Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session E05: Anomalous Transverse Transport in Mn3X Non-collinear Antiferromagnets
8:00 AM–11:00 AM,
Tuesday, March 6, 2018
LACC Room: 152
Sponsoring Units: DCMP DCOMP GMAG
Chair: Claudia Felser, Max Planck Inst
Abstract: E05.00002 : Magnetic anti-skyrmions and triangular antiferromagnetism in Mn3X and Mn2XY compounds*
8:36 AM–9:12 AM
It is well established that the anomalous Hall effect displayed by a ferromagnet scales with its magnetization. Therefore, an antiferromagnet that has no net magnetization should exhibit no anomalous Hall effect. We show that, rather, the non-collinear triangular antiferromagnet hexagonal Mn3Ge exhibits a large anomalous Hall effect comparable to that of ferromagnetic metals1. Our theoretical calculations demonstrate that the Hall effect in Mn3Ge originates from a nonvanishing Berry curvature that arises from the chiral spin structure, and that also results in a large spin Hall effect comparable to that of platinum. In the chiral triangular antiferromagnet cubic Mn3Ir, we observe a large spin Hall effect but no evidence for any anomalous Hall effect2. We speculate that this is because the sign of the spin Hall effect is independent of the chirality of the triangular antiferromagnet structure but that the sign of the anomalous Hall effect changes sign with the chirality of the antiferromagnetic structure. Finally, we discuss the discovery of anti-skyrmions in several tetragonal inverse Heusler compounds using Lorentz transmission electron microscopy3 and variable temperature magnetic force microscopy. We discuss the topological Hall effect that we observe in these systems.
1 Nayak, A. K. et al. Large anomalous Hall effect driven by non-vanishing Berry curvature in non-collinear antiferromagnet Mn3Ge Sci. Adv. 2, e1501870, (2016).
2 Zhang, W. et al. Giant facet-dependent spin-orbit torque and spin Hall conductivity in the triangular antiferromagnet IrMn3. Sci. Adv. 2, e1600759, (2016).
3 Nayak, A. K. et al. Magnetic antiskyrmions above room temperature in tetragonal Heusler materials. Nature 548, 561-566, (2017).
*This work was financially supported by the ERC Advanced Grant No. 670166 “SORBET”
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