A route towards stable homochiral topological textures in A-type antiferromagnets

TL;DR

This paper explores how to stabilize and control topological magnetic textures in A-type antiferromagnets, especially α-Fe₂O₃, using interfacial Dzyaloshinskii-Moriya interaction, advancing AFM spintronics.

Contribution

It introduces a comprehensive model for stabilizing and tuning homochiral topological textures in A-type antiferromagnets, including the discovery of AFM skyrmions.

Findings

iDMI stabilizes homochiral AFM textures

Anisotropy and exchange tuning control core size

α-Fe₂O₃ is a promising material platform

Abstract

Topologically protected whirling magnetic textures could emerge as data carriers in next-generation post-Moore computing. Such textures are abundantly observed in ferromagnets (FMs); however, their antiferromagnetic (AFM) counterparts are expected to be even more relevant for device applications, as they promise ultra-fast, deflection-free dynamics whilst being robust against external fields. Unfortunately, they have remained elusive, hence identifying materials hosting such textures is key to developing this technology. Here, we present comprehensive micromagnetic and analytical models investigating topological textures in the broad material class of A-type antiferromagnets, specifically focusing on the prototypical case of $\alpha \text{-Fe}_2 \text{O}_3$,an emerging candidate for AFM spintronics. By exploiting a symmetry breaking interfacial Dzyaloshinskii-Moriya interaction (iDMI), it is possible to stabilize a wide topological family, including AFM (anti)merons and bimerons and the hitherto undiscovered AFM skyrmions. Whilst iDMI enforces homochirality and improves the stability of these textures, the widely tunable anisotropy and exchange interactions enable unprecedented control of their core dimensions. We then present a unifying framework to model the scaling of texture sizes based on a simple dimensional analysis. As the parameters required to host and tune homochiral AFM textures may be obtained by rational materials design of $\alpha \text{-Fe}_2 \text{O}_3$, it could emerge as a promising platform to initiate AFM topological spintronics.