Even-in-magnetic field part of transverse resistivity as a probe of magnetic transitions

The component of the resistivity tensor ρij corresponding to voltage transverse to both an applied current and a magnetic field can be separated into odd and even parts with respect to the applied magnetic field. The former contains information, for example, about the ordinary or anomalous Hall effect. The latter is often ascribed to experimental artifacts and ignored. Here, we show that upon suppressing these artifacts in carefully controlled experiments, useful information remains. We first investigate the well-explored ferromagnet CoFeB, where the even part of ρyx contains a contribution from the anisotropic magnetoresistance, which we confirm by Stoner–Wohlfarth modeling. We then apply our approach to magnetotransport measurements of Mn5Si3 thin films, which undergo a transition from non-collinear to an altermagnetic collinear state. In this material, the even part of the transverse signal is sizable only in the low-spin-symmetry phase below ≈80 K. Transverse resistivity measurements thus offer a simple and readily available probe of magnetic order transitions.