Abstract
The magnitude of spin-orbit torque (SOT), exerted to a ferromagnet (FM) from an adjacent heavy metal (HM), strongly depends on the amount of spin current absorbed in the FM. We exploit the large spin absorption at the Ru interface to manipulate the SOTs in HM/FM/Ru multilayers. While the FM thickness is smaller than its spin dephasing length of 1.2 nm, the top Ru layer largely boosts the absorption of spin currents into the FM layer and substantially enhances the strength of SOT acting on the FM. Spin-pumping experiments induced by ferromagnetic resonance support our conclusions that the observed increase in the SOT efficiency can be attributed to an enhancement of the spin-current absorption. A theoretical model that considers both reflected and transmitted mixing conductances at the two interfaces of FM is developed to explain the results.
| Original language | English (US) |
|---|---|
| Journal | Physical Review Letters |
| Volume | 117 |
| Issue number | 21 |
| DOIs | |
| State | Published - Nov 18 2016 |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledgements: This research is supported by the National Research Foundation (NRF), Prime Minister’s Office, Singapore, under its Competitive Research Programme (CRP Award No. NRFCRP12-2013-01). H. Y. is a member of the Singapore Spintronics Consortium (SG-SPIN). A. M. acknowledges support from King Abdullah University of Science and Technology (KAUST).