Switching of magnetic domains in a noncollinear antiferromagnet at the nanoscale

TL;DR

This study investigates how magnetic domains in noncollinear antiferromagnetic Mn3Sn nanostructures switch under magnetic fields, revealing partial switching and pinning effects related to grain boundaries, with implications for spintronic device control.

Contribution

It demonstrates nanoscale magnetic switching behavior in Mn3Sn thin films and links pinning effects to crystal grain boundaries, advancing understanding of antiferromagnetic domain control.

Findings

Partial magnetic ordering induced by external fields in Mn3Sn nanostructures

Visualization of switching along multiple easy axes

Pinning behavior correlated with grain boundaries

Abstract

Antiferromagnets that display very small stray magnetic field are ideal for spintronic applications. Of particular interest are non-collinear, chiral antiferromagnets of the type Mn3X (X=Sn, Ge), which display a large magnetotransport response that is correlated with their antiferromagnetic ordering. The ability to read out and manipulate this ordering is crucial for their integration into spintronic devices. These materials exhibit a tiny unbalanced magnetic moment such that a large external magnetic field can, in principle, be used to set the material into a single antiferromagnetic domain. However, in thin films of Mn3Sn, we find that such fields induce only a partial magnetic ordering. By detecting two orthogonal in-plane components of the magnetic order vector, we find that the non-switchable fraction has a unidirectional anisotropy. This also enables us to visualize switching along multiple easy axes in Mn3Sn. Studying the switching at the nanoscale allows us to correlate the pining behavior to crystal grain boundaries in the Mn3Sn nanowire structures.