Harnessing orbital Hall effect in spin-orbit torque MRAM.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39747072.
- Also identified by DOI 10.1038/s41467-024-55437-x and PMC identifier 11696791.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Spin-Orbit Torque (SOT) Magnetic Random-Access Memory (MRAM) devices offer improved power efficiency, nonvolatility, and performance compared to static RAM, making them ideal, for instance, for cache memory applications. Efficient magnetization switching, long data retention, and high-density integration in SOT MRAM require ferromagnets (FM) with perpendicular magnetic anisotropy (PMA) combined with large torques enhanced by Orbital Hall Effect (OHE). We have engineered a PMA [Co/Ni]<sub>3</sub> FM on selected OHE layers (Ru, Nb, Cr) and investigated the potential of theoretically predicted larger orbital Hall conductivity (OHC) to quantify the torque and switching current in OHE/[Co/Ni]<sub>3</sub> stacks. Our results demonstrate a ~30% enhancement in damping-like torque efficiency with a positive sign for the Ru OHE layer compared to a pure Pt layer, accompanied by a ~20% reduction in switching current for Ru compared to pure Pt across more than 250 devices, leading to more than a 60% reduction in switching power. These findings validate the application of Ru in devices relevant to industrial contexts, supporting theoretical predictions regarding its superior OHC. This investigation highlights the potential of enhanced orbital torques to improve the performance of orbital-assisted SOT-MRAM, paving the way for next-generation memory technology.