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

TL;DR

This paper introduces three cross-shaped nanostructures to electrically detect spin to charge inter-conversions via spin-orbit effects, demonstrating enhanced signals and simplified fabrication for studying spin Hall effects in platinum.

Contribution

It presents novel nanostructure geometries for efficient electrical detection of spin Hall effects, enabling accurate extraction of spin parameters with improved signal strength.

Findings

Spin Hall signals up to two orders of magnitude higher than traditional methods

Comparison of three geometries reveals differences in signal amplitudes

Finite element modeling accurately extracts spin Hall angle and diffusion length

Abstract

Several spin-orbit effects allow performing spin to charge inter-conversion: the spin Hall effects, the Rashba effect, or the spin-momentum locking in topological insulators. Here we focus on how the detection of this inter-conversion can be made electrically, using three different cross-shaped nanostructures. We apply these measurement configurations to the case of the spin Hall effect in Pt, using CoFe electrodes to detect and inject spins. Both the direct and inverse spin Hall effect can be detected, with a spin Hall signal up to two order 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, comparison of the observed spin signals with finite element method calculations allows extracting the spin Hall angle and the spin diffusion length of Pt.