Orbital-to-spin conversion for efficient current-induced magnetization switching in nonmagnet/CoPt bilayers
Phys. Rev. B 114, 084418 – Published 19 August, 2026
DOI: https://doi.org/10.1103/y5h8-7nbn
Abstract
The orbital Hall effect (OHE) has attracted intensive studies recently due to its potential for substantially enhancing spin-orbit torque (SOT) generation, which is essential for the SOT-induced magnetization switching in spintronic devices. In this work, we report highly efficient SOT-driven magnetization switching in nonmagnet (NM)/CoPt bilayers, enabled by a pronounced OHE in NM and substantial orbital-to-spin conversion within the CoPt ferromagnet. The critical current density for the magnetization switching in a Ti/CoPt device is reduced by an order of magnitude compared to that in a CoPt single layer. Correspondingly, SOT efficiency measurements reveal an enhancement by one order of magnitude in Ti/CoPt relative to CoPt alone. This enhancement is attributed to the large OHE in Ti rather than its negligible spin Hall effect. The orbital current generated in Ti is injected into CoPt and then converted into spin current via strong spin-orbit coupling in CoPt. Our findings pave the way for leveraging orbital current to further amplify the efficiency of magnetization switching in spintronic devices.
