Reply to 'Comment on 'Metastable state in a shape-anisotropic single-domain nanomagnet subjected to spin-transfer torque'' [Appl. Phys. Lett. 105,116101 (2014)]

摘要

In his Comment, Bazaliy seems to have raised four issues: (1) the metastable state discussed in our paper is a potential energy maximum and hence always unstable/ irrelevant; (2) if one considers the magnetization dependence of the so-called "efficiency factor" g explicitly, then the in-plane component of the spin-transfer torque alone could stabilize the metastable state, without any need for the out-of-plane component; (3) some of the stability properties of the metastable state in the presence of thermal noise could have been inferred from stability diagrams and phase portraits, without perhaps the need for any stochastic Landau-Lifshitz-Gilbert simulations; and (4) the minimum switching current needed to avoid getting trapped in the metastable state is too high for technological applications. We address each of these issues below: First, the metastable state is a potential energy maximum only when no spin-polarized current flows through the magnet. In the presence of current flow (which is the situation we discuss), it cannot be viewed as a potential energy maximum because the non-conservative component of the spin-transfer-torque, resulting from flow of the current, cannot be captured within any potential energy framework. Therefore, this state is not always unstable, since the potential energy argument is untenable.