1. State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
2. Neutron Scattering Division, Oak Ridge National Laboratory (ORNL), 1 Bethel Valley Rd, Oak Ridge, Tennessee 37831, United States
3. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P. R. China
4. CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, P. R. China
5. The Institute for Advanced Studies, Wuhan University, Wuhan 430074, P. R. China
6. Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4003, United States