1. Hubei Key Laboratory of Ferro & Piezoelectric Materials and Devices, Faculty of Physics and Electronic Science, Hubei University, Wuhan 430062, P. R. China
2. Anhui High Reliability Chips Engineering Laboratory, Hefei Innovation Research Institute, Beihang University, Hefei, Anhui 230012, P. R. China
3. Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, P. R. China
4. National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
5. Key Laboratory of Geospace Environment, University of Science & Technology of China, Chinese Academy of Sciences, Hefei 230026, P. R. China
6. Research Institute of Interdisciplinary Science & School of Materials Science and Engineering, Dongguan University of Technology, Dongguan 523808, China