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arXiv · 2407.11836

Magnetic memory and distinct spin populations in ferromagnetic Co3Sn2S2

Charles Menil·Brigitte Leridon·Antonella Cavanna·Ulf Gennser·Dominique Mailly·Linchao Ding·Xiaokang Li·Zengwei Zhu·Benoît Fauqué·Kamran Behnia
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Abstract

Co3Sn2S2, a ferromagnetic Weyl semi-metal with Co atoms on a kagome lattice, has generated much recent attention. Experiments have identified a temperature scale below the Curie temperature. Here, we find that this magnet keeps a memory, when not exposed to a magnetic field sufficiently large to erase it. We identify the driver of this memory effect as a small secondary population of spins, whose coercive field is significantly larger than that of the majority spins. The shape of the magnetization hysteresis curve has a threshold magnetic field set by the demagnetizing factor. These two field scales set the hitherto unidentified temperature scale, which is not a thermodynamic phase transition, but a crossing point between meta-stable boundaries. Global magnetization is well defined, even when it is non-uniform, but drastic variations in local magnetization point to a coarse energy landscape, with the thermodynamic limit not achieved at micrometer length scales.

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Charles Menil, Brigitte Leridon, Antonella Cavanna, Ulf Gennser, Dominique Mailly, Linchao Ding, Xiaokang Li, Zengwei Zhu, Benoît Fauqué, Kamran Behnia. 2024-07-16. Magnetic memory and distinct spin populations in ferromagnetic Co3Sn2S2. https://doi.org/10.1038/s41535-025-00739-6

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