Inspection of intrinsic critical currents for spin-transfer magnetization switching by low-temperature measurements

Low-temperature measurements of spin-transfer magnetization switching are carried out. The extrapolated critical currents at /spl tau/=0 K (I/sub c//sup 0K/) are then compared with that at /spl tau/=/spl tau//sub 0/ (I/sub c0/) as well as with switching currents measured by ns-pulsed currents. To estimate currents for nano-second writing where no thermal switching happens, I/sub c//sup 0K/, not I/sub c0/, must be known since I/sub c0/ has temperature dependence.