We perform hysteresis-loop measurement and domain imaging for -oriented D019-Mn3+xSn1-x () thin films using the magneto-optical Kerr effect (MOKE) and compare it with the anomalous Hall effect (AHE) measurement. We obtain a large Kerr rotation angle of 10 mdeg, comparable with bulk single-crystal Mn3Sn. The composition x dependence of AHE and MOKE shows a similar trend, suggesting the same origin, i.e., the non-vanishing Berry curvature in the momentum space. Magnetic domain observation at the saturated state shows that x dependence of AHE and MOKE is explained by the amount of the reversible area that crucially depends on the crystalline structure of the film. Furthermore, in-depth observation of the reversal process reveals that the reversal starts with nucleation of sub-micrometer-scale domains dispersed in the film, followed by domain expansion, where the domain wall preferentially propagates along the direction. Our study provides a basic understanding of the spatial evolution of the reversal of the chiral-spin structure in non-collinear antiferromagnetic thin films.
Observation of domain structure in non-collinear antiferromagnetic Mn3Sn thin films by magneto-optical Kerr effect
Tomohiro Uchimura, Ju-Young Yoon, Yuma Sato, Yutaro Takeuchi, Shun Kanai, Ryota Takechi, Keisuke Kishi, Yuta Yamane, Samik DuttaGupta, Jun'ichi Ieda, Hideo Ohno, Shunsuke Fukami; Observation of domain structure in non-collinear antiferromagnetic Mn3Sn thin films by magneto-optical Kerr effect. Appl. Phys. Lett. 25 April 2022; 120 (17): 172405. https://doi.org/10.1063/5.0089355
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