1. School of Physical Science and Technology, Guangxi University, Nanning 530004, P. R. China
2. School of Chemical & Environmental Engineering, China University of Mining and Technology-Beijing, Beijing 100083, P. R. China
3. CAS Center for Excellence in Nanoscience, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, P. R. China
4. Instituto de Ciencia de los Materiales de Madrid, CSIC, E-28049 Cantoblanco-Madrid, Spain
5. INTEQUI (UNSL, CONICET) and Facultad de Química, Bioquímica y Farmacia, UNSL, Chacabuco y Pedernera, San Luis 5700, Argentina
6. Institut Laue Langevin, BP 156X, Grenoble F-38042, France
7. Guangxi Key Lab of Processing for Nonferrous Metals and Featured Materials and Key Lab of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education; School of Resources, Environments and Materials, Guangxi University, Nanning 530004, P. R. China