Acoustic wave surfing: spin waves and spin pumping driven by elastic wave

Abstract

In magnon spintronics it is fundamental that magnons can propagate over large distances to allow spin flux or information to be processed. Through micromagnetic simulations we investigate the spin-wave propagation driven by acoustic excitation in narrow Ni stripes, varying the level of coupling between spin and acoustic waves. We consider different cases depending on the extension of the acoustic wave propagation, which is generated on the left end of the stripe. When acoustic waves are confined at the origin, the spin waves are free to propagate but vanish after the decay length, which is dependent on the dissipation. On the other hand, when the acoustic waves are present in the whole stripe, spin and acoustic waves propagate together with the spin wave maintaining a constant amplitude. Images of the spin-wave propagation modes and the dispersion relations are discussed for different acoustic wave attenuation lengths. Motivated by recent experiments, we consider a Pt line over and crossing the Ni stripe and calculate the spin and charge current maps at the Ni/Pt interface and the Pt line, respectively, and the AC and DC components of the inverse spin Hall effect voltage.