Geometric magnonics with chiral magnetic domain walls

TL;DR

This paper demonstrates that spin wave propagation across chiral magnetic domain walls follows geometric trajectories akin to optics, revealing polarization-dependent effects and new scattering phenomena in magnetic textures.

Contribution

It introduces a geometric optics framework for understanding spin wave behavior in chiral magnetic textures, highlighting novel polarization-dependent effects in antiferromagnetic domain walls.

Findings

Spin wave trajectories follow simple geometric paths across domain walls.

Lateral shift, refraction, and total reflection are observed in ferromagnetic films.

Spin wave birefringence emerges inside antiferromagnetic domain walls.

Abstract

Spin wave, the collective excitation of magnetic order, is one of the fundamental angular momentum carriers in magnetic systems. Understanding the spin wave propagation in magnetic textures lies in the heart of developing pure magnetic information processing schemes. Here we show that the spin wave propagation across a chiral domain wall follows simple geometric trajectories, similar to the geometric optics. And the geometric behaviors are qualitatively different in normally magnetized film and tangentially magnetized film. We identify the lateral shift, refraction, and total reflection of spin wave across a ferromagnetic domain wall. Moreover, these geometric scattering phenomena become polarization-dependent in antiferromagnets, indicating the emergence of spin wave birefringence inside antiferromagnetic domain wall.