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Yuichi Kubota, David C. Rahm, Sukeyasu S. Yamamoto
1977 Volume 43 Issue 3 Pages
735-740
Published: September 15, 1977
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The cross section for the reaction K
−+p→
Λ+η was measured as a function of the incident K
− momentum in the vicinity of the reaction threshold. The excitation function for this reaction including earlier data confirms the existence of
Λ (1670) with a mass and width of 1668 MeV/c
2 and 15 MeV/c
2 decaying into
Λη with x
e1x
Λη=0.040. In addition, the behavior of the excitation function as well as the
Λ angular distributions and polarization strongly suggest the existence of
Λ (1690) with a mass and width of 1680 MeV/c
2 and 10 MeV/c
2 decaying into
Λη with x
e1x
Λη=0.025.
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Jirohta Kasagi, Shigeru Nakagawa, Norio Kishida, Yuichi Iritani, Hajim ...
1977 Volume 43 Issue 3 Pages
741-754
Published: September 15, 1977
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A detailed investigation of the electromagnetic properties of the
49Cr levels below 3 MeV has been made. The levels were populated by the
46Ti (α, nγ)
49Cr reaction at E
α=8 MeV. Analysis of measured gamma-ray angular distributions, linear polarizations, and gamma-gamma angular correlations has given the following unique spin and parity assignments: 9⁄2
− to the 1083-keV level; 1⁄2
− to the 1703-keV level; 5⁄2
+ to the 2432-keV level; and 7⁄2
− to the 2503-keV level. In addition, a unique 5/2 assignment has been given to the 2168-keV level. Lifetimes of some levels have been obtained from Doppler-shift attenuation measurements. New or revised values of branching ratios and mixing ratios have been determined for many transitions. The unique 5⁄2
+ assignment to the 2432-keV level and a large B (E2) value obtained for the transition to the 1981-keV 3⁄2
+ level suggest that the 2432-keV level is a member of the K
π=3⁄2
+ band built on the 1981-keV level.
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Katsuji Koyama, Noriyoshi Nakanishi, Shigeru Takeda, Satoru Yamada, Ha ...
1977 Volume 43 Issue 3 Pages
755-759
Published: September 15, 1977
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The
28Si (
3He, d)
29P reaction has been studied at an incident energy of 29.3 MeV. Comparisons of DWBA and CCBA analyses of angular distributions for low-lying bound states show that channel-coupling effect is not important except for stripping to the 1.95-MeV 5⁄2
+ state. Angular distributions for resonance states are analyzed by using Gamow functions as form factors for DWBA calulations. Such a description gives a reasonable account of the experimental angular distributions except that it fails to reproduce experimentally observed
j-dependence.
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Hideo Nagayoshi
1977 Volume 43 Issue 3 Pages
760-763
Published: September 15, 1977
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The pressure coefficients of the band parameters γ
0∼γ
5 and
Δ of graphite have been calculated from first principles by an OPW-like method of band calculation. As for γ
1 and γ
2 the obtained values (dlogγ
1⁄dP=0.020 and dlog|γ
2|⁄dP=0.036 kbar
−1) are of the same magnitude as earlier estimates, but dlog|
Δ|⁄dP (obtained to be 0.031 kbar
−1) is much smaller than previously reported values.
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Takehiko Oguchi, Yohtaro Ueno
1977 Volume 43 Issue 3 Pages
764-771
Published: September 15, 1977
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A statistical theory of the random ordered phase, proposed by Ueno and Oguchi, in the quenched random mixture with differentsigned exchange interactions is developed further, based on the generalized Bethe approximation. Specially the uniform magnetization in ferro-rich side and the sublattice magnetization in antiferro-rich side are obtained, which cannot be calculated in previous papers.
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Yukio Saito
1977 Volume 43 Issue 3 Pages
772-778
Published: September 15, 1977
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A least principle is derived for Kroemer’s model for the Gunn effect to determine the structure and the velocity of the Gunn domain. Use is made of the reductive perturbation method to treat nonlinear equations of the local electric field. There exist many steady state distributions of the electric field, which are given analytically. The selection of the final field distribution among these steady states are discussed by using a variation functional, which is similar to the free energy functional in equilibrium. The constancy of the applied voltage difference plays an essential role for the formation of domains. The comparison between our formulation and those given by Ridley and by Butcher is made.
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Masahiro Inoue
1977 Volume 43 Issue 3 Pages
779-787
Published: September 15, 1977
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Dynamical behavior of population of excitonic molecules in the kinetic energy space is investigated by taking into account the mutual interaction of molecules and the interaction with the heat bath of acoustic phonons. The potential energy between molecules is assumed to be constant for momentum transfer
q≤
q0 and zero otherwise. Then in the limit of
q0⁄
K→0, where
K is the momentum of the excitonic molecules, the number density in the energy space is described exactly by a Fokker Planck equation. The integral differential equation for the number density is solved numerically and some characteristics of this equation are clarified.
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Bruno Rolov, Vladimir Kuzovkov
1977 Volume 43 Issue 3 Pages
788-792
Published: September 15, 1977
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The effect of polarization fluctuations on the behaviour of acoustic properties of ferroelectrics at second-order phase transition is investigated using the general principles of thermodynamics of irreversible processes. The obtained equations bring out the physical sense of the absorption mechanism: the elastic wave induces polarization, and an essential role in the formation of the electromechanical coupling is played by spatially-heterogeneous polarization fluctuations. There exists a linear relationship between polarization and elastic stress even in the absence of a piezoelectric effect. This mechanism is essential only close to the Curie point. The sound wave propagation, absorption and internal friction coefficients are obtained. The results are in agreement with available experimental data.
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Hideki Yoshizawa, Kinshiro Hirakawa
1977 Volume 43 Issue 3 Pages
793-801
Published: September 15, 1977
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Starting from a viewpoint that melting phenomena are caused by an instability of the lattice vibrations, neutron scattering studies were made on NaF to see how the anharmonic interaction of phonons develops with increasing temperature. The phonon frequency shift and the damping of the [110] TA
1 mode were measured as functions of wave number and frequency over a wide range of temperature from 300 to 1250 K. At temperatures very close to the melting point
Tm=1266 K, high ω(q) phonons are heavily damped, but low ω(q) phonons are still surprisingly stable. A marked frequency softening was observed only for this mode; no evidence for premelting phenomena could be seen, and
Tm appears quite suddenly. It is argued that
Tm will be determined not by the bulk but by the surface potential.
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Toshihide Takagahara, Eiichi Hanamura, Ryogo Kubo
1977 Volume 43 Issue 3 Pages
802-810
Published: September 15, 1977
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A general theory of the intermediate state interaction in the second order optical process is developed by extending the stochastic theory of line shape. We introduce the stochastic models of the intermediate state interaction and discuss the general features of the secondary emission spectrum, focusing particular attention on how the correlation between the incident and the scattered photons are affected by the intermediate state interaction. It is clarified how the spectral features or the relative weights among the various components of the second order optical process are determined by a few physical parameters; the radiative damping rate and the modulation amplitude and rate. Further we discuss the relationships between the first and the second order optical processes.
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Toshihide Takagahara, Eiichi Hanamura, Ryogo Kubo
1977 Volume 43 Issue 3 Pages
811-816
Published: September 15, 1977
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The stochastic theory of intermediate state interaction developed in a preceding paper is applied to more realistic models to discuss the correlation between the incident and the scattered photons in more detail. Through these model calculations it is confirmed that the spectral characteristics of the second order optical process are determined by a few physical parameters of the radiative damping rate and the modulation amplitude and rate. In the slow modulation limit the relative intensity ratio between the broad Raman component and the luminescence is almost determined by the ratio between the radiative damping rate (γ
b) and the modulation rate (γ
m). In the fast modulation limit the ratio between the δ-shaped Raman component if it exists and the luminescence is given by the ratio between γ
b and the dephasing relaxation rate
Δ2⁄γ
m (
Δ denotes the modulation amplitude.).
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Seizo Morita, Nobuo Mikoshiba
1977 Volume 43 Issue 3 Pages
817-821
Published: September 15, 1977
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A simple theory is given for various effects of surface acoustic waves (SAW) on the characteristics of the Josephson effect in tunnel junctions which are narrow with respect to the Josephson penetration depth. We consider the case where a SAW is propagated on the substrate on which the tunnel junction is fabricated. It is shown that new types of steps in the
dc-current-voltage curves of the junction biased with a current source can occur when (1) the phase velocity of the Josephson current density wave matches the velocity of SAW and (2) the phase velocity of the Josephson current density wave modified by SAW matches the phase velocity of tire electromagnetic fields. Possible applications of the new phenomena to (1) a tunable SAW transducers and (2) a tunable generator of submillimeter wave pulses are briefly discussed.
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Shin-ichiro Hatta, Soshin Chikazumi
1977 Volume 43 Issue 3 Pages
822-830
Published: September 15, 1977
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Magnetization curves were measured in high pulsed magnetic fields above 100 kOe for Fe and Ni just below and above their Curie points. For both Fe and Ni, a linear relationship between M
2 and H/M holds in the high field region above 70 kOe. From the linear parts, Landau factors in a phenomenological equation and the critical exponents were determined without being affected by spin clusters. For Fe, the estimated critical exponents are consistent with those expected from the molecular field theory, which are the same results as for Ni. Furthermore, theoretical magnetization curves were calculated by means of the Green function method in order to compare with the experimental results. Both the shapes of calculated curves and their Landau factors are quite similar to the experimental ones.
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Hironori Nishihara
1977 Volume 43 Issue 3 Pages
831-837
Published: September 15, 1977
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Nuclear magnetic resonance of
55Mn of an impurity Mn
2+ spin has been investigated in three metamagnetic phases of CoCl
2·2H
2O at liquid helium temperatures. The hyperfine field at 1.6 K was found to be −594.1±0.3 kOe. A strong temperature dependence of the spin-echo decay time observed at low temperatures indicates that low-lying excitation energies of the Mn
2+ spins are much lower than those of the host Co
2+ spin system. However, there was no temperature dependence of the hyperfine field in the range from 1.6 to 4.2 K, and this was attributed tentatively to the long relaxation time of Mn
2+ spins. When external field was applied parallel to the
b-axis, jumps of the hyperfine field associated with metamagnetic transitions and an anomalous change of the electric field gradient were observed.
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Kengo Adachi, Fumio Kimura
1977 Volume 43 Issue 3 Pages
838-844
Published: September 15, 1977
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Magnetic, electrical and structural properties of Ni (As
xS
1−x)
2 for 0≤
x≤0.5 were investigated experimentally. The magnetic transition points, Néel and Curie points, and the metallic and nonmetallic regions were determined as a function of concentration and temperature. The critical concentration for the magnetic and electrical transitions at absolute zero was given to be
x=0.22. The phase diagram thus obtained can be interpreted qualitatively by the Hubbard model, in which the parameters of transfer integral, Coulombs’ correlation and electron numbers in
eg band are contained. Furthermore, the behavior of electrical resistivity can be explained by the spin fluctuation theory. Finally, a general view of the phase diagram of solid solutions among pyrite type compounds is summarized from the same standpoint.
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Toshihiro Idogaki, Norikiyo Uryû
1977 Volume 43 Issue 3 Pages
845-853
Published: September 15, 1977
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The critical properties of the randomly dilute Ising ferromagnet are discussed for the square lattice by the method of concentration expansion. The studies are mostly limited to the investigation of the effects of the second neighbor interaction on the concentration dependence of the Curie temperature
Tc(
p) and on the temperature dependence of the critical exponent \barγ(θ) describing the susceptibility divergence. The series obtained is analysed by the root, ratio, and Padé approximant methods, respectively. As for
Tc(
p), the previous results are reconfirmed by raising the degree of series expansion. The present calculation gives an apparent temperature dependence of \barγ(θ) and its behavior can be compared with the results previously calculated for some three-dimensional lattices. Furthermore, it is found that the essential feature of \barγ(θ) is not affected by the presence of the second neighbor interaction.
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Hiroki Itoh, Kiyosi Motida, Syôhei Miyahara
1977 Volume 43 Issue 3 Pages
854-856
Published: September 15, 1977
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Magnetization and susceptibility measurements were made on polycrystalline samples of Zn
1−xNi
xCr
2S
4 from 4.2 K to 800 K in magnetic fields up to 16.5 kOe. The inverse susceptibilities except for ZnCr
2S
4 show a non-linear behavior characteristic of a ferrimagnet. This indicates that the system has a magnetic moment on Ni
2+ in contrast with NiRh
2S
4 and the sign of Ni
2+–Cr
3+ exchange interaction is negative. The saturation magnetization of the sample (x=0.40) is equal to 3.0±0.1 μ
B/molecule at 4.2 K. Electrical resistivity of the sample (x=0.40) was measured between 77 K and 300 K, and it is semiconducting (3×10
3Ω cm at R. T.).
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Kazukiyo Nagata, Ikuo Yamamoto, Hideo Takano, Yasaburo Yokozawa
1977 Volume 43 Issue 3 Pages
857-861
Published: September 15, 1977
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This paper reports the experimental and theoretical study on the temperature dependence of the electron paramagnetic resonance (EPR) field at fixed frequency in a quadratic layer antiferromagnet k
2MnF
4. The shift of EPR field (or EPR g-shift) from the value in the infinite temperature limit is theoretically shown to be a function of the parallel and perpendicular susceptibilities. The predictions of the theory are compared with the results of EPR and torque measurements performed on the single crystal of K
2MnF
4 at temperatures above the Néel point. Excellent agreement is obtained.
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Hiroshi Yoshie
1977 Volume 43 Issue 3 Pages
862-868
Published: September 15, 1977
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The nuclear magnetic resonances of the Co
59 in Y
1−xDy
xCo
5 at 77 K and Y
1−xHo
xCo
5 at 293 K have been observed for 0≤
x≤0.5 and
x=1. It is found that the contribution of 4f electrons to the hyperfine field at the cobalt nucleus,
H4f, is at most 3 kOe for DyCo
5 and nearly zero for HoCo
5. These values are given by
H4f=6[(
gJ−1)
J−2]. The nuclear magnetic resonances of the Co
59 in Y
1−xGd
xCo
2 for 0.3≤
x≤1, YCo
3 and Y
2Co
7 have also been observed at 77 K. The hyperfine fields at the Co
59 in YCo
3, Y
2Co
7, YCo
5 and Y
2Co
17 are interpreted by assuming that the hyperfine fields in these compounds are the sum of two contributions; one is proportional to the cobalt magnetic moment and the other is proportional to the number of the s-charactered conduction electrons per cobalt atom, which are supplied from the yttrium atoms.
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Takao Suzuki
1977 Volume 43 Issue 3 Pages
869-874
Published: September 15, 1977
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Thermal expansivities of Cr–Si alloys containing small amounts of Si up to 2.0 at.% were measured above 100 K. For alloys with Si atoms ranging from 1.0 to 1.4 at.%, two first order transitions are observed successively for the transitions from the paramagnetic (P) state to a commensurate (C) spin density wave (SDW) state and from the CSDW to an incommensurate (I) SDW state with decreasing temperature. The tricritical point is assigned to T
N*=245 K and C
*=0.975 at.% Si, where three loci of the P–I, P–C and C–I transitions concurred together satisfying the condition of the second order transition. On the basis of the two band model, just one of the four outer electrons of Si is estimated to flow into the magnetic bands of Cr.
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Yoshihiro Ohmura, Hisatake Sano
1977 Volume 43 Issue 3 Pages
875-884
Published: September 15, 1977
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The exponents at the threshold of soft X-ray absorption and emission spectra of metals in the theory of Nozières and De Dominicis are calculated. Effects of the periodic potential on an electron in a conduction band are formulated to be given in an effective mass approximation and the structures of the inner-shell holes are included in the hole potentials. In the present formulation, the change of the electronic wave function in metals due to the hole potential is expressible in terms of the phase shift which is obtained in the first Born approximation. The exponents obtained in this way give a satisfactory agreement with the experiments on the absorption and emission spectra of Na, Mg and Al within the precision of analysis. In particular, for Li our result agrees roughly with the experimental one obtained by Baer
et al. (Phys. Rev. Letters
37 (1976) 49) using X-ray photoemission.
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S. P. Srivastava, R. C. Srivastava, I. D. Singh, S. D. Pandey, P. L. G ...
1977 Volume 43 Issue 3 Pages
885-890
Published: September 15, 1977
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The lattice parameter of NiO from 105 K to 813 K has been measured using the X-ray diffraction technique. An orthogonal polynomial of second-order with least square error approximation is fitted to the lattice parameter versus temperature data to obtain the thermal expansion coefficient, α. The high temperature values of α have been found to be in close agreement with the measurements of earlier workers, using an automatic recording dialatometer.
Experimental investigations have also been made of the infrared transmission spectrum of NiO in the region of fundamental lattice absorption between 293 K and 500 K, using a Beckman IR-12 spectrophotometer. The shift in the long-wavelength optical mode frequency with temperature is discussed in terms of volume and other anharmonic effects employing the present values of α and is found to agree qualitatively with the theory of Maradudin and Fein.
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Kenichiro Takahei, Koichi Kobayashi
1977 Volume 43 Issue 3 Pages
891-898
Published: September 15, 1977
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The optical constants of TlCl–TlBr mixed crystals are determined in the region of 2.8 to 6.0 eV from the measurements of normal incidence reflectivity as well as refractive index at helium temperature. As the composition changes, the lowest direct exciton peak shifts continuously with downward bending, while both the second and the third absorption peaks do not continue from TlCl to TlBr. The fourth peak is found to shift smoothly, but with upward bending. These phenomena are explained in relation to the band structures and the theory of electronic states of mixed system developed by Onodera and Toyozawa.
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Koichi Shindo, Hisashi Nara
1977 Volume 43 Issue 3 Pages
899-902
Published: September 15, 1977
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The microscopic inverse dielectric matrix in the limit of a long wavelength is calculated in the random phase approximation for Si and Ge by using the realistic band models. It is shown that, if a proper form of the pseudopotential is employed, the acoustic sum rule can be substantially satisfied without any adjustable parameter, and the local field correction to the static dielectric constant can not be neglected.
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Masasi Inoue, Kiyoaki Ishii, Hisao Yagi
1977 Volume 43 Issue 3 Pages
903-906
Published: September 15, 1977
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Using a superconducting solenoid attainable up to 40 kG, measurements have been made of the transverse magnetoresistance and Hall voltages in the Mn-doped (0.88 and 2.2 at.%) SnTe crystals at liquid helium temperatures. The magnetic impurity spins align ferromagnetically below certain temperature
Tm, around which the magnetoresistance becomes negative. The observed Hall effect consists of the normal temperature-independent component
R0 and the extraordinary component
R1 which appears only below
Tm. A graphically estimated saturation magnetization obeys approximately the Bloch
T3⁄2 law, which clearly shows the presence of ferromagmetism in this Mn-doped degenerate semiconductor.
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Fusayoshi J. Ohkawa, Yasutada Uemura
1977 Volume 43 Issue 3 Pages
907-916
Published: September 15, 1977
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The theories based upon the multi-valley effective mass equation proposed by Twose are criticized and it is concluded that they can not explain the observed valley splittings. In order to treat valley splittings correctly, a formulation based upon the extended zone scheme is presented with the main interest in the valley splitting in an
n-channel (100) inversion layer of Si.
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Fusayoshi J. Ohkawa, Yasutada Uemura
1977 Volume 43 Issue 3 Pages
917-924
Published: September 15, 1977
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The extended zone effective mass equation as proposed in the preceding paper is applied to the vally splitting in an
n-channel (100) inversion layer of Si, and the valley splitting is explained theoretically for the first time. The splitting turns out to be about
ΔE=0.15×(
Ninv+32⁄11
Ndepl) meV for the carrier concentrations
Ninv and
Ndepl of the inversion and depletion layers which are in 10
12 cm
−2 unit. The mechanism of the splitting is the electric break through, and two kinds of break through play a role in this system. The estimated splitting is too small to be observed, and it is suggested that the splitting will be greatly enhanced by many-body effects under a high magnetic field. However the appearance of the characteristic cusps in the measured line shapes of the Schubnikov-de Haas oscillation confirms that the theory gives the correct magnitude of the valley splitting without the enhancement by many-body effects.
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Fusayoshi J. Ohkawa, Yasutada Uemura
1977 Volume 43 Issue 3 Pages
925-932
Published: September 15, 1977
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The enhancement of the valley and spin splittings in the presence of a high magnetic field in an
n-channel (100) inversion layer of Si by a screened exchange interaction are investigated theoretically. The splittings are enhanced enough to be observed in the experiments. The line shapes of the Schubnikov-de Haas oscillation are also calculated, and the results agree with the experiments including the appearance of cusps in the line shapes. The many-body theory can not only explain the observed splittings but also confirm the one-body theory of the valley splitting presented by the present authors.
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Toshio Osaka, Yasuharu Makita, Kazuo Gesi
1977 Volume 43 Issue 3 Pages
933-936
Published: September 15, 1977
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The dielectric properties of deuterated triammonium deuterium disulfate have been studied at 1 atm in the temperature region between −170°C and 25°C. It has been found that the crystal is ferroelectric in two phases. The spontaneous polarization is 2.15 μCoul·cm
−2 at −170°C. The present results indicate a large isotope effect on ferroelectric activity.
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Hiroshi Kajikawa, Toru Ozaki, Eiji Nakamura
1977 Volume 43 Issue 3 Pages
937-941
Published: September 15, 1977
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Measurements of the spontaneous polarization are made for RbHSO
4. The results in the temperature range 0.1°C<
T0−
T<100°C are well explained by using the elastic Gibbs function of
G1−
G10=(1⁄2)χ
P2+(1⁄4)ξ
P4+(1⁄6)ζ
P6 and χ=(4π⁄
C)(
T−
T0) with
T0=−8°C,
C=144°C, ξ=7.2×10
14 Jm
5C
−4 and ζ=4.2×10
19 Jm
9C
−6. The value of δ defined by
P∝
E1⁄δ at
T0 is obtained to be 3, the mean field value, in the range
E≥∼200 V/cm.
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Katsumi Hamano, Kenji Ema, Toshihisa Yamaguchi
1977 Volume 43 Issue 3 Pages
942-949
Published: September 15, 1977
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The static and dynamic electrostrictive properties of order-disorder type ferroelectrics are discussed. The theory takes into account properly the role of an ionic polarization which interacts with a dipole system. The electrostrictive constants
M and
Q with which the electrostrictive contribution to the total strain is written as
ME2 or
QP2 are calculated. The constant
M diverges when
TC is approached from above as well as from below, its sign below
TC being opposite to that above
TC. The constant
Q shows a marked temperature dependence in the ferroelectric phase. Besides, it shows a sharp cusp at
TC when the Curie constant is small. The electrostrictive strain under an alternating electric field is expected to show an anomalous phase lag. All these are due to the dielectric nonlinearity and/or the presence of an ionic polarization. When the ionic polarization is ignored, the result reduces to that of Landau-Devonshire theory.
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Mitsuo Wada, Akikatsu Sawada, Yoshihiro Ishibashi, Yutaka Takagi
1977 Volume 43 Issue 3 Pages
950-953
Published: September 15, 1977
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Raman spectra of (NH
4)
2BeF
4 in the frequency range from 0 to 200 cm
−1 were measured from room temperature to the liquid nitrogen temperature, including the phase transition points
T1 (183 K) and
T2 (177 K). No soft-mode was observed in this temperature range. There are several lines belonging to the
A1 and
B2 irreducible representations which were observed only in the phase III.
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R. P. Gairola, B. S. Semwal
1977 Volume 43 Issue 3 Pages
954-960
Published: September 15, 1977
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An expression is obtained for the thermal conductivity of a displacive ferroelectrics in paraelectric phase, in presence of an external electric field, using Kubo formalism and double time Green’s function technique. The total thermal conductivity which is the sum of two terms contributed by optical and acoustical phonons respectively, is seen to increase with the applied field, in agreement with the experimental results of Steigmeier. In the absence of an external field, the expression reduces to the Carruther’s formula giving the temperature dependence of the thermal conductivity. In the vicinity of the Curie temperature, the thermal conductivity shows anomalous behaviour.
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Yutaka Iwata
1977 Volume 43 Issue 3 Pages
961-967
Published: September 15, 1977
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The structure of paraelectric phase of Pb
5Ge
3O
11 was refined by the least squares calculations of single crystal neutron diffraction data at 200°C. Final R value was 0.08 and the type of phase transition was determined as displacive one. The existence of unstable oxygen atom which is lying on the mirror plane perpendicular to the
c-axis was found to have relation with the reorientation of GeO
4 group. Atomic displacements through the phase transition were evaluated and used for the calculation of the spontaneous polarization for the point charge model. This gave P
s to be 2.0 μC/cm
2, a smaller value than the observed one of 4.2 μC/cm
2 at room temperature.
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Akira Takahashi
1977 Volume 43 Issue 3 Pages
968-975
Published: September 15, 1977
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The following formula of the quadrupolar relaxation rate 1⁄
T1Q of
27Al in water is derived by considering that the configuration of the water molecules in the first layer around the Al
+++ ion is randomly altered between the symmetries T
h and C
2v:
(
Remark: Graphics omitted.)
where
eq is the maximum value of the field gradient component along a principal axis at the nucleus,
W0 and
W are the probabilities per unit time for the symmetry of the configuration to change from T
h to C
2v or in the reverse direction respectively, and τ
cR is the correlation time for the rotational diffusion of the hydration complex.
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Akira Takahashi
1977 Volume 43 Issue 3 Pages
976-984
Published: September 15, 1977
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The probabilities per unit time for the configuration of the first layer water molecules co-ordinated to Al
+++ in AlCl
3 aqueous solution to jump from the T
h symmetry to the C
2v, symmetry or in the reverse direction are determind semi-empirically, and the quadrupolar relaxation rate of
27Al is calculated. The result is in good agreement with the experimental value. The existence of an inertia effect in the relaxation mechanism is also proved.
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Yoshirou Sakagami, Sho Yoshida
1977 Volume 43 Issue 3 Pages
985-992
Published: September 15, 1977
Released on J-STAGE: June 01, 2007
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The influence of an impurity atom on the formation process of secondary defects has been presented from a kinetic point of view. A random motion of vacancies is described by the theory of stochastic processes and the transition probabilities are constructed in taking account of crystal structures. The unified point of view for the passage time of vacancies and the lifetime of the complex can be obtained by the concept of the mean first passage time in probability theory and this makes it possible to discuss the existence condition of the complex. In actual calculations, the lattice points are grouped into the shells around an impurity atom and the calculations are performed for two cases of aluminum, in each of which the range of the impurity-vacancy interaction extends to the 1st shell, and to the 2nd shell.
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Akizo Okuda, Tadahiko Harami, Takeyuki Okada, Yoshito Tanaka, Osamu Ta ...
1977 Volume 43 Issue 3 Pages
993-998
Published: September 15, 1977
Released on J-STAGE: May 29, 2007
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Optical and thermal bleaching of the
V2 and
V3 bands were investigated for additively- or electrolytically-colored KI crystals. After
V3-light irradiation at 85 K, absorption bands were formed at 430 and 800 nm in company with an increase near the fundamental-absorption edge; while, after the same irradiation at 125 K, the α band and a band with a peak at about 330 nm were formed simultaneously. Changes in intensities among these bands were caused with subsequent optical or thermal treatments; changes in the
V2 and
V3 bands were always accompanied. Upon irradiation with polarized light, the band at about 330 nm exhibited the [100] anisotropy, whose maximum was shifted to 325 nm. On the assumption that cation vacancies are introduced in halogen-excess crystals, probable models of
V centers are discussed and then the photochemical and thermal changes are interpreted by them.
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Hideo Sakairi, Eiichi Yagi, Akio Koyama, Takashi Karasawa, Ryukiti R. ...
1977 Volume 43 Issue 3 Pages
999-1005
Published: September 15, 1977
Released on J-STAGE: June 01, 2007
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The irradiation of copper was performed at liquid helium temperature with charged particles, p, α, and carbon ions, from a cyclotron and the increase of electrical resistivity was measured. The ratio of the theoretical resistivity increase evaluated with the Kinchin-Pease model to the experimental one was 3.0 common to three particles, which was smaller by about 20% than that derived from an existing data on deuteron irradiation. The correction for ionization loss made that ratio decrease to 2.5 and the use of the Robinson-Torrens model which contains the direct recombination mechanism, made it decrease to 2.0. This value is quite the same as that for neutron irradiation. The effect of direct recombination adopted in the Robinson-Torrens model is not so drastic in reducing the theoretical value.
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Hideaki Koike
1977 Volume 43 Issue 3 Pages
1006-1012
Published: September 15, 1977
Released on J-STAGE: June 01, 2007
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The dielectric constants of Ag-based alloys with a small amount of Zr, Nb and Mo are evaluated from measurements of reflectances and transmittances of thin films prepared by simultaneous evaporation in vacuum for photon energies between 0.55 eV to 5.63 eV. The dc resistivities and the thermoelectric powers of the films are also measured. An additional absorption band due to the presence of the virtual bound state is observed for all alloy systems. The data are compared with the calculation based on the Friedel-Anderson model. The positions of the virtual bound states of the alloys are estimated.
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Keiichi Kaneto, Katsumi Yoshino, Yoshio Inuishi
1977 Volume 43 Issue 3 Pages
1013-1015
Published: September 15, 1977
Released on J-STAGE: May 29, 2007
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The plasma edge around 2.7 eV in the reflectance spectrum of (SN)
x single crystal for
E⁄⁄
b-axis polarization shows the blue shift with lowering temperature. The relaxation time of the free electron estimated from the reflectance spectrum at 4.2 K is slightly larger than that of 300 K by the factor of 1.5, resulting in the much smaller temperature dependence of the σ
opt (conductivity at optical frequency) compared with that of σ
dc (conductivity at dc). Several models which explain these results are discussed.
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Noboro Yamada, Shoichi Kawano
1977 Volume 43 Issue 3 Pages
1016-1020
Published: September 15, 1977
Released on J-STAGE: June 01, 2007
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An X-ray study has been made for Rb
2Cd
2(SO
4)
3 crystals and the superlattice reflections are found in both ferroelectric phases. The crystal symmetries of the two ferroelectric phases were determined to be monoclinic C
22(P2
1) and triclinic C
11(P1) as the temperature was decreased. The lattice parameters were measured as a function of temperature by the Bond method. The cell parameters are determined without consideration of the superlattice structure as a=10.3482±0.0005Å, b=10.3430±0.0005Å, c=10.3475±0.0005Å, β=90.04±0.006° and α=γ=90±0.006° at −150°C, and a=10.3392±0.0005Å, b=10.3330±0.0005Å, c=10.3382±0.0005Å, β=90.038±0.006°, α=89.988±0.006° and γ=89.979±0.006° at −190°C. The phase transition
T4–C
22 is accompanied by the lattice modulations of two types the periods of which are 2 times and 3 times the spacing.
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Nobuaki Noda
1977 Volume 43 Issue 3 Pages
1021-1026
Published: September 15, 1977
Released on J-STAGE: May 29, 2007
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The cross sections for electron stripping of hydrogen molecules have been measured at the energies ranging from 0.2 keV to 5.0 keV. The measured cross section varies from 1.1×10
−18 cm
2 to 8.0×10
−17 cm
2 for the target of H
2 and from 2.2×10
−18 cm
2 to 2.6×10
−16 cm
2 for that of N
2. In lower energies, the cross sections for H
2–H
2 collision give remarkably smaller values than those by Peterson
et al. which were obtained using the large effective angle (∼10°) in contrast to the small one (∼1°) in the present experiment. This suggests that the differential stripping cross sections are fairly large at scattering angles larger than 1 degree in the energies below 1 keV.
Present cross sections will be recommended to be used for analysis in the plasma diagnostics with H
2 molecules using the apparatus with the small effective angle.
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Kuninori Sato
1977 Volume 43 Issue 3 Pages
1027-1033
Published: September 15, 1977
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Leading members of the Lyman series of He II emitted from a high-density helium plasma have been measured by the use of the Rare-gas Photoelectron Counter which is based on the energy analysis of photoelectrons liberated by XUV radiation. Stationary population inversion between low lying levels of He
+ is confirmed in a recombining plasma which is interacting with neutral helium. The ratio
n2⁄
g2 :
n3⁄
g3 :
n4⁄
g4 :
n5⁄
g5 is found to be 1 : 0.6 : 1.1 : 1.2. A method of determining the electron temperature, the electron density and the ion density from the recombination continua is described. Collisional and recombination processes can explain reasonably the observed level populations.
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Keiichiro Yamagiwa
1977 Volume 43 Issue 3 Pages
1034-1041
Published: September 15, 1977
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Using a coaxial double-plasma device of a new type, we excited lower hybrid waves propagating almost perpendicularly to the magnetic field. The dispersion relation of the excited waves agree well with the theoretical value obtained with the warm plasma approximation. These waves were mainly subject to the ion Landau damping, and then the ion energy efficiently increased in the direction perpendicular to the magnetic field.
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Toshio Okada, Takashi Yabe, Keishiro Niu
1977 Volume 43 Issue 3 Pages
1042-1047
Published: September 15, 1977
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Spontaneous generation of propagating electromagnetic fields due to a microinstability is investigated for plasmas which convey electron thermal fluxes. The following two cases are examined: 1) Electromagnetic fields spontaneously excited by electrons in a velocity distribution of skewed Maxwellian type. 2) Electromagnetic waves generated by electrons in a velocity distribution which consists of a main part and a high energy part. In this case, the electron thermal flux can be very high. In both cases, induced electromagnetic waves with relatively low frequencies propagate parallel to the direction of Thermal flux.
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Kaoru Ohya, Ichiro Mori
1977 Volume 43 Issue 3 Pages
1048-1053
Published: September 15, 1977
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The stopping power of plasma for beam electrons was measured by using two different ways. One way was based on the variation of energy spectrum of beam electrons due to the interaction with the plasma and the other was based on the decrease of beam current reaching the collector due to the interaction with the plasma. The value obtained is explained by using quasi-linear equations with frequency spectrum of waves observed experimentally.
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Shinsuke Watanabe
1977 Volume 43 Issue 3 Pages
1054-1059
Published: September 15, 1977
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Effect of dissipation on the formation of ion acoustic solitons is investigated by experiments and by numerical calculations. In the experiments, a large amplitude initial perturbation does not evolve into solitons, but into a triangular wave with ripples on a leg when a neutral gas pressure is increased or when a random low frequency noise is superposed. Numerical analyses of the K-dV equation with dissipation terms show that an initial perturbation develops into a triangular wave when the dissipation depends on the wavenumber. Therefore the formation of the triangular wave in the experiment is not due to an increase of collisional damping, but to an increase of collusionless dissipation, i.e. Landau damping resulting from a decrease of the temperature ratio between the electrons and ions.
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Hiromichi Ezumi, Masahiko Kawamura, Toshiaki Yokota
1977 Volume 43 Issue 3 Pages
1060-1067
Published: September 15, 1977
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The ionization relaxation processes behind shock waves in pure krypton and krypton-argon mixtures have been investigated using a Mach-Zehnder interferometer technique. The incident shock velocity was fixed in the neighborhood of Us=2800 m/sec, and the initial pressure was fixed at 0.95 Torr. The experimental results were compared with theoretical values based on the two-step collisional ionization model taking into account of the wall boundary-layer effect. The slope constants of excitation cross section against relative kinetic energy between krypton atom-atom collisions, krypton atom-electron collisions, and krypton-argon atom - atom collisions were determined to be 4.2×10
−19 cm
2/eV, 1.2×10
−17 cm
2/eV, and 4.2×10
−19 cm
2/eV, respectively.
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Yoshiyuki Furuya
1977 Volume 43 Issue 3 Pages
1068-1073
Published: September 15, 1977
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On the basis of the variational formulation of thermoelasticity, a melting problem of an elastic solid is discussed. Two variational invariants of thermoelasticity with phase change are introduced and a variational equation is formulated. The method is entirely variational and does not require the evaluation of the temperature field. A parabolic approximation of temperature field is used as a test function and an approximate differential equation of the melting line is formulated. Using Adams-Bashforth’s method this equation provides a series solution.
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