Enhancing Field-Like Efficiency Via Interface Engineering with Sub-Atomic Layer Ta Insertion

Abstract

The prevailing research emphasis has been on reducing the critical switching current density (J_c) by enhancing the damping-like efficiency (β_DL). However, recent studies have shown that the field-like efficiency (β_FL) can also play a major role in reducing J_c. In this study, the central inversion asymmetry of Pt-Co is significantly enhanced through interface engineering at the sub-atomic layer of Ta, thereby inducing substantial alterations in the β_FL associated with the interface. The β_FL has shown a 123% increase, from −1.66 Oe/(MA cm⁻²) to -3.8 Oe/(MA cm⁻²). As a result, the multilayered Ta/Pt/Ta (0.3 nm insertion)/Co/Ta structure leads to a notable decrease in J_c, exceeding a remarkable 90% compared to the simpler Ta/Pt/Co/Ta structure, ultimately achieving a significantly low value of 2.7 MA cm⁻². These findings pave the way for the development of highly efficient and energy-saving spin-orbit torque (SOT)-based spintronic devices, where further optimizations in interface engineering can unlock even greater potential in terms of reduced power consumption and enhanced performance.