Enhancing the Spin-Orbit Torque Efficiency by the Insertion of a Sub-nanometer β-W Layer

Yaojin Li; Xi Zha; Yifan Zhao; Qi Lu; Boyan Li; Chunlei Li; Ziyao Zhou; Ming Liu

doi:10.1021/acsnano.2c00093

Enhancing the Spin-Orbit Torque Efficiency by the Insertion of a Sub-nanometer β-W Layer

ACS Nano. 2022 Aug 23;16(8):11852-11861. doi: 10.1021/acsnano.2c00093. Epub 2022 Jul 31.

Authors

Yaojin Li¹, Xi Zha¹, Yifan Zhao¹, Qi Lu¹, Boyan Li¹, Chunlei Li¹, Ziyao Zhou¹, Ming Liu¹

Affiliation

¹ Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronics and Information Engineering, the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an 710049, China.

PMID: 35912431
DOI: 10.1021/acsnano.2c00093

Abstract

Spin-orbit torque (SOT) efficiency is one of the key issues of spintronics. However, enhancing the SOT efficiency is usually limited by the positive correlation between resistivity and the spin Hall ratio, where a high resistivity often accompanies a large spin Hall ratio. Here, we demonstrate that sub-nanometer β-W intercalation has a considerable impact on the SOT efficiency in α-W (6 nm)/Co (8 nm)/Pt (3 nm) samples. The damping-like SOT efficiency per unit current density, ξ_DL^j, of α-W (5.7 nm)/β-W (0.3 nm)/Co (8 nm)/Pt (3 nm) shows a ∼ 296% enhancement compared to that of the α-W/Co/Pt system. Meanwhile, a resistivity similar to that of α-W and the spin Hall ratio larger than β-W induce a giant damping-like SOT efficiency per applied electric field, ξ_DL^E, which is about 12.1 times larger than that of β-W. Our findings will benefit the SOT devices by reducing energy consumption.

Keywords: interfacial spin transparency; resistivity; spin Hall ratio; spin−orbit torque efficiency; sub-nanometer intercalation.