Revealing the Altermagnetism in Hematite via XMCD Imaging and Anomalous Hall Electrical Transport

Abstract

Altermagnets are a class of magnetic materials that exhibit unconventional transport properties, such as an anomalous Hall effect, despite having compensated sublattice magnetic moments. In this study, we report fundamental experimental evidence of the altermagnetic nature of hematite ($\alpha$-\ch{Fe2O3}), combining electrical transport with advanced XPEEM imaging with linear and circular dichroism contrast. Our measurements directly visualize the Néel vector's coupling to the crystal orientation, confirming hematite's altermagnetic order and its symmetry-driven transport behavior. Transport measurements reveal an anisotropic AHE with a pronounced crystal orientation dependence, including a sign inversion for specific Néel vector alignments. Supported by first-principles theoretical calculations, we explain how the interplay between collinear spin and crystal symmetry breaking drives the observed anomalous Hall effect. These findings establish hematite as an altermagnet, paving the way for experimental identification of altermagnetic materials and their integration into spintronic technologies.

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Cited by in corpus (7)

• Altermagnetic splitting of magnons in hematite ($\alpha$-Fe${}_2$O${}_3$)
• Revealing the Altermagnetism in Hematite via XMCD Imaging and Anomalous Hall Electrical Transport
• Anomalous-Hall Neel textures in altermagnetic materials
• Electric and spin current vortices in altermagnets
• Matter with apparent and hidden spin physics
• X-ray magnetic circular dichroism originating from the $T_z$ term in collinear altermagnets under trigonal crystal field
• Tuning spin currents in collinear antiferromagnets and altermagnets