Theory of inelastic light scattering by ferromagnetic polaritons

Using classical equations of motion together with Maxwell's equations, the authors calculate the response of a ferromagnet to an applied RF magnetic field, including the effects of retardation. With the aid of the fluctuation-dissipation theorem the response functions are used to find the correlation functions required for an evaluation of the cross section for inelastic light scattering. The dispersion relation and cross section are discussed in detail at zero temperature, and some discussion is given of the corresponding results at low, but non-zero, temperature.