1. Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
2. Fert Beijing Institute, BDBC, School of Microelectronics, Beihang University, Beijing 100191, China
3. Department of Physics, University of Idaho, Moscow, Idaho 83844-0903, USA
4. School of Electronic and Information Engineering, Beihang University, Beijing 100191, China
5. Goertek Inc., Weifang 261031, China