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

Noncollinear triangular antiferromagnets with a coplanar spin arrangement and vanishing net magnetic moment can exhibit a large anomalous Hall effect owing to their nonvanishing momentum space Berry curvature. Here we show the existence of a large field-induced topological Hall effect in the noncoplanar 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 goes from a trivial noncoplanar triangular spin alignment to a topologically protected nontrivial spin texture like skyrmions by application of magnetic field at low temperatures.