Berlin 2024 – scientific programme
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MA: Fachverband Magnetismus
MA 11: Functional Antiferromagnetism
MA 11.12: Talk
Monday, March 18, 2024, 18:00–18:15, EB 202
Surface-symmetry-driven phenomena in magnetoelectric Cr2O3 — •Oleksandr V. Pylypovskyi1,2, Sophie F. Weber3, Pavlo Makushko1, Igor Veremchuk1, Nicola A. Spaldin3, and Denys Makarov1 — 1Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, 01328 Dresden, Germany — 2Kyiv Academic University, 03142 Kyiv, Ukraine — 3Materials Theory, ETH Zürich, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland
Antiferromagnetic (AFM) Cr2O3 is a unique collinear magnetoelectric material at room temperature. The bulk properties stemming from its magnetic symmetry render chromia of high interest for fundamentals and applications [1]. Features of the chromia surface remain much less explored. Here, we consider nominally compensated surfaces (m and a planes) of Cr2O3 [2]. We show that they provide a sizeable Dzyaloshinskii–Moriya interaction (DMI) determined by the surface magnetic symmetry point group and quantify it to be about 1 mJ/m2 by means of ab initio and micromagnetic approaches. The DMI leads to the development of nonzero surface magnetization M→ whose sign is uniquely determined by the AFM state. The m and a planes of Cr2O3 behave as the canted ferrimagnet and canted 4-sublattice antiferromagnet, respectively. The coupling of M→ to the direction of the Néel vector is shown by magnetotransport measurements.
[1] P. Makushko et al., Nat. Comm. 13, 6745 (2022). [2] O.V. Pylypovskyi, S. F. Weber et al., ArXiv:2310.13438 (2023).