Switching effect in ferromagnetic metallic junctions

Mechanisms are determined for homogeneous current-induced switching in ferromagnetic metallic junctions of the spin-valve type. The spin flux is perpendicular to the junction surface and is directed from the pinned layer to the free one. The switching is due to the joint action of two mechanisms: (i) current-induced surface torque and (ii) current-induced injection of nonequilibrium longitudinal spins into the free-layer bulk. Both mechanisms lead to the instability and reorientation of magnetization; however, only the injection mechanism can stabilize the switching.