Theory of surface spin waves in ferromagnetic semiconductors

Abstract

A Green's-function formalism combined with the transfer-matrix method is used to calculate the surface spin wave modes in semi-infinite ferromagnetic semiconductors ͑FMS's͒ with a ͑001͒ surface and the surface magnetization in the ferromagnetic phase, TрT c . The theoretical results were applied to narrow-band as well as to wide-band FMS's. ͓S0163-1829͑98͒02811-2͔

Magnetic Properties of Thin Ferromagnetic Semiconducting Films

“…Gopalan and Cottam [23] have used the s±d interaction model to study the bulk and surface magnetic excitations of a semi-infinite FMS. Results are deduced for both narrow-band and wide-band FMS, but only for low temperatures, T ( T C , where the magnetization hS z i S. Wesselinowa et al [24] have calculated the surface excitations and surface magnetization in FMSs using a Green's function technique combined with the transfer-matrix method in both cases, narrow-band as well as wide-band FMSs for all temperatures below T C . The aim of the present paper is to study the magnetization and the Curie temperature in dependence on the thickness of a thin FMS-ing film containing conduction-band electrons and localized spins, using a Green's function theory developed for ferromagnetic thin films by Haubenreisser et al [25].…”