1. Key Lab of Advanced Transducers and Intelligent Control System of Ministry of Education, and Department of Physics and OptoelectronicsTaiyuan University of Technology Taiyuan 030024 P. R. China
2. State Key laboratory of Advanced Design and Manufacturing for Vehicle BodyCollege of Mechanical and Vehicle EngineeringHunan University Changsha 410082 P. R. China
3. Wuhan National High Magnetic Field CenterHuazhong University of Science and Technology Wuhan 430074 P. R. China