1. Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, School of Materials Science and Engineering and National Institute for Advanced Materials, Nankai University, Tianjin 300350, P. R. China
2. Henan Key Laboratory of Infrared Materials and Spectrum Measures and Applications, Henan Normal University, Xinxiang 453007, P. R. China