Theory of Spin Torque Assisted Thermal Switching of Single Free Layer

The spin torque assisted thermal switching of the single free layer was studied theoretically. Based on the rate equation, we derived the theoretical formulas of the most likely and mean switching currents of the sweep current assisted magnetization switching, and found that the value of the exponent $b$ in the switching rate formula significantly affects the estimation of the retention time of magnetic random access memory. Based on the Fokker-Planck approach, we also showed that the value of $b$ should be two, not unity as argued in the previous works.