Cross-shaped nanostructures for the study of spin to charge inter-conversion using spin-orbit coupling in non-magnetic materials

Abstract

Several spin–orbit effects allow performing spin to charge interconversion due to the spin Hall effects or the spin-momentum locking at Rashba interfaces and topological insulator surface states. Here, we focus on how these interconversions can be made electrically, using three different cross-shaped nanostructures. We apply the measurement configurations to the case of the spin Hall effect in Pt using CoFe electrodes to detect or inject spins. Both the direct and inverse spin Hall effects can be detected, with spin Hall signals up to two orders of magnitude higher than that of nonlocal measurements in metallic lateral spin valves, and with a much simpler fabrication protocol. We compare the respective signal amplitude of the three proposed geometries. Finally, we show that finite element method calculations allow extracting the spin Hall angle and the spin diffusion length of Pt from these measurements.