Exchange-biasing topological charges by antiferromagnetism.

He, Qing Lin; Yin, Gen; Grutter, Alexander J; Pan, Lei; Che, Xiaoyu; Yu, Guoqiang; Gilbert, Dustin A; Disseler, Steven M et al. · Nat Commun · 2018

basic_science · Level V

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Abstract

Geometric Hall effect is induced by the emergent gauge field experienced by the carriers adiabatically passing through certain real-space topological spin textures, which is a probe to non-trivial spin textures, such as magnetic skyrmions. We report experimental indications of spin-texture topological charges induced in heterostructures of a topological insulator (Bi,Sb)<sub>2</sub>Te<sub>3</sub> coupled to an antiferromagnet MnTe. Through a seeding effect, the pinned spins at the interface leads to a tunable modification of the averaged real-space topological charge. This effect experimentally manifests as a modification of the field-dependent geometric Hall effect when the system is field-cooled along different directions. This heterostructure represents a platform for manipulating magnetic topological transitions using antiferromagnetic order.