Benchmarking of spin-orbit torque switching efficiency in Pt alloys

We systematically survey on Pt$_{x}$Cu$_{1-x}$/Co/MgO magnetic heterostructure with perpendicular magnetic anisotropy and report a significant improvement on spin-orbit torque switching efficiency in Pt-Cu alloy system. The largest damping-like spin-orbit torque efficiency determined by hysteresis loop shift measurement is about 0.44 for Pt$_{0.57}$Cu$_{0.43}$, which is originated from the higher resistivity tuned by alloying. Moreover, from the results of current-induced switching measurements, a lower critical switching current density is achieved by proper alloying due to the simultaneous enhancement of spin-orbit torque efficiency and reduction of coercivity of the Co layer. Finally, the ability to lower power consumption and preserve good thermal stability using Pt$_{x}$Cu$_{1-x}$ alloy is demonstrated, which suggests that Pt$_{x}$Cu$_{1-x}$ is an attractive candidate for future SOT-MRAM applications.