Temperature dependence of spin-orbit torques across the magnetic compensation point in a ferrimagnetic TbCo alloy film

Abstract

The temperature dependence of spin-orbit torques (SOTs) and spin-dependent transport parameters is measured in bilayer Ta/TbCo ferrimagnetic alloy films with bulk perpendicular magnetic anisotropy. We find that the dampinglike (DL)-SOT effective field diverges as temperature is swept through the magnetic compensation temperature (TM), where the net magnetization vanishes due to the opposing contributions from the Tb and Co sublattices. We show that DL-SOT scales with the inverse of the saturation magnetization (Ms), whereas the spin-torque efficiency is independent of the temperature-dependent Ms. Our findings provide insight into spin transport mechanisms in ferrimagnets and highlight low-Ms rare-earth/transition-metal alloys as promising candidates for SOT device applications.