Spin Exchange Effects in Ferromagnetic Resonance

A discussion of theoretical and experimental work concerned with spin exchange effects in ferromagnetic resonance is given. Qualitative and quantitative results of the author's exchange theory are summarized together with work of Ament and Rado in the same field. An approximate solution of the exchange problem due to the latter authors is used to analyze the recent ferromagnetic resonance results of Hoskins and Wiener on permalloys. Such analysis indicates that some of the observed effects may have arisen from exchange but that it cannot explain the observed experimental $g$ shifts from the free-spin value.