Dissipation properties of altermagnetic versus ferromagnetic Hall devices

Two “Hall-like” effects are occurring in ferromagnets: the Anomalous Hall effect (AHE) and the Planar Hall effect (PHE) [1]. The former is analogous to the classical Hall effect and is defined by an antisymmetric conductivity matrix, while the latter is defined by a symmetric conductivity matrix. The difference is fundamental, as it is based on time-invariance symmetry breaking at the microscopic scale. We study theoretically and experimentaly the Hall-like current generated in both cases, together with the electric power that can be extracted from a load resistance. We have performed the experimental study, based on GdCo ferrimagnet [3] and Si3Mn5 altermagnet [4] and NiFe 3d-ferromagnet. The difference of the dissipated power as a function of the Hall angle between AHE and PHE gives an experimental criteria for the identification of the two effects in non-saturated altermagnet. [1] J.-E. Wegrowe et al., Phys. Rev. B 110, 024412 (2024), [2] F. Faisant, M. Creff, J.-E. Wegrowe J. Appl. Phys. 129, 144501 (2021) [3] D. Lacour, M. Hehn, Min Xu, J.-E. Wegrowe, J. Appl. Phys. 135, 193903 (2024) [4] M. Leiviskä et al.M. Leiviskä et al. Phys. Rev. B 109, 224430 (2024).