Estimation of thermal stability factor and intrinsic switching current from switching distributions in spin-transfer-torque devices with out-of-plane magnetic anisotropy

We performed macromagnetic simulations of switching statistics in spin-transfer-torque devices with out-of-plane magnetic anisotropy and thermal stability factors ranging from Δ = 21 to Δ = 279. We compared our results of the simulated switching probabilities in low-currents (read-disturb) and long-times (thermally activated) limits with the predictions of several existing models that predict the switching probability to be proportional to (1 − I/Ic0)n (Eq. 3), with exponent n varying from n = 1 to n = 2.2. We found that the best match to the simulated data in these two limits is obtained with values of n ≈ 1.76, when currents are limited to ∼ 0.6-0.8 Ic0.