1. National Engineering Research Center for Rare Earth Materials, General Research Institute for Non-ferrous Metals and Grirem Advanced Materials Co. Ltd., Beijing 100088, China
2. College of Electronic Science and Engineering, Jilin University, Changchun 130000, China
3. China Electronic Product Reliability and Environmental Testing Research Institute, Guangzhou 510610, China
4. College of Physics, Jilin University, Changchun 130000, China