Control of spin waves by spatially modulated strain

Abstract

We suggest using spatially modulated strain for control of a spin wave propagating inside a bulk magnet. The modulation with the wave vector $q=2k$, by virtue of magnetoelasticity, mixes spin waves with wave vectors near $k$ and $-k$. This leads to lifting the degeneracy of the symmetric and antisymmetric eigenstate combinations of these waves. The resulting picture reminds one of a tunneling particle in a symmetric double-well potential. Here, a moving spin wave being subjected to the $2k$-lattice modulation after some time alters its propagation direction to the opposite one, and so on. The effect can be utilized for the control of the spin-wave propagation that can be useful for spintronic and magnonic applications. The control may include a delay line element, filtering, and waveguide of the spin waves.