Non-Hermitian coherent coupling of nanomagnets by exchange spin waves

TL;DR

This paper demonstrates non-Hermitian coherent coupling of distant nanomagnets via spin waves, enabling unidirectional phase locking, which could advance neuromorphic computing technologies.

Contribution

It introduces a novel non-Hermitian magnonic system where nanomagnets are coupled through fast spin waves, with controllable phase shifts, expanding the understanding of dissipation-enabled magnonics.

Findings

Magnons in nanomagnets are unidirectionally phase-locked.

Spin waves with sub-50 nm wavelengths facilitate coupling.

Phase shifts are controlled by magnon spin torque and propagation.

Abstract

Non-Hermitian physics has recently attracted much attention in optics and photonics. Less explored is non-Hermitian magnonics that provides opportunities to take advantage of the inevitable dissipation of magnons or spin waves in magnetic systems. Here we demonstrate non-Hermitian coherent coupling of two distant nanomagnets by fast spin waves with sub-50 nm wavelengths. Magnons in two nanomagnets are unidirectionally phase-locked with phase shifts controlled by magnon spin torque and spin-wave propagation. Our results are attractive for analog neuromorphic computing that requires unidirectional information transmission.