Anisotropic magnetoresistance driven by surface spin-orbit scattering

In a bilayer consisting of an insulator and a ferromagnetic metal (FM), interfacial spin-orbit scattering leads to spin mixing of the two conducting channels of the FM, which results in an unconventional anisotropic magnetoresistance (AMR). We theoretically investigate the magnetotransport in such bilayer structures by solving the spinor Boltzmann transport equation with the generalized Fuchs-Sondheimer boundary condition that takes into account the effect of spin-orbit scattering at the interface. We find that the new AMR exhibits a peculiar angular dependence which can serve as a genuine experimental signature. We also determine the dependence of the AMR on film thickness as well as resistivity spin asymmetry of the FM.