1. School of Chemical and Material Science, Key Laboratory of Magnetic Molecules & Magnetic Information Materials, the Ministry of Education, Shanxi Normal University 1 , No. 339, Taiyu Road, Taiyuan, Shanxi 030031, People’s Republic of China
2. School of Geographical Sciences, Shanxi Normal University 2 , No. 339, Taiyu Road, Taiyuan, Shanxi 030031, People’s Republic of China