1. School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Fert Beijing Research Institute, Beihang University, Beijing 100191, China
2. School of Electronics and Information Engineering, Beihang University, Beijing 100191, China
3. Department of Physics, University of Idaho, Moscow, Arkansas 83844, USA
4. Beijing Microelectronics Technology Institute, Beijing 100076, China
5. Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730030, China
6. China Institute of Atomic Energy, Beijing 102488, China
7. University of Wisconsin-Madison, Madison, Wisconsin 53706, USA