Field-induced topological Hall effect in the noncoplanar triangular antiferromagnetic geometry of Mn3Sn

Abstract

Non-collinear triangular antiferromagnets with a coplanar spin arrangement and vanishing net magnetic moment can exhibit a large anomalous Hall effect owing to their non-vanishing momentum space Berry curvature. Here we show the existence of a large field induced topological Hall effect in the non-coplanar triangular antiferromagnetic geometry of Mn3Sn. A detailed magnetic and Hall effect measurements demonstrate the presence of three distinct Hall contributions; a high temperature anomalous Hall effect, a low temperature topological Hall effect and an intermediate temperature region with coexistence of both the effects. The origin of the observed topological Hall effect is attributed to the scalar spin chirality induced real space Berry curvature that appears when the system undergoes from a trivial non-coplanar triangular spin alignment to a topologically protected non-trivial spin texture like skyrmions by application of magnetic field at low temperatures.