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arXiv · 2310.16907

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

Edgar Galindez-Ruales·Rafael Gonzalez-Hernandez·Christin Schmitt·Shubhankar Das·Felix Fuhrmann·Andrew Ross·Evangelos Golias·Akashdeep Akashdeep·Laura Lünenbürger·Eunchong Baek·Wanting Yang·Venkata Krishna·Rodrigo Jaeschke-Ubriego·Libor Šmejkal·Jairo Sinova·Avner Rothschild·Chun-Yeol You·Gerhard Jakob·Mathias Kläui
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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 N\'eel 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 N\'eel 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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Edgar Galindez-Ruales, Rafael Gonzalez-Hernandez, Christin Schmitt, Shubhankar Das, Felix Fuhrmann, Andrew Ross, Evangelos Golias, Akashdeep Akashdeep, Laura Lünenbürger, Eunchong Baek, Wanting Yang, Venkata Krishna, Rodrigo Jaeschke-Ubriego, Libor Šmejkal, Jairo Sinova, Avner Rothschild, Chun-Yeol You, Gerhard Jakob, Mathias Kläui. 2023-10-25. Revealing the Altermagnetism in Hematite via XMCD Imaging and Anomalous Hall Electrical Transport. https://doi.org/10.1002/adma.202505019

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