Experimental Evidence of Néel-Order-Driven Magneto-optical Kerr Effect in an Altermagnetic Insulator
Abstract
The magneto-optical Kerr effect (MOKE) is investigated in hematite, a collinear antiferromagnetic insulator, across a broad wavelength spectrum. By combining the optical measurements with magnetometry results, we unambiguously demonstrate that the Néel-order contribution dominates the MOKE signal, while contributions from net magnetization and external magnetic fields are negligible. This conclusion is quantitatively supported by first-principles calculations, and qualitatively by a symmetry analysis that the Néel contribution appears at the first order in spin-orbit coupling while the magnetization contribution starts only at the third order. This study clarifies the altermagnetic origin of the pronounced MOKE in hematite, underscoring the potential of altermagnets as a promising new class of magneto-optical materials.
Fields of Study & Subjects
Iron oxide chemistry and applications
Magneto-Optical Properties and Applications
Geomagnetism and Paleomagnetism Studies
Publication details
- Journal / source
- Physical Review Letters
- Publisher
- American Physical Society (APS)
- Volume
- 136
- Issue
- 3
- Pages
- 036701–036701
- Publication date
- 2 January 2026
- Language
- EN