Micromagnetic study of switching in ring-shaped spin valve structures

In this paper, we present a micromagnetic simulation of magnetization reversal in a ring-shaped pseudo-spin valve (PSV), consisting of a storage layer made of permalloy (3 nm), a pinned layer of Co (3 nm), and a Cu spacer layer (3 nm). The transition between the two vortex stable states of the storage layer is modeled by applying a write current pulse. This pulse generates an Oersted field and an effective exchange field due to spin torque. The switching mechanism is investigated for different amplitude and duration of the current pulse, and the conditions for the desired switching behavior is discussed. Ideal switching behavior is obtained for a write pulse of at least 3 ns.