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 τ=0 K (I_c^0K) are then compared with that at τ=τ₀ (I_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_c^0K, not I_c0, must be known since I_c0 has temperature dependence.