Enhanced Spin-Orbit Torque and Low Critical Current Density in PtRu/[CoNi]/Ru Multilayer for Spintronic Devices.

Using a heavy-metal (HM) alloy layer in spin-orbit torque (SOT)-based devices is an effective method for obtaining a high current-spin conversion efficiency θ. In this work, SOT-based spintronic devices with a PtRu-alloyed HM layer are studied by applying harmonic Hall measurements and magneto-optical Kerr effect microscopy to detect the θ and to observe the process of current-induced magnetization switching. Both the highest θ of 0.132 and the lowest critical current density () of 8 × 10 A/cm are realized in a device with = 20, which satisfies the high SOT efficiency and low energy consumption simultaneously. The interfacial Dzyaloshinskii-Moriya interaction can be overcome by increasing the in-plane assist field. Meanwhile, the minimum in-plane field required for current-induced complete switching can be reduced to ±60 Oe. Our study reveals that using the Pt-Ru alloyed HM layer is an effective route for SOT application with enhanced performance.