Anomalous Hall magnetoresistance in a ferromagnet.

The anomalous Hall effect, observed in conducting ferromagnets with broken time-reversal symmetry, offers the possibility to couple spin and orbital degrees of freedom of electrons in ferromagnets. In addition to charge, the anomalous Hall effect also leads to spin accumulation at the surfaces perpendicular to both the current and magnetization direction. Here, we experimentally demonstrate that the spin accumulation, subsequent spin backflow, and spin–charge conversion can give rise to a different type of spin current-related spin current related magnetoresistance, dubbed here as the anomalous Hall magnetoresistance, which has the same angular dependence as the recently discovered spin Hall magnetoresistance. The anomalous Hall magnetoresistance is observed in four types of samples: co-sputtered (Fe1−xMn x )0.6Pt0.4, Fe1−xMn x /Pt multilayer, Fe1−xMn x with x = 0.17–0.65 and Fe, and analyzed using the drift-diffusion model. Our results provide an alternative route to study charge–spin conversion in ferromagnets and to exploit it for potential spintronic applications. Magnetoresistance in ferromagnetic materials and heterostructures have been enabling advanced understanding of electron transport in solids, as well as new concepts for applications. Here the authors demonstrate a different type of magnetoresistance arising from anomalous Hall effect associated spin–charge mutual conversion.