Current-induced switching of magnetic tunnel junctions: Effects of field-like spin-transfer torque, pinned-layer magnetization orientation and temperature

We study current-induced switching in magnetic tunnel junctions (MTJs) in the presence of a field-like spin-transfer torque and titled pinned-layer magnetization in the high current limit at finite temperature. We consider both the Slonczewski and field-like torques with coefficients $a_J$ and $b_J $, respectively. At finite temperatures, $\sigma= b_J/a_J = \pm1$ leads to a smaller mean switching time compared that with $\sigma = 0$. The reduction of switching time in the presence of the field-like term is due to the alignment effect (for $\sigma > 0$) and the initial torque effect.