1. Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education
2. School of Physical Science and Technology
3. Lanzhou University
4. Lanzhou 730000
5. P. R. China
6. College of Mathematics and Physics
7. Qingdao University of Science and Technology
8. Qingdao
9. Department of Materials Science and Engineering
10. University of Washington
11. Seattle
12. USA