1. State Key Laboratory for Physical Chemistry of Solid Surfaces Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 P. R. China
2. Forschungszentrum Jülich IEK‐9 52425 Jülich Germany
3. Xiamen Institute of Rare Earth Materials Chinese Academy of Sciences Xiamen 361021 P. R. China
4. National High Magnetic Field Laboratory 1800 E. Paul Dirac Drive Tallahassee FL 32310 USA
5. College of Energy Xiamen University Xiamen 361005 P. R. China