Abstract
The Landau-Lifshitz theory of ferromagnetic spin waves is generalized to amorphous ferromagnetic materials. It is shown that this theory predicts the existence of both extended and localized spin-wave states. The localized states are due to the randomness of the ferromagnet. It is postulated that the localized spin waves can be resonantly excited by means of a time-varying electromagnetic field. The anomalously large widths of the resonance lines observed in recent spin wave resonance experiments performed on amorphous thin nickel films can be explained in terms of the localized spin-wave states.
Supported in part by the National Science Foundation
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References
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This resonance condition is also reasonable for the localized spin waves. It will turn out that K−1 is on the order of 2500 Å, hence the magnitude of the localized spin waves will remain almost constant across the film.
R.G. Henderson and A.M. de Graaf, unpublished.
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© 1973 Plenum Press
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Henderson, R.G., de Graaf, A.M. (1973). Semi-Classical Theory of Spin Wave Excitations in Amorphous Ferromagnets. In: Hooper, H.O., de Graaf, A.M. (eds) Amorphous Magnetism. Springer, Boston, MA. https://doi.org/10.1007/978-1-4613-4568-8_36
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DOI: https://doi.org/10.1007/978-1-4613-4568-8_36
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