Moving of domain walls by spin polarized current

Summary form only given. On the base of a phenomenological theory we considered here a model of a three layer magnetic junction, consisting of two ferromagnetic layers (electrodes) separated by a nonmagnetic ultrathin layer (spacer). One of the electrodes has a magnetization pinned parallel to interfaces along z-axis and the other one is free and may contain a magnetic domain structure. An electrical current may be present that transports carriers through the spacer from the pinned layer to the free one. No spin-dependent surface scattering exists and current affects the magnetic state of the free layer due to injection of the spins only. We found a solution of continuity equations for carriers having up and down spins that satisfy boundary conditions at interfaces of the free electrode. Current dependent density and magnetization of the injected spins were calculated. This allows us to find the current dependent energy of exchange interaction between carriers and localized spins (s-d interaction). Experiments were conducted with three-layer tunnel junctions of a type Ni/S/Fe, where S is a spacer of diamond-like carbon or polyimide films with thickness /spl sim/8 nm and cross section /spl sim/100 /spl mu/m/sup 2/. The observations from the theoretical and experimental studies described here may be considered as a manifestation of domain walls moving by a spin-polarized current.