Optical probing of Rayleigh wave driven magneto-acoustic resonance

The resonant interaction of electrically excited travelling surface acoustic waves and magnetization has been hitherto probed through the acoustic component. In this work it is investigated using time-resolved magneto-optical detection of magnetization dynamics. To that end, we develop an experimental scheme where laser pulses are used both to generate the acoustic wave frequency and to probe magnetization dynamics thus ensuring perfect phase locking. The light polarization dependence of the signal enables to disentangle elasto-optic and magneto-optic contributions and to obtain the in-plane and out-of-plane dynamic magnetization components. Magnetization precession is proved to be driven solely by the acoustic wave. Its amplitude is shown to resonate at the same field at which we detect piezo-electrically the resonant attenuation of the acoustic wave, clearly evidencing the magneto-acoustic resonance with high sensitivity.