While spin-orbit torque magnetic random-access memory (SOT-MRAM) is rapidly approaching commercialization, the technology has hit a severe industrial roadblock. The industry standard relies on β-phase tungsten (β-W) write electrodes, which suffer from high electrical resistance and strict thickness limitations. For chip manufacturers, these physical constraints translate directly to poor device consistency, high power consumption, and a hard limit on how small the memory cells can be scaled.
Now, a research team led by Professor Weisheng Zhao from Beihang University, and collaborators from Truth Memory Corporation, Aix-Marseille University and Université Paris-Saclay, has demonstrated a breakthrough that bypasses these limitations by harnessing the hidden degree of freedom, the orbital angular momentum. Published in the journal Science Bulletin , their work details a highly efficient orbital torque-driven magnetic tunnel junction (MTJ) that pushes orbitronics out of theoretical physics and into industrial application.
The researchers found that a precisely tuned ruthenium-tungsten (Ru/W) bilayer write electrode could serve as a highly efficient charge-to-orbital-to-spin converter. Next, they demonstrated that this novel write electrode interacted seamlessly with core magnetic layers in MTJs, maintaining strong perpendicular magnetic anisotropy and tunneling magnetoresistance (TMR) even after high-temperature manufacturing processes. After fabricating these devices on an industrial 8-inch MRAM pilot line, they verified that the new architecture solved critical yield bottlenecks, demonstrating highly uniform resistance across the wafer. Finally, performance tests confirmed this design as a highly viable commercial candidate because it dramatically lowered writing voltage and enabled ultra-fast 28.7-picosecond switching, while unlocking a shared-electrode structure that can shrink device area by an impressive 45% for massive future power and density improvements.
The team says further studies are needed, but this report represents the first step toward moving orbitronics from theoretical physics into real-world chips. “In light of these results, it will be necessary to further investigate the integration of these devices into large-scale memory arrays, moving this technology toward practical applications and providing a brand-new technical route for next-generation universal magnetic memory,” says Zhao
Science Bulletin