1. Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, School of Life Sciences, Peking University, Beijing 100871, China
2. Beijing Key Laboratory for Magnetoelectric Materials and Devices, School of Materials Science and Engineering, Peking University, Beijing 100871, China
3. Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
4. Fifth Medical Center, Chinese PLA General Hospital, Beijing 100039, China
5. College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China