1. Faculty of Materials Science and Engineering
2. Kunming University of Science and Technology
3. Kunming 650093
4. China
5. Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons
6. Peter Grünberg Institute
7. Forschungszentrum Jülich
8. 52425 Jülich
9. Germany
10. Department of Materials Science and Engineering
11. School of Materials Science and Engineering
12. Beihang University
13. Beijing 100191