A conductive topological insulator with large spin Hall effect for ultralow power spin-orbit torque switching

Spin-orbit torque switching using the spin Hall effect in heavy metals and topological insulators has a great potential for ultralow power magnetoresistive random-access memory. To be competitive with conventional spin-transfer torque switching, a pure spin current source with a large spin Hall angle (theta(SH) > 1) and high electrical conductivity (sigma > 10(5) Omega(-1) m(-1)) is required. Here we demonstrate such a pure spin current source: conductive topological insulator BiSb thin films with sigma approximate to 2.5 x 10(5) Omega(-1) m(-1), theta(SH) approximate to 52 and spin Hall conductivity sigma(SH approximate to) 1.3 x 10(7) h/2e Omega(-1) m(-1) at room temperature. We show that BiSb thin films can generate a very large spin-orbit field of 2.3 kOe MA(-1) cm(2) and a critical switching current density as low as 1.5 MA cm(-2) in Bi0.9Sb0.1/MnGa bilayers, which underlines the potential of BiSb for industrial applications.