Synthetic antiferromagnetic layer based on Pt/Ru/Pt spacer layer with 1.05 nm interlayer exchange oscillation period for spin-orbit torque devices

We investigated interlayer exchange coupling through Pt/Ru/Pt and Pt/Ru multilayers as candidates of nonmagnetic spacer layers in the synthetic antiferromagnetic (AF) layer, which is available for studying AF spintronics using current-induced spin-orbit torque (SOT) switching originating from the spin Hall effect. The AF interlayer exchange coupling with the oscillation period of Lambda(2) similar to 1.05nm was observed even for the face-centered cubic (fcc) Pt (t(Pt))/hexagonal Ru/fcc Pt (t(Pt)) nonmagnetic spacer layer structures in the wide range of both Pt and total nonmagnetic spacer layer thicknesses (0 <= t(Pt) <= 0.8 nm, 1.0 <= t(total) <= 2.3 nm), which would be useful for the systematic investigation of the SOT on the AF structure. Moreover, we observed the disappearance of the one oscillation period (Lambda(1) similar to 1.65 nm) in the case of Pt(111)/Ru(0001) and Pt(111)/Ru(0001)/Pt(111) spacer layers, whereas the existence of two oscillation periods of AF interlayer exchange coupling (Lambda(1) similar to 1.65nm and Lambda(2) similar to 1.05 nm) in the case of Ru spacer layer was observed. We expect that the Pt/Ru/Pt spacer layer with the oscillation period of Lambda(2) similar to 1.05 nm will pave a way to the AF spintronics based on the multilayer systems. Published under an exclusive license by AIP Publishing.