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

Abstract

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 (JC) is a primary factor in the performance of memory or logic devices because JC 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 JC, SOT, coercive field, and perpendicular magnetic anisotropy field (Han). The results show that JC 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 JC is the result of the competition between the modified SOT and Han 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.