Preferential excitation of a single nanomagnet using magnetoelastic coupling

Abstract

We report preferential excitation and detection of the precessional spin dynamics of individual nanomagnets via magnetoelastic (MEL) resonance excitation. Surface acoustic waves (SAWs) are generated via the ultrafast optical excitation of a nonmagnetic grating (Al bars) with lithographically defined acoustic eigenmodes. We show that the precessional spin dynamics in two identical, elliptical nanomagnets with orthogonal orientations can be selectively excited by the SAWs via control of the applied magnetic field. Furthermore, we observe that both the amplitude and damping of the magnetoelastically induced precession depend on the relative orientation of the SAW with respect to the nanomagnets. Using magnetomechanical simulations, we show that the acoustic excitation is most efficient when the spatial distributions of the natural and SAW-driven magnetic resonances overlap. These findings reveal a direct connection between the geometry and MEL excitation efficiency and have implications for the rational design of nanoscale magnetomechanical devices.