Coherent long-range transfer of angular momentum between magnon Kittel modes by phonons
Kyongmo An, Artem Litvinenko, Ryuhei Kohno, Aufa A. Fuad, V. V. Naletov, L. Vila, U. Ebels, G. de Loubens, H. Hurdequint, Nathan Beaulieu, J. Ben Youssef, N. Vukadinovic, G. Bauer, A. N. Slavin, V. S. Tiberkevich, O. Klein
Abstract
From a ferromagnetic resonance experiment on a YIG|GGG|YIG crystal, phonons are shown to be able to provide coherent long-range coupling between two magnets, which act as ``microphones'' and ``speakers'' for acoustic waves to induce feedback interference over millimeter distances. In this ``phononic spin valve'' under perpendicular magnetization, the phonons, which are circularly polarized, carry efficiently angular momentum current through a nonmagnetic dielectric. The high acoustic quality of phonon transport in garnets and the strong coupling to the magnetic order may also be useful for quantum communication.