Spin wave theory of double exchange ferromagnets

We construct the 1/S spin wave expansion for double exchange: ferromagnets at T = 0. It is assumed that the value of Hund's rule coupling, J(H), is sufficiently large, resulting in a fully saturated, ferromagnetic half-metallic ground state. We evaluate corrections to the magnon dispersion law, and we also find that, in contrast to earlier statements in the Literature, magnon-electron scattering does give rise to spin wave damping. We analyze the momentum dependence of these quantities and discuss the experimental implications for colossal magnetoresistance compounds.