Ferrimagnetic insulators promise low-power and high-speed spintronic applications, thanks to their insulating nature and fast dynamics near compensation points. In a ferrimagnetic insulator/heavy metal heterostructure, we investigate field- and current-induced magnetization switching at various temperatures and observe distinct magnetization switching behaviors owing to spin–orbit torque (SOT) and heating effect. We have realized SOT switching across the magnetization compensation temperature and discovered that the SOT switching is strongly heat-assisted: the temperature is always above the compensation temperature while the SOT switching happens in our case. Moreover, we show that the SOT efficiency is strongly magnetization-dependent by characterizing the current dependence of SOT efficiency and explaining the anomalous SOT switching back phenomena in the presence of a titled external field. Our results reveal the critical role of Joule heating on the dynamics of magnetic insulators and pave the way for the application of spintronic devices based on magnetic insulators.

The damping parameter 𝛼 FM in ferrimagnets defined by following the conventional practice for ferromagnets is known to be strongly temperature dependent and diverge at the angular momentum compensation temperature, where the net angular momentum vanishes. However, recent theoretical and experimental developments suggest that the damping parameter can be defined in such a way, which we denote by 𝛼 FiM , that it is free of the diverging anomaly at the angular momentum compensation point and is little dependent on temperature. To further understand the temperature dependence of the damping parameter in ferrimagnets, we analyze several data sets from literature for gadolinium iron garnet (Gd3Fe5O12) by using the two different definitions of the damping parameter. Using two methods to estimate the individual sublattice magnetizations, which yield results consistent with each other, we found that in all the used data sets, the damping parameter 𝛼 FiM does not increase at the angular compensation temperature and shows no anomaly whereas the conventionally defined 𝛼 FM is strongly dependent on the temperature.

No abstract