With the advancement of antiferromagnetic (AFM) spintronics, magnetic materials with diverse magnetic structures have garnered widespread attention. Of particular interest are “unconventional magnets”, which simultaneously exhibit AFM configurations while displaying properties reminiscent of ferromagnets (FMs). Thus, unconventional magnets promise to combine the advantages of both FM and AFM materials, offering, e.g., high storage capacity, low power consumption, electrical manipulation and read-out, and ultrafast dynamics. The rapid evolution of the emerging field of unconventional magnetism has inevitably engendered some degree of conceptual ambiguity and uncertainty, particularly regarding the intricate entanglement between spin-split-AFM (including altermagnets) and anomalous-Hall-AFM. In this talk, we start with symmetry theory describing magnetic geometry—spin group theory—to discuss the symmetry design strategies and material pools for these two types of unconventional magnets, aiming to inspire further exploration in the field of unconventional magnetism. We also introduce a homemade online program, FINDSPINGROUP (https://findspingroup.com/), which is applied to diagnose the symmetry classification of magnetic materials.
References
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