A micromagnetic study of surface-acoustic-wave-driven excitation of spin waves in an iron-based conduit

Abstract

We propose a magnonic device based on resonant magnetoelastic coupling and surface acoustic waves as an alternative way to excite spin waves. Using micromagnetic simulations, we study the generation and propagation of spin waves in an FeN waveguide from the excitation of an inserted Fe pad using surface acoustic waves. First, we derive the approximate but reliable expression for the effective magnetoelastic field taking into account the magnetorotative contribution and the geometry of the system. Second, we show that a propagating spin wave generated from the Fe pad is obtained with an attenuation length of around 2 μm. By studying the behavior of the spin wave in the conduit as a function of the external field and the surface acoustic wave frequency, we deduce the optimal working conditions for the system. Interestingly, an asymmetric propagation of spin waves in the conduit is clearly anticipated by simulations.