[Xiao, Qin; Huang, Chuqiang; Zhang, Wei; Yu, Ying; Yu, Luo; Shuai, Ling; Qiu, Ming] Cent China Normal Univ, Coll Phys Sci & Technol, Inst Nanosci & Nanotechnol, Wuhan 430079, Peoples R China.
[Yu, Luo; Ren, Zhifeng] Univ Houston, Dept Phys, Houston, TX 77204 USA.
[Yu, Luo; Ren, Zhifeng] Univ Houston, Texas Ctr Superconduct, Univ Houston TcSUH, Houston, TX 77204 USA.
[Zhang, Jing; An, Pengfei] Chinese Acad Sci, Inst High Energy Phys, Beijing Synchrotron Radiat Facil, Beijing 100049, Peoples R China.