Spin-current vortices in current-perpendicular-to-plane nanoconstricted spin valves

Abstract

The charge and spin diffusion equations, taking into account spin-flip and spin-transfer torque, were numerically solved using a finite element method in complex noncollinear geometry with strongly inhomogeneous current flow. As an illustration, spin-dependent transport through a nonmagnetic nanoconstriction, separating two magnetic layers was investigated. Unexpected results such as vortices of spin-currents in the vicinity of the nanoconstriction were obtained. The angular variations of magnetoresistance and spin-transfer torque are strongly influenced by the structure geometry.