摘要:

Comparative analysis of the results of measurements of soft magnetic resonant modes in weak ferromagnets with different temperatures of spontaneous reorientation is carried out. It is shown that the longitudinal oscillations of magnetization make a contribution to the energy gap even in zero magnetic field (in the case of spontaneous reorientation) and increases with increasing temperature alone. ©1998 American Institute of Physics.

ISSN:1063-777X    

DOI:10.1063/1.593576

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The thermal conductivity&lgr;(x=0,0.15,0.3,0.6;T=2–200 K) and electrical resistivity&rgr;(0⩽x⩽0.5;T=6–300 K) of layered crystalsNb1−xSnxSe2are measured in theabplane. The metal– semiconductor transition is observed atx≈0.5. The magnitude of the resistivity anomaly observed at 33 K and associated with a transition to the charge density wave phase increases with increasingxforx>0.15. The thermal conductivity of the metallic samples(x<0.5)increases with temperature atT>90K, which is in accord with the nonlinearity of the&rgr;(T)dependence. The absence of such an increase in&lgr;(T)for a semiconducting sample indicates that this singularity is connected with the electronic subsystem. The observed nonmonotonicity of the&rgr;(x)dependence may be associated with the existence of a sharp peak in the electron density of states near the Fermi level. Approximation of the&lgr;(T)dependence reveals the existence of a phonon scattering mechanism with a relaxation rate proportional to the square of the frequency. ©1998 American Institute of Physics.

ISSN:1063-777X    

DOI:10.1063/1.593583

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

It is shown that the damping decrement for acoustic waves in a layered conductor with a quasi-two-dimensional electron energy spectrum depends considerably on the orientation of the magnetic field relative to the layers in a wide range of magnetic fields if charge carriers can drift along the sound wave vector. The positions of extrema on the angular dependence of the sound damping decrement contain detailed information on the Fermi surface. ©1998 American Institute of Physics.

ISSN:1063-777X    

DOI:10.1063/1.593584

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Propagation of electromagnetic waves is studied theoretically in layered organic conductors with metal-type conductivity, whose Fermi surface (apart from a slightly corrugated cylinder)a prioricontains two sheets in the form of weakly corrugated planes. It is shown that the presence of such a group of charge carriers significantly affects the magnitude of wave attenuation. ©1998 American Institute of Physics.

ISSN:1063-777X    

DOI:10.1063/1.593585

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The process of matrix isolation of nitrogen atoms in solidN2is studied by the method of condensation from the gaseous phase. In order to vary the flow rates of nitrogen atoms and molecules at the sample surface over a wide range,N2–Hemixtures of various compositions have been passed through the gas discharge zone. It is found that the EPR line width for N atoms inN2increases upon a decrease in the nitrogen flow rate from the discharge zone to a cold substrate. It is shown that this increase is due to an increase in the concentration of atomic nitrogen in the matrix leading to an enhancement of the dipole–dipole interaction between atoms. It is established that a decrease in the intensity of recombination of atoms in the course of diffusion at the sample surface due to a decrease in the surface density of these atoms plays a decisive role in the growth of the concentration of matrix-isolated atoms in the experiments. It is found that for a constant flow rate of atoms from the discharge, their concentration in the matrix increases and attains saturation upon an increase in the discharge intensity. The dependence of concentration on the discharge intensity is attributed to a change in the degree of dissociation of molecular nitrogen in the discharge. ©1998 American Institute of Physics.

ISSN:1063-777X    

DOI:10.1063/1.593586

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Transmission spectrum ofCsDy(MoO4)2single crystals is measured in polarized light in the longwave IR region (10–100 cm−1)at low temperatures 6–40 K. The change in the vibrational spectrum during first-order structural phase transition(Tc∼38 K)is detected experimentally. The vibrational spectrum ofCsDy(MoO4)2is analyzed in the model of “quasi-chipped off” vibrational modes. ©1998 American Institute of Physics.

ISSN:1063-777X    

DOI:10.1063/1.593587

出版商:AIP    

年代:1998

数据来源: AIP