Role of non-reciprocity in spin-wave channeling

TL;DR

This study investigates how non-reciprocal acoustic spin waves in synthetic antiferromagnets can be guided and how non-reciprocity influences wave propagation, revealing complex directional behaviors relevant for wave-based technologies.

Contribution

It demonstrates that non-reciprocal spin waves exhibit unexpected propagation signatures even when guided in reciprocal directions, advancing understanding of wave guidance in non-reciprocal magnetic materials.

Findings

Strong non-reciprocal signatures in wave propagation

High wavevector excitation perpendicular to channels

Energy transfer in non-aligned directions

Abstract

The extent to which non-reciprocal waves can be guided in arbitrary directions is an interesting question. We address one aspect of this problem by studying the propagation of acoustic spin waves in a narrow physical conduit made of a synthetic antiferromagnet. Through a combination of Brillouin Light Scattering microscopy and modeling, we demonstrate that even when attempting to guide waves in the reciprocal direction of the material, the system still exhibits strong signatures of non-reciprocity. This includes the excitation of high wavevector waves in the direction perpendicular to the intended channeling, as well as energy transfer in directions that often neither aligns with the physical conduit nor with the symmetry axes of the magnetic properties. These findings have implications for the modeling of propagating wave spectroscopy in non-reciprocal materials and their potential applications.