1. Graduate School of Science, Hiroshima University, Higashihiroshima, Hiroshima 739-8526, Japan
2. Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198, Japan
3. Geodynamics Research Center, Ehime University, Matsuyama 790-8577, Japan
4. Electronics and Materials R&D Laboratories, Sumitomo Electric Industries, Itami, Hyogo 664-0016, Japan