Deterministic magnetization switching by giant orbital torque in perpendicularly magnetized V/Pt/Co heterostructures

Abstract

Spin–Orbit Torque Magnetic Random-Access Memory is a next-generation memory technology. Its conventional switching scheme relies on the spin Hall effect to switch the magnetization of the free layer. However, this approach depends mostly on the materials with strong spin–orbit coupling (SOC). In contrast, the orbital Hall effect offers an alternative pathway that can be efficiently generated even in light materials with weak SOC, e.g., Zr, Nb, and Cr, thereby expanding the range of materials available for energy-efficient magnetization switching. By integrating perpendicularly magnetized Co with the transition metal vanadium (V) in V/Pt/Co heterostructures, this study experimentally discovers a giant orbital Hall angle of 0.71 in V, reducing the critical switching current density (Jc) to 15.5 MA/cm2, a 78.5% decrease compared to conventional Pt-based systems. More importantly, the heterostructure maintains a relatively large coercivity (Hc) of 126 Oe, which indicates a high magnetic anisotropy (Ku) and therefore leads to a high thermal stability factor (Δ). The combination of high orbital torque efficiency, low Jc, and exceptional thermal stability establishes a new material platform for reliable, energy-efficient orbitronic memory applications.