Domain-wall dynamics and spin-wave excitations with spin-transfer torques

A spin torque based on the generalized angular momentum transfer mechanism was proposed. The spin torque was incorporated into Landau-lifshitz-Gilbert equation to describe spin wave excitations and domain-wall distortion and propagation. It was found that the spin torque had form identical to that in magnetic multilayers for spatially nonuniform magnetization. The spin torque can generate bulk and surface spin excitations for point-contact experiments. The spin current excite surface or interface spin modes due to occurence of current density near the interface between the nonmagnetic probe and magnetic layer.