Spin waves in thin films and magnonic crystals with Dzyaloshinskii-Moriya interactions

TL;DR

This paper reviews how Dzyaloshinskii-Moriya interactions influence spin wave behavior in thin films and chiral magnonic crystals, highlighting non-reciprocal spectra and novel phenomena like flat bands and gaps.

Contribution

It introduces the concept of chiral magnonic crystals with periodic Dzyaloshinskii-Moriya interactions and discusses their unique effects on spin-wave properties.

Findings

Dzyaloshinskii-Moriya interaction causes non-reciprocal spin-wave spectra.

Periodic Dzyaloshinskii-Moriya interactions lead to flat bands and indirect gaps.

Chiral magnonic crystals exhibit unusual spin-wave evolution.

Abstract

The influence of the Dzyaloshinskii-Moriya interaction in ultra-thin ferromagnetic films and chiral magnonic crystals on the behavior of spin waves is reviewed. During the last decade, it has been shown, both theoretically and experimentally, that this anisotropic exchange interaction produces non-reciprocal features on the spin-wave spectrum of a magnetic system, a phenomenon that occurs both for bulk and interfacial Dzyaloshinskii-Moriya coupling. More recently, the concept of a chiral magnonic crystal has been introduced, where the interfacial Dzyaloshinskii-Moriya interaction is periodic. The effect of this periodicity include additional features such as flat bands, indirect gaps, and an unusual spin-wave evolution.