1. College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610068, China
2. Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
3. Department of Physics and Electronic Science, Aba Teachers University, Wenchuan 623002, China
4. School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen 518172, China