-static approximation. The present analysis indicates that the Brillouin-scattering efficiency can be represented by the first derivative of the dielectric constant with respect to the incident-photon energy. The theoretical calculation has been performed by numerically differentiating the experimental data of the dielectric constant. The resonance behaviors of Brillouin scattering have been well interpreted by the quasi-static approximation when the non-dispersive contributions are properly taken into account. The quasi-static approximation has also indicated clearly that resonant Brillouin scattering is quite equivalent to the first-derivative modulation spectroscopy.
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Tohru Suemoto, Hiroshi Kanzaki
1979 Volume 46 Issue 5 Pages
1554-1562
Published: May 15, 1979
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The triplet self-trapped excitons (STE) in liquid and solid rare gases are investigated by means of absorption and luminescence spectroscopy under pulsed electron beam excitation. Absorptions from
3Σu state of molecular-type STE are observed in Ne, Ar, and Kr, and an intense band in the near infrared region is ascribed to the
3Σu→
Πg Rydberg type transition. In solid and liquid Ne, the 3s–3p Rydberg transitions from
3P
2 state of atomic-type STE are found, in addition to the molecular-type STE. The radiative lifetime of
3Σu is also determined for Ar and Kr from decay of the vacuum UV luminescence, and is found to agree with that of the absorption from
3Σu; the lifetimes are 1.41±0.05 μsec and 0.09±0.005 μsec for solid Ar and Kr, respectively.
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Kazumi Niimori, Yasutoshi Nakagawa, Kenzi Hukuda
1979 Volume 46 Issue 5 Pages
1563-1570
Published: May 15, 1979
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ESR spectra of Cr
3+ at K-site in KH
3(SeO
3)
2 crystal have been studied. Below
Tc, there are two kinds of inequivalent Cr
3+ sites whose principal coordinate systems (
X,
Y and
Z) of D-tensor are slightly rotated around
Z-axis each other. The critical exponent value β was estimated to be 0.50±0.02 from the difference in principal value between the two inequivalent sites. The experimental results indicate that reorientation of SeO
32− groups is accompanied by proton ordering and K ion displacement in the
ac plane perpendicular to the O(2)–H(2)–O(2) bond direction below
Tc. ESR spectra corresponding to single domain were observed by application of shear stress
X4.
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Masanori Arakawa, Hiroshi Ebisu
1979 Volume 46 Issue 5 Pages
1571-1579
Published: May 15, 1979
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An EPR investigation of Cr
3+-nearest neighbour Cd
2+ vacancy center in KCdF
3 has been made over a temperature range 290–490 K. The temperature dependence of the spectrum in the [100] field direction evidently shows the presence of the successive phase transitions at 485 and 471 K, From the field direction dependence for the magnetic field in the (011) and (001) planes, it was found that the induced
X-mode is not condenced significantly in the third phase below 471 K and so the first and second phase transitions can be explained by the condensation of the
M3 and
R25x+
R25y soft phonon modes at the [110] and [111] zone boundary in the cubic Brillouin zone, respectively.
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Yoshihiro Goto, Etsuro Sawaguchi
1979 Volume 46 Issue 5 Pages
1580-1582
Published: May 15, 1979
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Electric conductivity of ferroelectric Pb
5Ge
3O
11 single crystal was measured near the Curie point, θ
f=177°C. An a.c. method was adopted at very low frequency range of several Hz. At the low frequency limit the conductivity represents approximately the bulk d.c. conductivity. Near and above the Curie point, the crystal is semiconductive, σ∼10
−6 Ω
−1m
−1. Activation energies estimated from the conductivity data taken at 1.8 Hz, along
c-axis and
a-axis, respectively, are
ΔUc=1.6
0 eV,
ΔUa=1.4
4 eV in the ferroelectric phase, and
ΔUc=1.4
1 eV,
ΔUa=1.2
8 eV in the paraelectric phase, respectively.
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Noriyuki Akaba, Shigeo Suzuki, Mieko Takagi
1979 Volume 46 Issue 5 Pages
1583-1593
Published: May 15, 1979
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Three dimensional structure of antiparallel ferroelectric domains formed in
c-plates of BaTiO
3, partly covered with electrodes, has been studied by X-ray topography. Outside the electrodes, clusters of needle-like domains of about (10 μm)
2 in cross section due to the leakage field were observed. These clusters were nucleated from the surface with the negative electrode and almost all of the needle-like domains have terminated inside the crystal near the opposite surface with positive electrode. At the domain boundaries of large domains and at the walls of these needle-like domains, the crystal lattice is strained with the strain field parallel to the
c-axis. Under an optical microscope domains are visible with very poor contrast due to the reflexion of light at the domain walls.
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Masahiro Inoue, S. G. Chung
1979 Volume 46 Issue 5 Pages
1594-1601
Published: May 15, 1979
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Dynamics of sine-Gordon solitons and bions under constant electric field are investigated numerically and interesting phenomenon of dissociation of bions into soliton-antisoliton pair is observed. The feature of the bion dissociation depends on the initial phase of the bion and the electric field. For intermediate strength of the electric field, there are cases that the bion dissociates into two pairs of solitons and antisolitons. In strong field, the equation changes gradually into linear differential equation with random modulation.
A possible explanation based on the bion dissociation is proposed for the interpretation of the non-ohmic conductivity observed in TTF–TCNQ at lowest temperature.
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Shinji Hayashi, Junzo Hirono, Hitoshi Kanamori, Raphael Ruppin
1979 Volume 46 Issue 5 Pages
1602-1607
Published: May 15, 1979
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The frequencies of long-wavelength normal modes of a stab consisting of small spheres are calculated by using a dipole-dipole interaction Hamiltonian proposed by Clippe, Evrard and Lucas. Two optically active modes are found, one with a frequency lower than the Fröhlich mode frequency ω
F and the other with a frequency higher than ω
F. It is shown that for a thick enough slab the frequencies of the active modes coincide with those derived from the Maxwell-Garnett theory. This result indicates that the Maxwell-Garnett theory is reliable, even though it takes into account only approximately the dipole-dipole interaction.
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Toshio Takahashi, Seishi Kikuta
1979 Volume 46 Issue 5 Pages
1608-1615
Published: May 15, 1979
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Variations of the yield of silicon
K-photoelectrons are observed under two asymmetric diffraction conditions with the asymmetry factors of
b and 1/
b. The 220 Bragg-case diffractions of silicon are used for Cu
Kα radiation in the double-crystal arrangements. Anomalous changes found in two cases show a great difference, which is explained by the fact that the wave fields formed in the crystal in two cases are different from each other. The wave fields formed near the crystal surface are discussed in detail. The observed curves agree fairly well with the calculated ones.
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Hironobu Fujii, Shigehiro Komura, Takayoshi Takeda, Tetsuhiko Okamoto, ...
1979 Volume 46 Issue 5 Pages
1616-1621
Published: May 15, 1979
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Polarized neutron diffraction study of Fe
2P single crystal has been carried out at liquid nitrogen temperature. The magnetic moments and magnetic form factors on both the tetrahedral Fe
I and the pyramidal Fe
II atoms have been determined from the observed flipping ratios for 21 different (
kh0) reflections up to sin θ⁄λ∼0.71 A
−1. The magnetic moments are μ
I=0.92±0.02 μ
B and μ
II=1.70±0.02 μ
B for Fe
I and Fe
II site atoms, respectively. The magnetic form factor on Fe
I atom is noticeably different from that on Fe
II atom. The results are explained as being due to the different degree of the covalent bondings with surrounding P-atoms for both Fe atoms.
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Tetsuo Nagata
1979 Volume 46 Issue 5 Pages
1622-1627
Published: May 15, 1979
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Formation of H(2s) atoms in charge exchange collisions of protons with Cs, Rb, K and Na atoms has been studied for the proton energy
E ranging from 0.2 keV to 4.0 keV. The metastable atom fractions
f2s of neutral hydrogen H
0 beams produced under single-collision condition, which is regarded as the ratio of ‘total’ cross section for the charge exchange reactions eventually leading to formation of H(2s) atoms to total charge exchange cross section, have been determined as a function of
E. All of the
f2s(
E) curves obtained exhibit a marked structure, and the
f2s(
E) values vary between 0.18 and 0.38 with an average value of about 0.25 in this energy range. In the case of Cs target, the dependence of the yield of H(2s) atoms as well as the fraction
f2s on the target atom thickness in units of atoms/cm
2 has also been examined.
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Hisato Hiraishi, Tamotsu Kondow, Tsutomu Fukuyama, Kozo Kuchitsu
1979 Volume 46 Issue 5 Pages
1628-1634
Published: May 15, 1979
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Long-lived highly excited hydrogen molecules (H
2**) were produced by low-energy electron impact on H
2, and allowed to collide with H
2O and SF
6. The resulting H
2+ ions were observed by a quadrupole mass spectrometer. It was confirmed by the threshold energy, 15.4±0.3 eV, and by field ionization that the precursor of H
2+ was the H
2 molecule in high Rydberg states, their principal quantum numbers being estimated to be between 20 and 40. The shape of the excitation function suggested that H
2** molecules were mainly produced by optically forbidden transitions. The ionization cross sections of H
2** and D
2** with H
2O were estimated by the dependence of the H
2+ and D
2+ intensities on the H
2O pressure to be (3.8±1.0)×10
−13 and (5.5±1.5)×10
−13 cm
2, respectively. The average kinetic energy of H
2** was calculated by a TOF measurement to be 75±10 meV.
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Kazumi Ohasa, Hikosuke Maeda, Shin Yamamoto, Masayuki Nagami, Hideo Oh ...
1979 Volume 46 Issue 5 Pages
1635-1640
Published: May 15, 1979
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The metal impurity origin is studied in DIVA which is a tokamak with an axisymmetric divertor. Ion sputtering is demonstrated to be the dominant process of the release of gold from the shell coated with gold. A cone-like formation due to the sputtering is found on the gold protection plate exposed to about 10000 discharge by using the scanning electron micrograph technique. The SEM pictures shows that the spatial distribution of the cone-like formations on the shell surface due to the ion sputtering is well correlated with the spatial distribution of the intensity of the Au–I line radiation. It is also demonstrated that a honeycomb structure can decrease the release of the metal impurity.
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Toshitaka Idehara, Mataharu Tanaka, Yoshio Ishida
1979 Volume 46 Issue 5 Pages
1641-1646
Published: May 15, 1979
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The fast cyclotron wave excitation resulting from the coupling with the electron Bernstein wave is observed in a magnetized plasma penetrated by a spiral electron beam. For the excitation to occur, the beam energy component perpendicular to the magnetic field is larger than a critical value. From measurements of the wave number and the growth rate of the excited cyclotron wave, its dispersion relation is determined for various values of beam and plasma parameters. The experimental results are compared with the theoretical considerations.
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Hideo Sugai, Kazuo Ido, Hiroshi Niki, Susumu Takeda, Kunioki Mima
1979 Volume 46 Issue 5 Pages
1647-1652
Published: May 15, 1979
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The propagation of linear whistler waves is investigated in a plasma where the field-aligned density trough is produced without electron heating, in the artificial way different from previous experiments. Whistler waves are observed to be trapped in the narrow trough of width 2
d\lesssimλ
⁄⁄ (parallel wave length). The phase and amplitude profile of ducted whistlers is measured along and across the trough, controlling the density depth
Δne arbitrarily. The transverse amplitude decay outside the trough is found to become maximum at critical frequency. The measured transverse decay-length as well as the wave dispersion is in quantitative agreement with the trapping theory.
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Shinsuke Watanabe, Makoto Miyakawa, Nobuo Yajima
1979 Volume 46 Issue 5 Pages
1653-1659
Published: May 15, 1979
Released on J-STAGE: June 01, 2007
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In this paper, we solve the nonlinear Schrödinger equation of the form, (
Remark: Graphics omitted.), by means of conservation laws. For ε=0, the two soliton solution is obtained and is compared with numerical solution. For ε≠0, we consider plasma waves with linear and nonlinear Landau damping and obtain an approximate one soliton solution where the amplitude or velocity changes in time.
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Tetsuro Suzuki
1979 Volume 46 Issue 5 Pages
1660
Published: May 15, 1979
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Taturu Yosida, Hiroaki Aoki, Hideo Takeuchi, Masanori Arakawa, Kazumi ...
1979 Volume 46 Issue 5 Pages
1661-1662
Published: May 15, 1979
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Using 34 GHz band, the spin-Hamiltonian parameters of Cr
3+, Mn
2+, Fe
3+ and Co
2+ centres with cubic symmetry and Ti
3+ centre with tetragonal symmetry in LiBaF
3 have been determined. Co
2+ ion with
g=4.316 indicates that it substitutes for the Li
+ ion which is surrounded by a fluorine octahedron.
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Akio Yoshimori, Hisao Fukuda
1979 Volume 46 Issue 5 Pages
1663-1664
Published: May 15, 1979
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A model is proposed to explain the weak ferromagnetism of NiS
2. A term in the free energy, allowed in the presence of the mixed spin structure of the first kind and the second kind on the fcc lattice of Ni ions, is found to lead to a canted weak ferromagnetism. Comparison of theoretical results with the experimental ones is satisfactory.
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Yoshitoshi Muraoka, Shigehiro Kimura, Masayuki Shiga, Kenji Sumiyama, ...
1979 Volume 46 Issue 5 Pages
1665-1666
Published: May 15, 1979
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The low temperature thermal expansions of the Fe
72Pt
28 Invar alloy were measured. The thermal expansion coefficients in both ordered and disordered states are small, negative and linear in T. No appreciable difference has been detected between the two states. The magnitude of the linear negative thermal expansion coefficients is about five times as small as that of the Fe
66Ni
34 Invar alloy, which is interpreted in terms of strong ferromagnetism of Fe–Pt Invar alloys in contrast to weak ferromagnetism of Fe–Ni Invar alloys.
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Akito Sakemoto, Ken-ichi Kumagai, Kunisuke Asayama
1979 Volume 46 Issue 5 Pages
1667-1668
Published: May 15, 1979
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NMR of
55Mn in (Pd
0.996Co
0.004)
1−xMn
x alloys in a giant moment ferromagnetic and a spin glass state has been observed down to 100 mK. The narrow NMR line at about 405 MHz shifts slightly to lower frequency side with
x for
x≥4%, which indicates a partial cancellation of the contribution of hyperfine field from the neighboring impurities in the spin glass state. No abrupt change in the relaxation time has been found through the phase change from the ferromagnetic to the spin glass state.
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Kenji Nakao
1979 Volume 46 Issue 5 Pages
1669-1670
Published: May 15, 1979
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Magnetic energy level structures of superlattices are investigated. Due to the small band width in the direction of the superlattice axis, the dispersion of the band structure in this direction is essential for the determination of magnetic energy levels in the magnetic field perpendicular to the axis, and it is shown that the line spectrum of usual Landau levels for the parabollic band broadens into the band spectrum in this case. The density of states of magnetic energy bands is shown to have the divergence due to the two-dimensional van Hove singularities.
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Hirohiko Adachi
1979 Volume 46 Issue 5 Pages
1671-1672
Published: May 15, 1979
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The discrete variational Xα cluster calculations have been applied to chemisorptions of chalcogens on nickel. The calculated level structures of the XNi
5 clusters (X=S and Se) show good agreement with experimental UPS and INS spectra. The results show that the adsorptions of S and Se on nickel have stronger covalent character than the oxygen adsorption.
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Masahiro Mori, Yasusada Yamada
1979 Volume 46 Issue 5 Pages
1673-1674
Published: May 15, 1979
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The crystals of Tl
2PbCu(NO
2)
6 and Rb
2PbCu(NO
2)
6 undergo two phase transitions successively due to cooperative Jahn-Teller effect. The property of these transitions is studied by X-ray measurements. It has been shown that the intermediate phases of both substances have the sinusoidally modulated structures. The modulation wave vector lies along the [110] direction. The value of the wave vector changes smoothly when the temperature is varied, which confirms that the periodicity of the intermediate phases of these substances is incommensurable to the original lattice.
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Kanemitsu Kato, Kunioki Mima
1979 Volume 46 Issue 5 Pages
1675-1676
Published: May 15, 1979
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Momentum balance equations for electrons and ions are derived correct to the second order with respect to high frequency electric fields within the frame-work of the quasilinear theory. In particular, the stress tensor modification due to drift waves is evaluated from the second-moment equation. The ion drift caused by the gradient of the stress tensor breaks the ambipolarity of the diffusion. Strong electric fields across the ambient magnetic field are induced by the broken ambipolarity.
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Shunjiro Ikezawa, Yoshiharu Nakamura
1979 Volume 46 Issue 5 Pages
1677-1678
Published: May 15, 1979
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A physical meaning of the higher-order Landau mode is proposed from the theoretical calculation of the dispersion relation. When the plasma is composed of two electron temperatures, the dispersion relation of the two-temperature mode (the modified fundamental Landau mode) suddenly merges into one of the next higher-order Landau modes in the region ω⁄ω
p<1 (ω
p: electron plasma frequency) as the temperature of the small high energy tail in the velocity distribution increases.
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Hideo Kozima, Fumiko Tsuboi, Keiichiro Yamagiwa
1979 Volume 46 Issue 5 Pages
1679-1680
Published: May 15, 1979
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Plasma density increment is calculated when the ion energy is increased transversely in a magnetic mirror in stationary scheme. Increase in the transverse energy of ions decreases number of ions with velocities in the loss cone. Electron density is assumed to be equal to ion density. It is found that the relative change of the plasma density is proportional to the relative change of the transverse ion energy and the coefficient of the proportionality is given.
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Ryogo Hirota
1979 Volume 46 Issue 5 Pages
1681-1682
Published: May 15, 1979
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The Bäcklund and inverse scattering transforms are obtained for the Korteweg-de Vries equation with various nonuniformity terms
ut+6
uux+
uxxx+[α(
x,
t)
u]
x+γ(
t)
u=
Fx(
x,
t),
provided that the three functions α(
x,
t), γ(
t) and
Fx(
x,
t) related to the non-uniformities of the system, are constrained by the compatibility condition.
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