1. Department of Materials Science and Engineering, National University of Singapore, Singapore 117575
2. Data Storage Institute, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way #08-01 Innovis, Singapore 138634
3. Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore 117603
4. Department of Physics, National University of Singapore, Singapore 117542