Direct electrical observation of spin Hall effect in Bi film

The strong spin-orbit coupling of Bi makes it an ideal candidate for investigation of the spin Hall effect. Here, we provide the report of a direct electronic observation of the spin Hall effect in Bi film. When a current flows in the Bi film, electrons with opposite spin orientations separately accumulate on the top and bottom surfaces due to the spin Hall effect. The accumulated spins are electrically detected by a ferromagnetic film attached to the bottom surface of the Bi film. At a temperature of 3.0K, the observed voltage difference induced by the magnetization reversal is 1.2μV. By using the previously reported calculation based on the semiclassical Boltzmann equation, we find that the spin Hall conductivity multiplied by the spin injection efficiency is 1.98×102(Ωm)−1.