1. York-Nanjing Joint Center (YNJC) for Spintronics and Nano-engineering, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
2. Spintronics and Nanodevice Laboratory, Department of Electronic Engineering, University of York, YO10 5DD, United Kingdom
3. Zhejiang Hikstor Technology Company, Hangzhou 311305, China
4. Department of Electronics, Royal Holloway University of London, TW20 0EX, United Kingdom
5. Department of Physics, University of York, York YO10 5DD, United Kingdom
6. NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, 7500 AEEnschede, The Netherlands
7. Institute of Physics, Chinese Academy of Science, Beijing 100190, China
8. National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China