Giant spin Hall angle from topological insulator Bi$_{\mathrm{x}}$Se$_{\mathrm{(1-x)}}$ thin films

Investigation on the spin-orbit torque (SOT) from large spin-orbit coupling materials has been attracting interest because of its low power switching of the magnetization and ultra-fast driving of the domain wall motion that can be used in future spin based memory and logic devices. We investigated SOT from~topological insulator Bi$_{\mathrm{x}}$Se$_{\mathrm{(1-x)}}$~thin film in Bi$_{\mathrm{x}}$Se$_{\mathrm{(1-x)}}$~/CoFeB heterostructure by using the dc planar Hall method, where Bi$_{\mathrm{x}}$Se$_{\mathrm{(1-x)}}$~thin films were prepared by a unique industry-compatible deposition process.~The angle dependent Hall resistance was measured in the presence of a rotating external in-plane magnetic field at bipolar currents. The spin Hall angle (SHA) from this Bi$_{\mathrm{x}}$Se$_{\mathrm{(1-x)}}$~thin film was found to be as large as 22.41, which is the largest ever reported at room temperature (RT).~~The giant SHA and large spin Hall conductivity (SHC) make this Bi$_{\mathrm{x}}$Se$_{\mathrm{(1-x)}}$~thin film a very strong candidate as an SOT generator in SOT based memory and logic devices.