Magneto-optical Kerr effect in an A-type antiferromagnet
Journal article, 2026
Magneto-optic Kerr effect (MOKE) is a powerful probe of broken time-reversal symmetry (T), typically used to study ferromagnets. While MOKE has been observed in some antiferromagnets (AFMs) with vanishing magnetization, it is often associated with structures whose symmetry is lower than basic collinear, bipartite order. In contrast, theory predicts a mechanism for MOKE intrinsic to all AFMs of A-type, i.e. layered AFMs in which ferromagnetic layers are antiferromagnetically aligned. Here we report the experimental confirmation of this mechanism in a bulk AFM. We achieve this by measuring the imaginary component of MOKE as a function of photon energy in MnBi2Te4, an A-type AFM where T is preserved in combination with a translation, and comparing the experimental results with model calculations. Our model suggests that observable MOKE should be expected in all collinear A-type AFMs with out-of-plane spin order, thus enabling optical detection of AFM domains and expanding the scope of MOKE to few-layer AFMs.
Author
Veronika Sunko
University of California
Lawrence Berkeley National Laboratory
Institute of Science and Technology Austria
Salman Ahsanullah
University of Kansas
Vivek Jain
University of Kansas
Sophie Frances Liss Weber
Chalmers, Physics, Condensed Matter and Materials Theory
Sivaloganathan Kumaran
University of Cambridge
J. Yan
Oak Ridge National Laboratory
Joseph Orenstein
University of California
Lawrence Berkeley National Laboratory
Dmitry Ovchinnikov
University of Kansas
Nature Communications
2041-1723 (ISSN) 20411723 (eISSN)
Vol. 17 1 7364Subject Categories (SSIF 2025)
Condensed Matter Physics
DOI
10.1038/s41467-026-72577-4
PubMed
42120877
Related datasets
Datasets [dataset]
URI: https://doi.org/10.15479/AT-ISTA-21422