Magnetic domain wall motion driven by an acoustic wave
Dynamic interaction of acoustic and magnetic systems is of strong current interest, triggered by the promises of almost lossless new concepts of magnet-based information technology. In such concepts, a significant role is often given to domain walls (DW). Therefore, here we investigate how launching an acoustic shear wave, we can control the DW motion. Surprisingly, at sufficiently large amplitudes of the shear displacement, the speed of the forced DW motion can reach sizeable fraction of the speed of sound. This was shown to happen due to certain resonance conditions depending on the wave frequency, its angle of incidence, and shear displacement amplitudes, leading to a total reflection of the wave and maximizing the impact. Most interesting, strong nonlinearity appears in the interaction of the elastic and magnetic subsystems, expressed by the negative slope of the resonant reflection peak and the s-shaped dependence of the domain wall velocity on the shear displacement amplitude, typical for nonlinear systems.