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1.
V. V. Vysotskii 《Physics of the Solid State》1997,39(5):718-721
Within the framework of the diffusion approximation for the dynamic magnetic flux, a model is constructed for the dynamic
magnetic susceptibility of a superconductor with a nonuniform and time-dependent magnetic field distribution in the sample.
The possibility of appearance of peaks in the temperature (or frequency) dependence of χ″ in a structurally homogeneous superconducting sample in the presence of a magnetic-field-induced nonuniformity of the diffusion
parameter is demonstrated. The character of the temporal evolution of the magnetic susceptibility during relaxation of the
magnetic moment of the sample is predicted and its properties are investigated.
Fiz. Tverd. Tela (St. Petersburg) 39, 811–815 (May 1997) 相似文献
2.
N. D. Naumov 《Technical Physics》1998,43(1):93-96
A self-similarity approach is used to obtain envelope equations for an annular beam propagating along a magnetic field, and
also an electron beam injected at an angle to a magnetic field. An exact solution is constructed for the self-consistent problem
of transverse oscillations of a cold annular beam in a magnetic field, and a comparison is made with approximate results from
the method of envelope equations.
Zh. Tekh. Fiz. 68, 103–107 (January 1998) 相似文献
3.
We study the linear response of a system of single-domain ferromagnetic particles with cubic magnetic anisotropy to a weak
external a.c. magnetic field. By averaging the Gilbert equation with a fluctuating field for the magnetization of an individual
particle we derive a system of recurrence equations for the spectra of equilibrium correlation functions describing the longitudinal
relaxation of the system. We find the solution of this system by using matrix continued fractions. We also evaluate the longitudinal
relaxation time and the spectrum of the complex-valued magnetic susceptibility. Finally, we show that the nature of susceptibility
dispersion is determined by the anisotropy and dissipation parameters.
Zh. éksp. Teor. Fiz. 115, 101–114 (January 1999) 相似文献
4.
An analytical model and equations for describing the field of a planar magnetic lens with two concentric nonmagnetic gaps
are developed. It is demonstrated that the “half-width” of the magnetic field of the lens can be controlled by varying independently
the currents in the excitation coils of the two gaps. This makes it possible to control the focal length and the spherical
aberration of the lens. It is shown that when oppositely directed currents are used in the excitation coils, a planar magnetic
lens that does not rotate the image can be obtained.
Zh. Tekh. Fiz. 69, 133–134 (August 1999) 相似文献
5.
A contactless microwave method is used to measure the fast magnetic relaxation of granular ceramic samples of YBa2Cu3O7−x
irradiated by neutrons with fluences of 1016–1019 cm−2. An experimental study of the time dependence of the relaxation of high-frequency (rf) absorption (f=100 MHz) after the action of an external magnetic field pulse has shown the magnetic relaxation times τ
0 to be in the time interval of 0.5–150 ms. The rf-absorption mechanism is discussed in terms of an intergranular system with
a thermally activated flux of vortices and their diffusion in the granular medium.
Fiz. Tverd. Tela (St. Petersburg) 39, 977–981 (June 1997) 相似文献
6.
O. V. Volkov 《Physics of the Solid State》1998,40(6):1019-1027
An efficient method is proposed for the self-consistent calculation of Landau levels of a quasi-two-dimensional hole gas at
a GaAs/AlGaAs heterostructure in a perpendicular magnetic field. The method is based on transforming the Schroedinger and
Poisson equations to a system of nonlinear differential equations which are then spatially discretized and solved by the method
of relaxation. The method proposed is used to model the optical spectra for recombination of the quasi-two-dimensional hole
gas with electrons localized at a dlayer of donors in an isolated p-type heterojunction. Particular attention is paid to effects associated with the dependence of the wave functions and shape
of the potential well on the magnetic field, which have not been considered before.
Fiz. Tverd. Tela (St. Petersburg) 40, 1117–1125 (June 1998) 相似文献
7.
Yu. I. Golovin R. B. Morgunov A. A. Baskakov S. Z. Shmurak 《Physics of the Solid State》1999,41(11):1783-1785
After exposure of single-crystal ZnS with microscopic twinning to magnetic fields of 1–10 T, the integral electroluminescence
brightness is found to increase by several times. It is proposed that the magnetic field facilitates relaxation of a metastable
state of the structural defects.
Fiz. Tverd. Tela (St. Petersburg) 41, 1944–1947 (November 1999) 相似文献
8.
Kh. K. Aliev I. K. Kamilov Kh. I. Magomedgadzhiev M. -G. K. Omarov 《Physics of the Solid State》1997,39(2):296-297
The absorption coefficient α
k for longitudinal ultrasonic (15 MHz) waves propagating transverse to the direction of a magnetic field H is measured in single crystal gadolinium. It is found that in fields H⩽600 Oe, the peak in α
k is shifted toward lower temperatures, while the absolute magnitude of the absorption rises with increasing H. It is shown on the basis of dynamic scaling that the anomalous behavior of α
k in fields H⩽600 Oe can be explained by introducing a magnetic field analog of the Landau-Khalatnikov relaxation mechanism.
Fiz. Tverd. Tela (St. Petersburg) 39, 339–340 (February 1997) 相似文献
9.
Yu. I. Golovin R. B. Morgunov A. A. Baskakov M. V. Badylevich S. Z. Shmurak 《JETP Letters》1999,69(2):127-132
It is found that a ∼10 T magnetic field influences the microhardness and the photo-and electroluminescence of ZnS single crystals
containing microtwins. It is established that a magnetic field irreversibly changes the properties of the crystal, leading
to relaxation of the metastable states of structural defects.
Pis’ma Zh. éksp. Teor. Fiz. 69, No. 2, 114–118 (25 January 1999) 相似文献
10.
V. M. Korovin 《Technical Physics》1999,44(10):1141-1149
A linear partial differential equation describing the evolution of an initial disturbance of a flat free surface of a thin
layer of a viscous magnetic fluid covering a horizontal plate in the presence of a uniform magnetic field, is derived within
a system of ferrohydrodynamic and magnetostatic equations. The effect of magnetizing the plate on the stability of the flat
free surface is investigated. An estimate is obtained for the minimum value of the tangential component of the magnetization
vector of the fluid sufficient to radically alter the pattern of the final breakup of the continuous layer.
Zh. Tekh. Fiz. 69, 14–22 (October 1999) 相似文献
11.
Yu. I. Golovin R. B. Morgunov S. E. Zhulikov V. A. Kiperman D. A. Lopatin 《Physics of the Solid State》1997,39(4):554-558
This paper presents the results of an investigation into the effect of a pulsed magnetic field on the state of linear and
point defects in ionic crystals. For different amplitudes (1–7 T) and pulse lengths (3×10−5 to 102 s) of the pulsed field the kinetics of the transformation of defects into a new state and their relaxation after the field
is turned off are studied in the temperature range 77–400 K. It is found that the relaxation of the states of point defects
is mainly through recombination, and the change of state of the dislocations and of the point defects contribute nonadditively
to the change in the dislocation mobility. The exposure of the crystal to a magnetic field leads to an increase in the dislocation
mobility when the sample is mechanically stressed and to a decrease in the dislocation displacement with a second field pulse.
Fiz. Tverd. Tela (St. Petersburg) 39, 634–639 (April 1997) 相似文献
12.
13.
The possibility of resonance during elastic intravalley scattering in n-type semiconductors is investigated in connection with the crossing (due to anisotropy of the effective mass) of the energy
levels of excited states of a shallow donor as functions of the magnetic field. The hybridization of states of different frequencies
in the vicinity of a crossing is attributed to the emergence of a nonzero dipole moment of the excited impurity atom and,
accordingly, a long-range potential, which creates carrier-transport anomalies. The lower part of the donor spectrum is calculated
as a function of the magnetic field in Si with B∥〈001〉 and in Ge with B∥〈111〉 or B∥〈110〉. A crossing occurs in Ge in the field range 9.9 T<B<16.7 T and in Si in the field range 10.5 T<B<37.7 T. The characteristic longitudinal relaxation time and the transverse conductivity, which are determined by scattering
at excited donors in the presence of the hybridization of states, are calculated.
Zh. éksp. Teor. Fiz. 112, 975–1010 (September 1997) 相似文献
14.
The results of an experimental and theoretical investigation of strong turbulence produced by an external rf field in the
plasma of a beam-plasma discharge are presented. The modulation instability of a rf electric field, perpendicular to a constant
magnetic field, in the frequency range between the lower-hybrid and ionic Langmuir frequencies, has been investigated. It
is shown that the low-frequency fields can be used to control beam relaxation.
Pis’ma Zh. éksp. Teor. Fiz. 64, No. 9, 608–612 (10 November 1996) 相似文献
15.
V. S. Popov B. M. Karnakov V. D. Mur 《Journal of Experimental and Theoretical Physics》1998,86(5):860-874
A semiclassical theory is developed for the ionization of atoms and negative ions in constant, uniform electric and magnetic
fields, including the Coulomb interaction between the electron and the atomic core during tunneling. The case of crossed fields
(Lorentz ionization) is examined specially, as well as the limit of a strong magnetic field. Analytic equations are derived
for arbitrary fields ℰ and ℋ that are weak compared to the characteristic intraatomic fields. The major results of this paper
are obtained using the “imaginary time” method (ITM), in which tunneling is described using the classical equations of motion
but with purely imaginary “time.” The possibility of generalizing the ITM to the relativistic case, as well as to states with
nonzero angular momentum, is pointed out.
Zh. éksp. Teor. Fiz. 113, 1579–1605 (May 1998) 相似文献
16.
V. G. Peschanskii 《Journal of Experimental and Theoretical Physics》1998,87(2):369-374
The propagation of electromagnetic waves in organic layered conductors with metallic conductance and a quasi-two-dimensional
electron energy spectrum of arbitrary form is studied theoretically. The depth of penetration of the electromagnetic field
into the conductor is found, and it is discovered to be sensitive to the polarization of the incident wave. This is done for
an arbitrarily oriented (with respect to the layers) magnetic field so strong that the radius of curvature of the electron
path is much smaller than the electron’s mean free path. It is established that studying these effects in experiments can
reveal in detail the shape and dimensions of the Fermi surface and the relaxation properties of the conduction electrons.
Zh. éksp. Teor. Fiz. 114, 676–686 (August 1998) 相似文献
17.
We solve the equations for the collisionless spin dynamics of a normal Fermi liquid, which describe structures resembling
spin vortices coherently precessing in a uniform magnetic field. We examine their stability and relaxation, and consider various
regimes of stationary magnetization transport along a channel.
Zh. éksp. Teor. Fiz. 114, 1266–1283 (October 1998) 相似文献
18.
I. F. Voloshin A. V. Kalinov S. E. Savel’ev L. M. Fisher V. A. Yampolskii F. Perez Rodriguez 《Journal of Experimental and Theoretical Physics》1997,84(3):592-598
A model systematically accounting for the cutting of Abrikosov flux lines has been developed for the critical state of a hard
superconductor in crossed dc and ac magnetic fields. The electrodynamic equations have been derived by minimizing the Gibbs
free energy calculated using the proposed two-velocity hydrodynamic model. One velocity describes the motion of the vortex
lattice as a whole, and the other describes the relative motion of the two intersecting sublattices. The resulting equations
yield as special cases the previously known electrodynamic equations for hard superconductors. The model provides a natural
explanation for the suppression of dc magnetization by a transverse ac magnetic field observed in our experiments.
Zh. éksp. Teor. Fiz. 111, 1071–1084 (March 1997) 相似文献
19.
E. M. Boldyrev 《Technical Physics》1997,42(2):206-211
The solutions of the equations of motion of a charged particle in an external electromagnetic field consisting of a superposition
of a constant uniform magnetic field and the field of a circularly polarized electromagnetic plane wave are presented as solutions
of the Cauchy problem. The resonance case is studied.
Zh. Tekh. Fiz. 67, 94–99 (February 1997) 相似文献
20.
T. Kondow A. Matsushita K. Kuchitsu K. Nishiyama Y. Morozumi K. Nagamine 《Hyperfine Interactions》1986,32(1-4):807-812
Surface muons produced in UT-MSL were introduced into argon gas of 4.0±0.2 atm with NO2 (0–30 ppm), and muonium signals were detected in the presence of a transverse (1.7–3.4 G) and a longitudinal magnetic field
(0–3.5 kG) at 295±1 K. The cross section for the transverse relaxation was (11.0±1.0)×10−16 cm2. The relaxation rates in different longitudinal magnetic fields show that the rate does not follow the conventional equation
which assumes that the relaxation occurs mainly by spin-exchange interaction. Similar measurements were performed for the
Mu+O2 system. These findings indicate that chemical reactions contribute to these relaxation rates. 相似文献