1. Department of Physics and Astronomy University of Nebraska Lincoln NE 68588 USA
2. Department of Materials Science and Engineering Norwegian University of Science and Technology (NTNU) Trondheim 7491 Norway
3. Department of Materials Science and Engineering Pennsylvania State University University Park PA 16802 USA
4. Centre for Nanostructured Media School of Mathematics and Physics Queen's University Belfast BT7 1NN UK
5. Institute of Geology and Mineralogy Section Crystallography University of Cologne Zulpicher Str. 49b Cologne 50674 Germany
6. Laboratory of Condensed Matter Physics University of Picardie Amiens 80039 France
7. Materials Science Division Argonne National Laboratory 9700 S Cass Ave Lemont IL 60439 USA
8. Department of Physics Norwegian University of Science and Technology (NTNU) Trondheim 7491 Norway