Ultrafast switching of a nanomagnet by a combined out-of-plane and in-plane polarized spin current pulse

We report on spin valve devices that incorporate both an out-of-plane polarizer (OPP) to quickly excite spin torque (ST) switching and an in-plane polarizer/analyzer (IPP). For pulses <200 ps, we observe reliable precessional switching due largely to ST from the OPP. Compared to a conventional spin valve, for a given current amplitude from ∼2 to 3 times the zero-thermal-fluctuation critical current (Ic0), the addition of the OPP can decrease the pulse width necessary for switching by a factor of 10 or more. The effect of the IPP also has beneficial ST consequences for the short pulse switching behavior.