Observations of the anomalous Hall effect in RuO2 and MnTe have demonstrated unconventional time-reversal symmetry breaking in the electronic structure of a recently identified new class of compensated collinear magnets, dubbed altermagnets. While in MnTe the unconventional anomalous Hall signal accompanied by a vanishing magnetization is observable at remanence, the anomalous Hall effect in RuO2 is excluded by symmetry for the N\'eel vector pointing along the zero-field [001] easy-axis. Guided by a symmetry analysis and ab initio calculations, a field-induced reorientation of the N\'eel vector from the easy-axis towards the [110] hard-axis was used to demonstrate the anomalous Hall signal in this altermagnet. We confirm the existence of an anomalous Hall effect in our RuO2 thin-film samples whose set of magnetic and magneto-transport characteristics is consistent with the earlier report. By performing our measurements at extreme magnetic fields up to 68 T, we reach saturation of the anomalous Hall signal at a field Hc≃ 55 T that was inaccessible in earlier studies, but is consistent with the expected N\'eel-vector reorientation field.
@article{arxiv.2309.00568,
title = {Saturation of the anomalous Hall effect at high magnetic fields in altermagnetic RuO2},
author = {Teresa Tschirner and Philipp Keßler and Ruben Dario Gonzalez Betancourt and Tommy Kotte and Dominik Kriegner and Bernd Buechner and Joseph Dufouleur and Martin Kamp and Vedran Jovic and Libor Smejkal and Jairo Sinova and Ralph Claessen and Tomas Jungwirth and Simon Moser and Helena Reichlova and Louis Veyrat},
journal= {arXiv preprint arXiv:2309.00568},
year = {2024}
}