Interaction of Phonons and Spin Waves

Abstract

Some difficulties in the interpretation of phonon-spin-wave interactions in magnetic films are considered. Experiments by various workers show that there is apparently a large difference in the wavelengths of the interacting phonon and spin waves. Furthermore, phonon excitation of the higher order spin waves is much stronger than expected; in some cases, the higher order spin waves are excited more strongly than are the lower order spin waves. It is shown that no difficulty exists when the spin-wave modes are Hermite functions, since then appreciable Fourier components of the spin-wave modes corresponding to the phonon wavelength exist. The strong dependence of the interaction on film thickenss is explained and the apparently erratic spin-wave-mode intensities appear reasonable on this basis.