Switching by sub-nanosecond current pulses using spin angular momentum transfer

The spin-transfer switching performance of spin valve nanopillars composed of PtMn17.5/CoFe1.8/Ru8/CoFe2/Cu3.5/CoFe1/NiFe1.8 is measured in this study at current pulse durations of 0.1-10 ns and temperature range of 40-300 K. Results show that the switching speed accelerates marginally when cooling, with a slightly better reproducibility at low temperature. A static field applied along the hard axis however can drastically accelerate the switching, increasing the efficiency of both DC current and pulsed current. This can be attributed to the influence of a noncollinear initial state, and becomes significant when the field is greater than typically a quarter of the anisotropy field.