Current Dependence of Spin Torque Switching Barrier

The current dependence of the switching barrier for spin torque switching of an in-plane magnetized ferromagnet was studied. Two scaling currents, I_{c}$ and I_{c}^{*}(>I_{c}), were introduced to distinguish the magnetization stability. In the low-current region I<I_{c}, the switching barrier is linear to the current with another scaling current \tilde{I}_{c}, while such linear scaling does not hold in the high-current region I_{c} < I < I_{c}^{*}. The linear scaling is valid for the high temperature and the long current pulse duration time.