1. Department of Physics and Texas Center for Superconductivity at University of Houston (TcSUH), Houston, Texas 77204, United States
2. Key Laboratory of Fluid and Power Machinery of Ministry of Education, School of Materials Science and Engineering, Xihua University, Chengdu 610039, China
3. SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
4. Materials Science and Engineering Program and Texas Center for Superconductivity at University of Houston (TcSUH), University of Houston, Houston, Texas 77204, United States