Electrical Tuning of Ferrimagnetic Spin Alignment Angle and Compensation Temperature in Pt/IrMn3/CoGd Multilayers

Abstract

Compensation temperature (T M) is a characteristic parameter for a ferrimagnetic (FIM) material that requires careful consideration in the functional applications of FIM spintronics. Attempts at precise and localized control of T M have remained rare and challenging, but apparently a worthy issue for the expansion of spintronics to include FIMs. Conventional approaches such as thermal annealing or ion injection suffer from limited spatial selectivity and switching speed. Here, we show a novel route to control the T M of FIM by manipulating the alignments of the constituent spins through spin-orbit torque (SOT)-controlled exchange couplings with adjacent antiferromagnets. At the interface between antiferromagnetic IrMn3 and FIM CoGd multilayers, it was found that the antiferromagnet established firm exchange couplings with Co atoms, but negligible couplings with Gd. Such selective coupling modified the traditionally known collinear antiparallel arrangement of CoGd spins into a noncollinear spiral spin configuration, and the T M was found to correspondingly change significantly. Additionally, precise tuning of FIM properties through the modulation of SOT amplitude and application time was demonstrated, establishing an efficient electrical pathway for controlling the compensation phenomena in ferrimagnetic systems.