Effects of nonmagnetic impurity scattering in a ferromagnet with inhomogeneous magnetization

Abstract

The interaction between an electric current and local magnetization in a ferromagnetic system where the magnetization varies continuously has recently been a subject of interest. When there is no impurity scattering, an adiabatic process occurs; that is, the spins of conduction electrons follow the direction of the local magnetization. In this work, we investigated the effects of impurity scattering on the interaction between the spins of conduction electrons and the local magnetization. To do this, we consider an infinite spin spiral in one dimension. In the absence of impurity scattering, the spins of conduction electrons follow the direction of the sum of those of the local magnetizations and the direction of an effective-field arising from the gradient of the magnetization in the spin spiral structure. When impurity scattering was taken into account, we found a quantum-mechanical oscillation of spin density around the local magnetization. As a result, the spin current could deviate from the adiabatic spin current configuration.