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MA: Fachverband Magnetismus

MA 49: Focus Session: Higher-Order Magnetic Interactions – Implications in 2D and 3D Magnetism II

MA 49.2: Vortrag

Donnerstag, 19. März 2020, 15:30–15:45, HSZ 04

Origin of the short-period magnetic structure of MnGe from a first-principles high-temperature free energy — •Eduardo Mendive Tapia^1,2, Manuel dos Santos Dias¹, Stefan Blügel¹, and Samir Lounis¹ — ¹Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany — ²Department of Computational Materials Design, Max-Planck Institut für Eisenforschung, 40237 Düsseldorf, Germany

The helimagnetism of B20-type compounds such as MnSi and FeGe is usually understood as a competition between the ferromagnetic exchange interaction and the chiral Dzyaloshinskii-Moriya interaction. The magnetism of MnGe defies this interpretation owing to the short-period of its 3q magnetic structure and distinct B-T magnetic phase diagram [1]. Using a Disordered Local Moment theory implemented in the Korringa-Kohn-Rostoker method [2,3], we construct a first-principles high-temperature free energy for MnGe, which explains the short-period from competing long-range interactions. Our calculations also reproduce experimental volume-dependence of both the period and the Néel transition temperature. The first-principles magnetic phase diagram obtained points to the importance of higher-order magnetic exchange interactions to explain the observed 3q and 4q magnetic structures.—Work funded by the DAAD and EU Horizon 2020 via ERC-consolidator Grant No. 681405–DYNASORE.

[1] Fujishiro et al., Nat. Commun. 10, 1059 (2019)

[2] Gyorffy et al., J. of Phys. F: Metal Phys. 15, 1337 (1985)

[3] Jülich KKR codes (https://jukkr.fz-juelich.de)