Current-driven switching of magnetic layers - art. no. 064424

The switching of magnetic layers is studied under the action of a spin curr ent in a ferromagnetic metal-nonmagnetic metal-ferromagnetic metal spin val ve. We find that the main contribution to the switching comes from the none quilibrium exchange interaction between the ferromagnetic layers. This inte raction defines the magnetic configuration of the layers with minimum energ y and establishes the threshold for a critical switching current. Depending on the direction of the critical current, the interaction changes sign and a given magnetic configuration becomes unstable. To model the time depende nce of the switching process, we derive a set of coupled Landau-Lifshitz eq uations for the ferromagnetic layers. Higher order terms in the nonequilibr ium exchange coupling allow the system to evolve to its steady-state config uration.