Time-domain studies of very-large-angle magnetization dynamics excited by spin transfer torques

I. N. Krivorotov, N. C. Emley, R. A. Buhrman, D. C. Ralph
2008 Physical Review B  
We describe time-domain measurements which provide new information about the large-angle nonlinear dynamics of nanomagnets excited by spin-transfer torque from a spin-polarized current. Sampling-oscilloscope measurements, which average over thousands of experimental time traces, show that the mean reversal time for spin-transfer-driven magnetic switching has a step-like dependence on magnetic field, because an integer number of precession cycles is required for reversal. Storage-oscilloscope
more » ... age-oscilloscope measurements of individual experimental traces reveal non-periodic large-amplitude resistance variations at values of magnetic field and current in a crossover region between the regimes of spin-transfer-driven switching and steady-state precession. We also observe directly the existence of time-dependent switching, on the nanosecond scale, between different precessional modes and between a precessional mode and a static state, at particular values of magnetic field and current bias.
doi:10.1103/physrevb.77.054440 fatcat:lgrbflclrncf5ciupc2wyys5nu