Joule heating and temperature effects on current-induced magnetization switching in perpendicularly magnetized Pt/Co/C structures

Abstract

We study the temperature (T) dependence of the anisotropy field (Hk), switching field (Hsw), saturation magnetization (Ms), spin–orbit torques (SOTs), and critical switching current density (Jc) as well as Joule heating effect in the current-induced magnetization switching using Pt/Co/C stacks with perpendicular magnetic anisotropy. The results show that Hk remains roughly constant and Jc gradually decreases as T increases. The increased damping-like-SOT-induced effective field per unit current density (ΔHDL/Je) with T increasing reveals the enhanced SOT efficiency at higher T. However, the calculated ΔHDL at Jc is still a relatively small magnitude and cannot overcome the large Hk. In contrast, a significantly reduced Hsw was observed with the current or T increasing. It indicates that the magnetization switching is dominated by a depinning model. Only when the out-of-plane component of the ΔHDL overcomes Hsw, the magnetization realizes a full reversal. Especially, both ΔHDL and Hsw codetermine Jc. Meanwhile, T or current-generated Joule heating plays an assisted role in the switching by increasing SOT efficiency and decreasing Hsw. Moreover, our results also show that the enhanced ΔHDL/Je at higher T is determined by the reduced Ms and the spin Hall angle keeps invariable at different T. These findings could provide a new perspective towards improving the switching efficiency in SOT-based spintronic devices.