Ru/IrMn Interfacial Orbital-to-Spin Conversion for Antiferromagnetic Switching in Magnetic Tunnel Junctions

Current-induced antiferromagnetic (AFM) switching is critical for advancing spintronic technologies and expanding their functional landscape. Recently, the orbital Hall effect (OHE) has emerged as a promising mechanism for efficient control of AFM orders, though experimental validation has remained elusive. In this work, we successfully demonstrate efficient orbital-to-spin conversion in Ru/IrMn heterostructure, which enables significant enhancement of both OHE-induced damping-like and field-like torque efficiencies of 0.86 × 10⁵ Ω^-1m^-1 and 3.01 × 10⁵ Ω^-1m^-1, respectively. We further investigate the underlying orbital and spin diffusion behavior, revealing a rapid and efficient interfacial conversion mechanism. Additionally, we achieve complete, field-free OHE-induced AFM switching in 80 nm Ru/IrMn-based exchange-bias magnetic tunnel junctions (EB-MTJs), with an ultrafast 0.2 ns write speed and low energy consumption. These results establish a viable route for orbitronic manipulation of AFMs and offer a promising approach for ultrafast, low-power, and scalable spintronic devices.