1. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, P. R. China
3. Institut Néel, CNRS and Université J. Fourier, BP 166, 25 Avenue des Martyrs, 38042 Grenoble, France
4. Division of Quantum and Physical Chemistry, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
5. Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 15, 76131 Karlsruhe, Germany