1. Department of Physics, Faculty of Science, Chiba University, Yayoi-cho, Chiba 260
2. Department of Material Physics, Faculty of Engineering Science, Osaka University, Toyonaka 560
3. College of Liberal Arts, Kobe University, Nada-ku, Kobe 657
4. Institute for Solid State Physics, University of Tokyo, Roppongi, Minato-ku, Tokyo 106
5. Department of Physics, Faculty of Science, Saitama University, Urawa 338