Switching of magnetic domains in a noncollinear antiferromagnet at the nanoscale

Antiferromagnets that display very small stray magnetic fields are ideal for spintronic applications. Of particular interest are noncollinear, chiral antiferromagnets of the type Mn 3 X (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 Mn 3 Sn , we find that such fields induce only a partial magnetic ordering. By detecting two orthogonal in-plane components of the magnetic order vector, we can demonstrate switching along multiple easy axes in Mn 3 Sn and find that the nonswitchable fraction has a unidirectional anisotropy. Studying the switching at the nanoscale allows us to correlate the pinning behavior to crystal grain boundaries in the Mn 3 Sn nanowire structures.