In-situ study of oxygen exposure effect on spin-orbit torque in Pt/Co bilayers in ultrahigh vacuum

Abstract

Oxygen incorporation has been reported to increase the current-induced spin-orbit torque in ferromagnetic heterostructures, but the underlying mechanism is still under active debate. Here, we report on an in-situ study of the oxygen exposure effect on spin-orbit torque in Pt/Co bilayers via controlled oxygen exposure, Co and Mg deposition, and electrical measurements in ultrahigh vacuum. We show that the oxygen exposure on Pt/Co indeed leads to an increase of spin-orbit torque, but the enhancement is not as large as those reported previously. Similar enhancement of spin-orbit torque is also observed after the deposition of an MgO capping layer. The results of ab initio calculations on the Rashba splitting of Pt/Co and Pt/Co/O suggest that the enhancement is due to enhanced Rashba-Edelstein effect by surface-adsorbed oxygen. Our findings shed some light on the varying roles of oxygen in modifying the spin torque efficiency reported previously.

arXiv comment25 pages, 6 figures

References in corpus (22)

• Spin torque switching with the giant spin Hall effect of tantalum
• Spin Hall effect
• New Perspectives for Rashba Spin-Orbit Coupling
• Magnetic switching by spin torque from the spin Hall effect
• Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems
• Tunable Rashba spin-orbit interaction at oxide interfaces
• Strong spin-orbit splitting on Bi surfaces
• Quantitative characterization of the spin orbit torque using harmonic Hall voltage measurements
• Ultrafast magnetization switching by spin-orbit torques
• Room temperature spin-orbit torque switching induced by a topological insulator
• Rashba effect in the graphene/Ni(111) system
• Spin-orbit torque engineering via oxygen manipulation
• Diffusive spin dynamics in ferromagnetic thin films with a Rashba interaction
• Fieldlike and antidamping spin-orbit torques in as-grown and annealed Ta/CoFeB/MgO layers
• Rashba Effect at Magnetic Metal Surfaces
• Spin-orbit torques in heavy metal/ferromagnet bilayers with varying strength of interfacial spin-orbit coupling
• Thermally activated switching of perpendicular magnet by spin-orbit spin torque
• Electric Field Tuning of the Rashba Effect in the Polar Perovskite Structures
• Interfacial spin-orbit torque without bulk spin-orbit coupling
• Electrical control over perpendicular magnetization switching driven by spin-orbit torques
• Unveiling the role of Co-O-Mg bond in magnetic anisotropy of Pt/Co/MgO using atomically controlled deposition and in-situ electrical measurement
• Dynamic Control of Local Field Emission Current from Carbon Nanowalls