Tuning the High‐Efficiency Field‐Free Current‐Induced Deterministic Switching via Ultrathin PtMo Layer with Mo Content

Spin‐orbit torque (SOT)‐based magnetization switching is a promising candidate for the innovation and developments of spintronic devices. However, the necessity of an in‐plane magnetic field to induce deterministic switching is an obstacle to feasibility in practical applications. Here, it is shown that the field‐free current‐induced magnetization switching in a perpendicular magnetized Pt1−xMox/Co/Ru heterostructure with x = 0, 0.04, 0.07, 0.12, and 0.17. Applying an in‐plane charge current through the Pt1−xMox layer, the device can achieve a high‐efficiency field‐free current‐induced magnetization switching with competing spin currents generated from a single Pt1−xMox alloy layer due to opposite spin Hall angles (θSHA) of Pt and Mo atoms and locally induced electric field. Remarkably, the large θSHA of about 0.35 is achieved in the optimal composition of Pt0.88Mo0.12 alloy, which is much higher than that of the pure Pt structure. The results pave the way to resolve the future problems of scalability and thermal stability for SOT‐driven magnetic tunnelling junctions. High‐efficiency field‐free current‐induced magnetization switching in Ta/Pt1−xMox/Co/Ru heterostructure with ultrathin 2 nm thick of Pt1−xMox with x = 0, 0.04, 0.07, 0.12, and 0.17 is well maintained. The lateral symmetry is broken via competing spin currents and locally induced electric fields at the PtMo interface regime. Importantly, the large θSHAof about 0.35 is obtained in the optimal composition of Pt0.88Mo0.12.