Excitation of gigahertz magnetoelastic waves in dysprosium films: Frequency dependence

Abstract

Application of a tunable spin-phonon spectrometer to the study of microwave phonon excitations over more than an octave in frequency in polycrystalline films of dysprosium is shown to provide direct information about the coupled magnetoelastic modes. In particular, experiments demonstrate that a rf magnetic field couples to the "phononlike" branch of the magnetoelastic dispersion curves, and the attenuation of the rf field in the films leads to $q\ne 0$ momentum conservation. The observed phonon signal intensity at the rf frequency ${\nu }_0$ is shown to be in excellent agreement with intensities computed from the coupled-mode dispersion relations.