Effect of the low-resistance tunnel barriers induced inhomogeneous spin current distribution in graphene crossed configuration lateral spin valve
Yanping Liu,
Cheng Zeng,
Junnan Ding,
Jiahong Zhong,
Yuanji Gao,
Xiaofei Kuang,
Juan Yu,
Lingkai Cao,
Jun He,
Zongwen Liu
Affiliations
Yanping Liu
School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People’s Republic of China
Cheng Zeng
School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People’s Republic of China
Junnan Ding
School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People’s Republic of China
Jiahong Zhong
School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People’s Republic of China
Yuanji Gao
School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People’s Republic of China
Xiaofei Kuang
School of Electronics and Information, Hangzhou Dianzi University, 1158 Second Street, Xiasha College Park, Hangzhou, Zhejiang 310018, China
Juan Yu
School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People’s Republic of China
Lingkai Cao
School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People’s Republic of China
Jun He
School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People’s Republic of China
Zongwen Liu
School of Chemical and Biomolecular Engineering, The University of Sydney, NSW 2006, Australia
The nonlocal spin valve configuration consists of two ferromagnetic and nonmagnetic channels, which is an effective configuration for determining spin injection and accumulation. Here, we report that a reversed nonlocal spin signal was detected by changing the voltage probe configurations in graphene (Py/MgO/graphene/MgO/Py) lateral spin valves. The abnormal reversed spin-dependent nonlocal voltage is attributed to the nonuniform pinhole at the interface of the low-resistance tunnel barrier, which makes the charge current flow through the detection electrode and return to the graphene channel. We demonstrate that the channel-width induced spin-polarized current inhomogeneity significantly contributes to nonlocal resistance. A detailed description and simulated results of the tunnel junctions provide evidence for the reversal of the nonlocal voltage sign induced by the low-resistance tunnel barriers. Our work sheds light on the understanding of the spatial distribution of the spin current and the effect of the tunnel barrier, which are essential for the development of spintronic devices.