INFLUENCE OF TRANSLATIONAL SYMMETRY OF FERROMAGNETIC SUPERLATTICES IN THE STUDY OF ELEMENTARY EXCITATIONS

Abstract

Elementary excitations in ferromagnetic superlattices are analyzed theoretically using the transfer matrix method. The method is extended to enable the study of the cases when the boundaries are not consisting of a single plane, but of a complete cell. In this way, semi-infinite superlattice, the interface between two superlattices and the film built of a superlattice are treated. However, it is shown that the choice of the transfer matrix strongly depends on the translational symmetry of the remaining part of the system. Energies of localized excitations are derived and compared both with bulk and the results of standard transfer matrix treatment proposed by Barnas. Also, a special Ansatz for spin amplitudes is proposed leading to identical results with the transfer matrix method and introducing large simplifications.