We propose an effect whereby an electric current along the interface between a ferromagnetic and normal metal leads to injection of pure spin current into the normal metal, if the magnetization direction in the ferromagnet varies spatially along the direction of current. For the specific example of a ferromagnetic spin spiral, we compute the inverse spin Hall effect voltage this spin current gives rise to when injected into a Pt layer. Furthermore, we show that this pure spin current leads to modification of the parameters that govern spin transfer and current-driven domain-wall motion, which can be used to tune the latter in layered magnetic systems. This effect in principle enables in situ control over the location, magnitude, and polarization of spin-current injection in devices.

• Received 7 January 2013

DOI:https://doi.org/10.1103/PhysRevB.88.064417