Regensburg 2019 – scientific programme

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MA: Fachverband Magnetismus

MA 3: Focus Session: Novel 3D magnetic spin textures

MA 3.9: Talk

Monday, April 1, 2019, 13:00–13:15, H38

Prediction of a novel chiral magnetic interaction originating from the coupling of spin and topological orbital moment in B20 compounds — •S. Grytsiuk, M. Hoffmann, J.-P. Hanke, G. Bihlmayer, Y. Mokrousov, and S. Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

It is believed that the complex magnetic structure of B20 materials, such as FeGe and MnGe, can be explained exclusively in terms of the Heisenberg exchange and antisymmetric Dzyaloshinskii-Moriya (DM) interaction. We demonstrate that this assumption is wrong. We discovered that the spin-spin interactions in MnGe are strongly influenced by the Berry phase effect of carriers hopping in a nontrivial spin background. We show that without SOI the non-coplanar magnetic structure in B20 materials gives rise to a topological orbital moment [1-2]. Moreover, we reveal that in case of MnGe the spin-orbit coupling between the local spins and topological orbital moment dominates over DMI in favoring a magnetic state of certain chirality even without external magnetic field. Together with the biquadratic coupling, that we found important in B20 compounds, we speculate that the corresponding novel chiral magnetic interaction can be a key element in resolving the puzzle of the complex 3D magnetic state of MnGe, and suggest that it can present a platform for realizing new classes of chiral magnetic materials and textures.

[1] M. Hoffmann, at. el., Phys. Rev. B 92, 020401(R) (2015).

[2] J.-P. Hanke, at. el., Sci. Rep. 7, 41078 (2017)