Effect of Inserting a Transition Metal Cu Layer on the Spin‐Orbit Torque‐Induced Magnetization Switching in Pt/Co/Ta Structures

Current induced spin‐orbit torque (SOT) in perpendicularly magnetized heavy metal/ferromagnetic metal/heavy metal trilayers has been widely studied to achieve the current‐induced magnetization switching. Decreasing the critical switching current‐density (J_C) is a primary factor in the performance of memory or logic devices because J_C directly affects the power consumption of the devices. This work demonstrates the influences of inserting a transition metal copper (Cu) layer between the Co/Ta interface in the Pt/Co/Ta structures with perpendicular magnetic anisotropy (PMA) on the J_C, SOT, coercive field, and perpendicular magnetic anisotropy field (H_an). The results show that J_C decreases significantly when the thickness of Cu layer is above 3 nm, compared with the Pt/Co/Ta control sample, under consideration of the shunting effect of Cu layer. The decrease of J_C is the result of the competition between the modified SOT and H_an due to the insertion of Cu. The study suggests that the critical switching current‐density of SOT‐switching can be decreased by inserting a transition metal Cu layer.