Controllable Spin-Orbit Torque Efficiency in Pt/Co/Ru/Co/Pt Multilayers with Interlayer Exchange Couplings

The magnetization manipulation by the current-induced spin-orbit torque opens a prospect for energy-efficient spintronic applications. Here, we investigate controllable spin-orbit torques (SOTs) realized by interlayer exchange coupling (IEC) in Pt/Co/Ru/Co/Pt stacks. The interlayer magnetization realignments originate from the competition between itinerant electron diffusion and current-induced spin current relaxation, and it is revealed that the long-ranged interlayer antiparallel orders exist with a Ru spacer thickness of 2.3 nm. The current-induced hysteresis-loop-shift method is used to assess the H-z(eff)/J depending on the different spacer thicknesses. The loop shift distributions are revealed with the H-z(eff) phase diagrams to characterize the difference between FM-IEC and AFM-IEC. Combining with micromagnetic simulations, a possible transition mechanism of H-z(eff)/J is discussed by combining magnetization switching with the in-plane bias field in IEC systems. This work demonstrates that the spin current realigned IEC mechanism can efficiently control the SOTs in both ferromagnetic and antiferromagnetic multilayers.

Automated summary

The study investigates controllable spin-orbit torques realized by interlayer exchange coupling in Pt/Co/Ru/Co/Pt stacks, revealing the existence of long-ranged interlayer antiparallel orders. By using the current-induced hysteresis-loop-shift method, the differences in loop shift distributions depending on spacer thickness are characterized to show a possible transition mechanism of H-z(eff)/J in IEC systems.