Saturation of the anomalous Hall effect at high magnetic fields in altermagnetic RuO2

• Published in: arXiv.org
• Main Authors: Tschirner, Teresa, Keßler, Philipp, Gonzalez Betancourt, Ruben Dario, Kotte, Tommy, Kriegner, Dominik, Buechner, Bernd, Dufouleur, Joseph, Kamp, Martin, Jovic, Vedran, Smejkal, Libor, Sinova, Jairo, Claessen, Ralph, Jungwirth, Tomas, Moser, Simon, Reichlova, Helena, Veyrat, Louis
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 01.09.2023
• Subjects: Broken symmetry; Electromagnetism; Electronic structure; Hall effect; Magnetic fields; Magnets; Physics - Mesoscale and Nanoscale Physics; Remanence; Symmetry; Thin films; Transport properties
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2309.00568

Observations of the anomalous Hall effect in RuO\(_2\) 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 RuO\(_2\) is excluded by symmetry for the Néel vector pointing along the zero-field [001] easy-axis. Guided by a symmetry analysis and ab initio calculations, a field-induced reorientation of the Néel 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 RuO\(_2\) 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 \(H_{\rm c} \simeq\) 55 T that was inaccessible in earlier studies, but is consistent with the expected Néel-vector reorientation field.