Colossal Orbital Current Induced by Gradient Oxidation for High‐Efficiency Magnetization Switching

Abstract

AbstractOrbital angular momentum flow can be used to develop a low‐dissipation electronic information device by manipulating the orbital current. However, efficiently generating and fully harnessing orbital currents is a formidable challenge. In this study, an approach is presented that induces a colossal orbital current by gradient oxidation in Pt/Ta to enhance spin‐orbit torque (SOT) and achieve high‐efficiency magnetization switching. The maximum efficiency of the SOT before and after the gradient oxidation of Ta is improved relative to that of Pt by ≈600 and 1200%, respectively. The large SOT originates from the colossal orbital current because of the orbital Rashba–Edelstein effect induced by the gradient oxidation of Ta. In addition, a large spin‐to‐charge conversion efficiency is observed in yttrium iron garnet/Pt/TaOx because of the inverse orbital Rashba–Edelstein effect. Harnessing the orbital current can help effectively minimize the critical current density of the current‐induced magnetization switching to 2.26–1.08 × 106 A cm−2, marking a 12‐fold reduction compared to that using Pt. This findings provide a new path for research on low‐dissipation spin‐orbit devices and improve the tunability of orbital current generation.