Physics

Magnetization dynamics

Magnetization

Ferromagnetic resonance

Ferromagnetism

Millimeter

Magnetic field

Optics

Coupling (piping)

Angular momentum

Magnon

Metallurgy

Materials science

Phonon

Condensed matter physics

Quantum mechanics

Physical review. B./Physical review. B

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.

Coherent long-range transfer of angular momentum between magnon Kittel modes by phonons