1. Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education, College of Electrical Engineering, Southwest Jiaotong University, Chengdu, China
2. Key Laboratory of Advanced Technology of Materials, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, China
3. Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, China
4. Analysis and Testing Center, Southwest Jiaotong University, Chengdu, China
5. College of Physics and Energy, Fujian Normal University, Fuzhou, China