In the non-collinear antiferromagnet Mn3Sn, we compare simultaneous measurements of the anomalous Hall effect (AHE) and the magneto-optical Kerr effect (MOKE) through two magnetic phase transitions: the high-temperature paramagnetic/antiferromagnetic phase transition at the N\'eel temperature (TN≈420~K), and a lower-temperature incommensurate magnetic ordering at T1≈270~K. While both the AHE and MOKE are sensitive to the same underlying symmetries of the antiferromagnetic non-collinear spin order, we find that the transition temperatures measured by these two techniques unexpectedly differ by approximately 10~K. Moreover, the applied magnetic field at which the antiferromagnetic order reverses is significantly larger when measured by MOKE than when measured by AHE. These results point to a difference between the bulk and surface magnetic properties of Mn3Sn.
@article{arxiv.1901.07642,
title = {Comparing the anomalous Hall effect and the magneto-optical Kerr effect through antiferromagnetic phase transitions in Mn$_3$Sn},
author = {A. L. Balk and N. H. Sung and S. M. Thomas and P. F. S. Rosa and R. D. McDonald and J. D. Thompson and E. D. Bauer and F. Ronning and S. A. Crooker},
journal= {arXiv preprint arXiv:1901.07642},
year = {2019}
}