1. Fert Beijing Institute, BDBC, School of Electronic and Information Engineering, Beihang University, Beijing 100191, China
2. Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266101, China
3. School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen 518172, China