Pedestrian approach to altermagnets

Altermagnets have recently emerged as a new class of magnetic materials sharing properties of both antiferromagnets and ferromagnets. Despite very small net magnetization, they show phenomena usually associated with ferromagnetism, such as the Faraday, Kerr and Anomalous Hall effects, resulting from the relativistic spin-orbit coupling, as well as the spin splitting of electron bands and Spin Hall Effect of non-relativistic origin. Spin space groups and magnetic multipoles are used to explain the properties of altermagnets. I will give a pedagogical introduction into a symmetry analysis of altermagnets that makes use of an antiferromagnetic order parameter [1]. This time-honored approach applies to all physical phenomena observed in altermagnets with collinear and non-collinear spin orders.

References:

[1] M. Mostovoy, Appl. Phys. Lett. 127, 060501 (2025).