US Patent 11875827 SOT reader using BiSb topological insulator

The present disclosure generally relate to spin-orbit torque (SOT) devices. The SOT devices each comprise a non-magnetic layer, a free layer disposed in contact with the non-magnetic layer, and a bismuth antimony (BiSb) layer disposed over the free layer. The non-magnetic layer has a thickness of about 0.5 nm to about 2 nm. The BiSb layer has a thickness of about 5 nm to about 10 nm. The BiSb layer and the free layer have collective thickness between about 5 nm to about 20 nm. By reducing the thickness of the non-magnetic layer and BiSb layer, a read gap of each SOT device is reduced while enabling large inverse spin Hall angles and high signal-to-noise ratios.