Volume 35, Issue 11, November 2009
Index of content:
- LOW-TEMPERATURE MAGNETISM
35(2009); http://dx.doi.org/10.1063/1.3266915View Description Hide Description
The excitation of electromagnons in the ferroelectromagnetic phase of by an electromagnetic wave is considered for different polarizations of the wave. In the case when the electric field of the wave is oriented perpendicular to the spontaneous polarization of the crystal, the results of calculations show that the frequency of the resonance absorption is independent of temperature, in agreement with experiment. When the electric field is directed along the spontaneous polarization it is predicted that the temperature and frequency dependence of the dielectric loss will have anomalies near the temperature of the ferroelectric transition.
35(2009); http://dx.doi.org/10.1063/1.3266916View Description Hide Description
The temperature dependences of the magnetic susceptibility and its anisotropy have been measured for hexagonal single crystals of transition-metal diborides in the temperature interval . It is found that the anisotropy is weakly temperature-dependent, a nonmonotonic function of the filling of the hybridized conduction band, and largest for group-IV transition metals. First-principles calculations of the electronic structure of diborides and the values of the paramagnetic contributions (spin and Van Vleck) to their susceptibility show that the behavior of the magnetic anisotropy is due to the competition between Van Vleck paramagnetism and orbital diamagnetism of the conduction electrons.
35(2009); http://dx.doi.org/10.1063/1.3266917View Description Hide Description
The results of theoretical calculations and experimental data for the effective magnetic anisotropy (obtained from ferromagnetic resonance measurements) of superlattices with a coherent interaction of the Co and Cu layers prepared by magnetron sputtering are presented. The experimental values of are an oscillatory function of the thickness interlayers. The computed and experimentally measured dependences are qualitatively similar; stable growth of the parameter with increasing thickness of the nonmagnetic layers is observed (against the background of oscillations of the experimental curve), which is a direct consequence of the growth of axial distortions of the initial cubic structure of cobalt under the conditions of pseudomorphism. The reasons for the appearance of oscillations of are discussed; the main one is the oscillatory behavior of the roughness of the interfaces of the layers with increasing , resulting in synchronous oscillations of , resistivity, magnetoresistance, and the ferromagnetic resonance linewidth.