Generation and Detection of Pure Spin Current in an H-Shaped Structure of a Single Metal

Distinct from all the existing methods for determining the spin Hall angle with bilayers, we have developed a new approach based on the mesoscopic H-shaped structure, which generates and detects pure spin current in a single metal. Using this approach we have unequivocally addressed the long-standing controversy of the magnitude of the spin Hall angle of gold. By exploiting the long spin diffusion length of Cu and the large spin-orbit coupling of Bi, we have realized a very large spin Hall effect in 10 nm Cu films delta doped with 0.15 nm of Bi. This new artificial material can generate a large spin-orbit torque to switch an adjacent Fe layer. We have thus demonstrated new artificial materials with a simultaneously large spin Hall angle and long spin diffusion length.