Spin‐Wave Relaxation in Ferromagnetic Alloys

The relaxation width of ferromagnetic and spin‐wave resonance lines in disordered alloys is investigated. Long‐wave spin waves are obtained in this system using simplest approximations (based on averaging over a physically small volume). The relaxation of these spin waves is due to the absorption of magnons by conduction electrons. The presence of disorder in the system leads to the non‐conservation of the total quasi‐momentum in these processes, thus making them effective, in contrast to ordered metals and alloys. The linewidth obtained, ΔB, is proportional to the resonance frequency and residual resistivity, and inversely proportional to the saturation magnetization. Both the linewidth and its dependence on the parameters are in good agreement with experiment.