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MA: Fachverband Magnetismus

MA 11: Functional Antiferromagnetism

MA 11.7: Talk

Monday, March 18, 2024, 16:30–16:45, EB 202

Revealing the higher-order spin nature of the Hall effect in non-collinear antiferromagnet Mn3Ni0.35Cu0.65N — •Adithya Rajan¹, Tom G. Saunderson¹, Fabian R. Lux¹, Dongwook Go², Hasan M. Abdullah³, Arnab Bose¹, Udo Schingenschögl³, Aurélien Manchon⁴, Yuriy Mokrousov^1,2, and Mathias Kläui¹ — ¹Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany — ²Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich, 52424 Jülich, Germany — ³King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia — ⁴CINaM, Aix-Marseille Université, CNRS, Marseille, France

We reveal [1] the complex origin of the anomalous Hall effect arising in noncollinear antiferromagnets by performing Hall measurements with fields applied in selected crystalline directions. Our coplanar magnetic field geometry goes beyond the conventional perpendicular field geometry used for ferromagnets and allows us to suppress any magnetic dipole contribution. We map the in-plane anomalous Hall contribution and demonstrate a 120 ° symmetry governed by the octupole moment at high fields. At low fields we subsequently discover a surprising topological Hall-like signature, and, from a combination of theoretical techniques, we show that the spins can be recast into dipole, emergent octupole and noncoplanar effective magnetic moments. These co-existing orders enable magnetization dynamics unachievable in either ferromagnetic or conventional collinear antiferromagnetic materials.

[1] A. Rajan, et al., arXiv:2304:10747 (2023)

Keywords: noncollinear; antiferromagnets; Anomalous Hall effect; Topological Hall effect; Scalar spin chirality