Antiferromagnetic enhancement of spin transport in metallic exchange-biased Co/FeMn/Pt structures

The conversion of spin and charge currents is a necessary condition for spintronic devices, which is determined by spin pumping and the inverse spin-Hall effect (ISHE). In the past decade, ISHE and spin pumping have been actively studied in ferromagnet/normal metal heterostructures. Recently, antiferromagnets were found to enhance spin pumping as they exhibit exchange-enhanced dynamics, high spin–orbit coupling, and the absence of a stray field. In this paper, we propose methods for evaluating the inverse spin Hall effect induced by using microwave-driven spin pumping as a spin current generator. We studied ISHE via spin pumping in Pt/Co(10)/FeMn(x)/Pt samples (x = 0, 5, 10, 15 nm), confirmed by angle-dependent ISHE measurements. We also clarified other spin rectification effects and found that spin pumping dominates in all samples. The contribution due to the pure spin current, detected using the inverse spin Hall effect in a normal metal, was calculated. It was found that the amplitude of the observed signal caused by the spin current flowing through Co(10)/FeMn(5)/Pt(1.5) is two times higher than a similar signal in the structure without an antiferromagnetic layer Co(10)/Pt(2).