Spin waves in ferromagnets

In this review a qualitative description is given of the various types of exchange interactions which might be present in metals and insulators and which might lead to co-operative interactions - particularly ferromagnetism. The theory of spin waves is then described and this is extended to include non-linear and temperature effects both in the localized and in the itinerant electron models. The experimental observation of spin-wave phenomena is discussed with particular reference to measurements of the specific heat, the magnetization, inelastic neutron scattering and spin-wave resonance. A short description of spin-wave relaxation mechanisms and of parallel pumping is also given.