No abstract

Using one of the methods of quantum nonequilibrium statistical physics we have investigated the spin transport transverse to the normal metal/ferromagnetic insulator interface in hybrid nanostructures. An approximation of the effective parameters, when each of the interacting subsystems (electron spin, magnon, and phonon) is characterized by its own effective temperature have been considered. The generalized Bloch equations which describe the spin-wave current propagation in the dielectric have been derived. Finally, two sides of the spin transport "coin" have been revealed: the diffusive nature of the magnon motion and magnon relaxation processes, responsible for the spin pumping and the spin-torque effect.

We demonstrate, both experimentally and theoretically, subwavelength waveguiding and imaging through a one-dimensional (1D) array of 3D metallic H-fractals. The waveguide formed by the fractal array is subwavelength in all cross-sectional dimensions, thereby allowing compact designs for guided propagation of long-wavelength EM waves. The underlying physics is governed by the fractal metallic wire structure that allows subwavelength resonances. The measured results indicate that such waveguides can provide low-loss propagation of EM waves with a decay length in the range 10-40 m, achieved through coupling of resonant dipoles/multipoles between neighboring H-fractals along the wave propagation direction. By treating the waveguide as a 1D photonic crystal, the calculated bandstructure shows that in the neighborhood of peak transmission frequencies the dispersion relations are relatively flat as a function of the wave vector, implying low group velocities. This is experimentally verified.Owing to the increased spatial information carried at such transmission frequencies, imaging becomes possible and this was observed by placing an obstacle at the inlet and scanning the local field intensity at the other end of the waveguide.

The results of measurements of the longitudinal Nernst-Ettingshausen effect on Hg,-,Fe,Se samples with different iron content (0 < x < 0.02) at temperatures T between 10 and 60 U are presented. It is shown that the detected non-monotonic temperature dependence of the Nernst-Ettingshausen effect at low temperatures is caused by competition between the phonon drag effect and scattering of electrons by the correlated system of charged Fe3+ iron impurities. Phonon-phonon scattering (the Herring mechanism) and the scattering of phonons nn point defects (the Rayleigh mechanism) are taken into account.

The experimental observations of novel behavior of the kinetic properties of a two-dimensional electron gas in the presence of microwave radiation are reviewed, and the various theoretical models that have been proposed for explaining them are described.