Magnetization reversal triggered by spin-polarized current in magnetic nanowires

It is shown experimentally that a pulsed current driven through a Ni nanowire provokes an irreversible magnetization reversal at a field differing from the spontaneous switching field H-sw by DeltaH of as much as 40% of H-sw. The state of the magnetization is assessed by anisotropic magnetoresistance measurements carried out on single, isolated nanowires with and without spin polarizer (Co/Cu multilayers). The parameter DeltaH is studied as a function of the angle theta between the applied field and the wire. A shift of about 90 degrees between both profiles DeltaH (theta) with and without spin polarizer shows that the observed effect is related to the spin polarization of the current. The results are interpreted with a model of generalized Landau-Lifshitz-Gilbert equation with spin-polarized current.