Magnetic excitations in ferromagnetic semiconductors,and their study by light scattering

The magnetic excitation spectrum of degenerate ferromagnetic semiconductors, described by the s-f interaction model, is investigated by calculating various Green functions which provide the dynamic response of the system. In addition to the usual acoustic spin-wave mode, there are also an optical spin-wave branch and the Stoner-like continuum of excitations. Some estimates are made for the first order light scattering from ferrmagnetic semiconductors at low temperatures T?T_c.