[Ju, Sailong; Dai, Jiayu; Zhang, Enrui; Wu, Hongjian; Lai, Kang; Yang, Ming] Natl Univ Def Technol, Dept Phys, Changsha 410073, Peoples R China.
[Zhu, Hongen; Cui, Shengtao] Univ Sci & Technol China, Natl Synchrotron Radiat Lab, Hefei 230029, Peoples R China.
[Wang, Hanwen] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China.
[Yang, Bingjie; Li, Fangsen] Univ Sci & Technol China, Sch Nanotech & Nanobion, Hefei 230026, Peoples R China.
[Deng, Xiaohui] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.