We study the magneto-optical Kerr effect (MOKE) in SrRuO3 thin films, uncovering wide regimes of wavelength, temperature, and magnetic field where the Kerr rotation is not simply proportional to the magnetization but instead displays two-component behavior. One component of the MOKE signal tracks the average magnetization, while the second "anomalous" component bears a resemblance to anomalies in the Hall resistivity which have been previously reported in skyrmion materials. We present a theory showing that the MOKE anomalies arise from the non-monotonic relation between the Kerr angle and the magnetization, when we average over magnetic domains which proliferate near the coercive field. Our results suggest that inhomogeneous domain formation, rather than skyrmions, may provide a common origin for the observed MOKE and Hall resistivity anomalies.
@article{arxiv.1908.08974,
title = {Anomalous Kerr Effect in SrRuO$_3$ Thin Films},
author = {F. Michael Bartram and Sopheak Sorn and Zhuolu Li and Kyle Hwangbo and Shengchun Shen and Felix Frontini and Liqun He and Pu Yu and Arun Paramekanti and Luyi Yang},
journal= {arXiv preprint arXiv:1908.08974},
year = {2020}
}