1. Nanomaterials Research Institute National Institute of Advanced Industrial Science and Technology (AIST) Tsukuba 305‐8565 Japan
2. Laboratoire de Physique des Solides Université Paris‐Sud CNRS‐UMR 8502 Orsay 91405 France
3. Division of Electron Crystallography and Spectroscopy Tohoku University Sendai 980‐8577 Japan
4. Department of Electrical Engineering National Tsing Hua University Hsinchu 30013 Taiwan
5. Meijo University Department of Materials Science and Engeering Nagoya 468‐8502 Japan