2025/04/22 by V. Sunko, S. Ahsanullah, Sunko, V. +13 · 1 voice
Physics and Astronomy · Materials Science · #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Magnetism in coordination complexes
paper · doi:10.1038/s41467-026-72577-4
openalex created_date 2025/10/11 · openalex publication_date 2026/05/12 · openalex updated_date 2026/07/31
Abstract Magneto-optic Kerr effect (MOKE) is a powerful probe of broken time-reversal symmetry ( T <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>T</mml:mi> </mml:math> ), 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 MnBi 2 Te 4 , an A-type AFM where T <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>T</mml:mi> </mml:math> 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.