Title: Enhancement of the spin–orbit torque efficiency in W/Cu/CoFeB heterostructures via interface engineering

Abstract

Here, the spin-torque ferromagnetic resonance signal and the spin Hall magnetoresistance induced by the spin Hall effect of W/Cu/CoFeB heterostructures with different Cu layer thicknesses (t_Cu) have been systemically studied. The effective spin mixing conductance $$g^{↑↓}_{eff}$$, the interfacial spin transparency T, and the real spin–orbit torque efficiency ${\left(\frac{J_{\mathrm{s}}}{J_{\mathrm{c}}}\right)}_{\mathrm{real}}$show a significant increase compared to the W/CoFeB heterostructure. ${\left(\frac{J_{\mathrm{s}}}{J_{\mathrm{c}}}\right)}_{\mathrm{real}}$reaches its maximum of ~0.54, increased up to ~50% at the optimized tCu ~ 0.52 nm according to our theoretical prediction. More importantly, the intrinsic spin Hall angle of W, $$θ^{int}_{SH}$$ ~ 0.79 ± 0.20, has also been obtained after the correction of the inverse spin Hall effect and T. This suggests that the Cu insertion improves the interface quality and, therefore, assists the spin transport in the heterostructures, which potentially improves the performance of next-generation spintronic devices.

Authors:

Yang, Pei ^[1]; Shao, Qiming  ^[2];

• Search DOE PAGES for author "Shao, Qiming"
• Search DOE PAGES for ORCID "0000-0003-2613-3031"

Yu, Guoqiang ^[3]; He, Congli ^[4]; Wong, Kin  ^[5];

• Search DOE PAGES for author "Wong, Kin"
• Search DOE PAGES for ORCID "0000-0001-6776-3852"

Lu, Xianyang  ^[6];

• Search DOE PAGES for author "Lu, Xianyang"
• Search DOE PAGES for ORCID "0000-0003-3815-4032"

Zhang, Junran  ^[6];

• Search DOE PAGES for author "Zhang, Junran"
• Search DOE PAGES for ORCID "0000-0002-4536-3812"

Liu, Bo ^[7]; Meng, Hao ^[7]; He, Liang  ^[6];

• Search DOE PAGES for author "He, Liang"
• Search DOE PAGES for ORCID "0000-0002-5279-0097"

Wang, Kang L. ^[5]; Xu, Yongbing ^[8]

---

+ Show Author Affiliations

1. Nanjing Univ. (China); Univ. of California, Los Angeles, CA (United States)
2. Univ. of California, Los Angeles, CA (United States);The Hong Kong University of Science and Technology (China)
3. Univ. of California, Los Angeles, CA (United States) ;Beijing Normal University (China)
4. Univ. of California, Los Angeles, CA (United States); Beijing Normal University (China)
5. Univ. of California, Los Angeles, CA (United States)
6. Nanjing Univ. (China)
7. Key Laboratory of Spintronics Materials, Devices and Systems of Zhejiang Province, Zhejiang Province, China (Asia)
8. Nanjing Univ. (China); Univ. of York (United Kingdom)

Publication Date:

Mon Aug 24 00:00:00 EDT 2020

Research Org.:

Univ. of California, Riverside, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1802452

Grant/Contract Number:  

SC0012670

Resource Type:

Accepted Manuscript

Journal Name:

Applied Physics Letters

Additional Journal Information:

Journal Volume: 117; Journal Issue: 8; Journal ID: ISSN 0003-6951

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Physics; Spin pumping; Spintronics; Spin Hall effect; Heterostructures; Spintronic devices; Ferromagnetic resonance