1. Superconductivity and New Energy R&D Center, Key Laboratory of Advanced Technology of Materials (Ministry of Education), Southwest Jiaotong University, Chengdu, China
2. School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, China
3. School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, China
4. College of Materials Science and Engineering, Hunan University, Changsha 410082, China
5. School of Physics and Electronics, Hunan University, Changsha 410082, China