1. Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku, Toyohashi, Aichi 441-8580, Japan
2. Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
3. Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Hyogo 678-1297, Japan
4. Synchrotron Radiation Nanotechnology Center, University of Hyogo, 1-490-2 Kouto, Shingu, Tatsuno, Hyogo 679-5165, Japan