Roles of Joule heating and spin-orbit torques in the direct current induced magnetization reversal

Abstract

Current-induced magnetization reversal via spin-orbit torques (SOTs) has been intensively studied in heavy-metal/ferromagnetic-metal/oxide heterostructures due to its promising application in low-energy consumption logic and memory devices. Here, we systematically study the function of Joule heating and SOTs in the current-induced magnetization reversal using Pt/Co/SmOx and Pt/Co/AlOx structures with different perpendicular magnetic anisotropies (PMAs). The SOT-induced effective fields, anisotropy field, switching field and switching current density (Jc) are characterized using electric transport measurements based on the anomalous Hall effect and polar magneto-optical Kerr effect (MOKE). The results show that the current-generated Joule heating plays an assisted role in the reversal process by reducing switching field and enhancing SOT efficiency. The out-of-plane component of the damping-like-SOT effective field is responsible for the magnetization reversal. The obtained Jc for Pt/Co/SmOx and Pt/Co/AlOx structures with similar spin Hall angles and different PMAs remains roughly constant, revealing that the coherent switching model cannot fully explain the current-induced magnetization reversal. In contrast, by observing the domain wall nucleation and expansion using MOKE and comparing the damping-like-SOT effective field and switching field, we conclude that the current-induced magnetization reversal is dominated by the depinning model and Jc also immensely relies on the depinning field.

Tailoring Multilevel‐Stable Remanence States in Exchange‐Biased System through Spin‐Orbit Torque

“…[ 31 ] Thus, not only the magnetization but also the exchange‐bias are reversed by SOT. Due to the deterministic magnetization switching by SOT, [ 11–13,26–30 ] only the up (down) magnetized domain could be switched to opposite direction under a positive (negative) current pulse with an assistance field of + H x , as schematically shown in Figure 1e,f. Thereby, concurrent switching of FM magnetization and AFM interfacial spins by SOT can be realized.…”

“…The SOT effect has been demonstrated as an efficient way to switch the magnetization of FM or AFM, and was widely investigated owing to its potential applications in magnetic random access memory (MRAM) and other spintronic devices. [ 11–13,26–30 ] In particular, in HM/FM/AFM trilayers, Lin et al recently reported that the hysteresis loops between positively and negatively single‐biased loops could be manipulated by SOT through switching the FM spins and AFM interfacial spins completely and simultaneously with magneto–optical Kerr techniques. [ 31 ] It provides an effective approach to manipulate the FM magnetization and AFM interfacial spins in HM/FM/AFM trilayers by SOT.…”

Orbitally dominated Rashba-Edelstein effect in noncentrosymmetric antiferromagnets

“…Such spin-dynamics simulations could clarify as well the role of the non-staggered, homogeneous components for the switching and the influence of Joule heating, inherently present in all experiments. It was shown recently that Joule heating plays an essential role as it drastically decreases the required switching field and enhances the spin–orbit torque efficiency 49 . Also for MnAu, it was lately concluded that Joule heating can provide a sufficient thermal activation for switching processes 31 .…”

Interplay between Spin‐Orbit Torques and Dzyaloshinskii‐Moriya Interactions in Ferrimagnetic Amorphous Alloys

“…Thermal effects in currentinduced spin-orbit torque switching have been extensively studied in the literature and it was shown that it can lead to a reduced value of the in-plane field necessary to initially break the system symmetry or induce a crossing of the compensation point in synthetic ferrimagnets. [34][35][36] The emergence of an intermediate resistance state when sweeping the current was observed in the SOT switching experiments for certain CoGd structures. As seen in Figure 2c for Pt/Co 73 Gd 27 /W, an intermediate resistance plateau appeared in the current switching hysteresis loops at low in-plane magnetic field.…”