Sukhorukova O. Spin - wave acoustics of the magnetic phononic crystals

The theoretical study of distribution and localization of elastic waves conditions in the one-dimensional (1D) magnetic phononic crystals (MPhC) of type "magnetic - ideal superconductor" is the purpose of dissertation. The models of easy-axis one-sublattice ferromagnet, two-sublattice antiferromagnet and ferrimagnet were considered as magnetic mediums. In the present work the generalization of effective medium method is performed first for the purpose of correct describing the influence of dynamic magnetoelastic interaction on the acoustic dynamics of 1D acoustically gyrotropic and acoustically nongyrotropic MPhC in long-wave approximation. On the ground of this method the conditions, allowing possibility of origination of the new anomalies in the reflection and transmission of the bulk shear wave, are determined. The bulk shear wave incident on the external surface of the thin-layered 1D MPhC is considered. The localization conditions for the surface shear acoustic waves on the interface "1D MPhC - nonmagnetic media" are investigated for the first time. For the purpose of experimental investigation of this type of the surface excitations in magnetic superlattices, the acoustic analogues of the Otto's and Krechmann's schemes, widely used in optics, were suggested and theoretically studied. A new mechanism for enhancement of evanescent shear waves is found through the limited thin-layered 1D MPhC.