|
1
|
Hwee Wong GD, Xu Z, Gan W, Ang CCI, Law WC, Tang J, Zhang W, Wong PKJ, Yu X, Xu F, Wee ATS, Seet CS, Lew WS. Strain-Mediated Spin-Orbit Torque Enhancement in Pt/Co on Flexible Substrate. ACS NANO 2021; 15:8319-8327. [PMID: 33970603 DOI: 10.1021/acsnano.0c09404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Current-induced magnetization switching by spin-orbit torque generated in heavy metals offers an enticing realm for energy-efficient memory and logic devices. The spin Hall efficiency is a key parameter in describing the generation of spin current. Recent findings have reported enhancement of spin Hall efficiency by mechanical strain, but its origin remains elusive. Here, we demonstrate a 45% increase in spin Hall efficiency in the platinum/cobalt (Pt/Co) bilayer, of which 78% of the enhancement was preserved even after the strain was removed. Spin transparency and X-ray magnetic circular dichroism revealed that the enhancement was attributed to a bulk effect in the Pt layer. This was further confirmed by the linear relationship between the spin Hall efficiency and resistivity, which indicates an increase in skew-scattering. These findings shed light on the origin of enhancement and are promising in shaping future utilization of mechanical strain for energy-efficient devices.
Collapse
Affiliation(s)
- Grayson Dao Hwee Wong
- School of Physical & Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
- GLOBALFOUNDRIES Singapore Pte. Ltd., 60 Woodlands Industrial Park D Street 2, Singapore 738406
| | - Zhan Xu
- School of Physical & Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Weiliang Gan
- School of Physical & Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Calvin Ching Ian Ang
- School of Physical & Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Wai Cheung Law
- School of Physical & Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
- GLOBALFOUNDRIES Singapore Pte. Ltd., 60 Woodlands Industrial Park D Street 2, Singapore 738406
| | - Jiaxuan Tang
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Wen Zhang
- School of Microelectronics, Northwestern Polytechnical University, Xi'an 710072, China
| | - Ping Kwan Johnny Wong
- School of Microelectronics, Northwestern Polytechnical University, Xi'an 710072, China
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603
| | - Feng Xu
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Andrew T S Wee
- Department of Physics and Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546
| | - Chim Seng Seet
- GLOBALFOUNDRIES Singapore Pte. Ltd., 60 Woodlands Industrial Park D Street 2, Singapore 738406
| | - Wen Siang Lew
- School of Physical & Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| |
Collapse
|
|
2
|
A scalable molecule-based magnetic thin film for spin-thermoelectric energy conversion. Nat Commun 2021; 12:1057. [PMID: 33594084 PMCID: PMC7887260 DOI: 10.1038/s41467-021-21058-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 01/06/2021] [Indexed: 11/08/2022] Open
Abstract
Spin thermoelectrics, an emerging thermoelectric technology, offers energy harvesting from waste heat with potential advantages of scalability and energy conversion efficiency, thanks to orthogonal paths for heat and charge flow. However, magnetic insulators previously used for spin thermoelectrics pose challenges for scale-up due to high temperature processing and difficulty in large-area deposition. Here, we introduce a molecule-based magnetic film for spin thermoelectric applications because it entails versatile synthetic routes in addition to weak spin-lattice interaction and low thermal conductivity. Thin films of CrII[CrIII(CN)6], Prussian blue analogue, electrochemically deposited on Cr electrodes at room temperature show effective spin thermoelectricity. Moreover, the ferromagnetic resonance studies exhibit an extremely low Gilbert damping constant ~(2.4 ± 0.67) × 10-4, indicating low loss of heat-generated magnons. The demonstrated STE applications of a new class of magnet will pave the way for versatile recycling of ubiquitous waste heat.
Collapse
|