Magnetization switching by spin torque using subnanosecond current pulses assisted by hard axis magnetic fields

We have induced magnetization switching by spin transfer in pillar-shaped spin valves using nanosecond-scale current pulses combined with hard axis fields. Switching events requiring 100 ps pulses were obtained. In comparison with the switching induced by a single current pulse, biasing the device with a hard axis field decreases the pulse duration needed for error-free switching. The reduction of the cost in pulse amplitude scales with the magnitude of the applied field, and can be quantitatively understood from micromagnetic simulations and macrospin arguments taking into account the thermal fluctuations. (c) 2006 American Institute of Physics.