1. School of Physics and Electronic Science, Shanxi Datong University, Datong 037009, Shanxi, P. R. China
2. Test Center, CITIC Dicastal Co., Ltd., Qinhuangdao 066004, Hebei, P. R. China
3. Key Lab of Metastable Materials Science & Technology and College of Materials Science & Engineering, Yanshan University, Qinhuangdao 066004, Hebei, P. R. China