Enhancing the Spin-Orbit Torque Efficiency by the Insertion of a Sub-nanometer β-W Layer

Spin-orbit torque (SOT) efficiency is one of the key issues of spintronics. However, enhancing the SOT efficiency is usually limited by the positive correlation between resistivity and the spin Hall ratio, where a high resistivity often accompanies a large spin Hall ratio. Here, we demonstrate that sub-nanometer beta-W intercalation has a considerable impact on the SOT efficiency in alpha-W (6 nm)/Co (8 nm)/Pt (3 nm) samples. The damping-like SOT efficiency per unit current density, xi(j)(DL), of alpha-W (5.7 nm)/beta-W (0.3 nm)/Co (8 nm)/Pt (3 nm) shows a similar to 96% enhancement compared to that of the alpha-W/Co/Pt system. Meanwhile, a resistivity similar to that of alpha-W and the spin Hall ratio larger than beta-W induce a giant damping-like SOT efficiency per applied electric field, SDL E , which is about 12.1 times larger than that of beta-W. Our findings will benefit the SOT devices by reducing energy consumption.

Automated summary

This study demonstrates the significant impact of sub-nanometer beta-W intercalation on the spin-orbit torque (SOT) efficiency in alpha-W/Co/Pt samples. The enhancement of damping-like SOT efficiency and the reduction of energy consumption can be achieved by introducing beta-W intercalation.