1. Department of Physics, Tokyo Medical College, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo 160
2. Laboratory of Physics, College of Science and Technology, Nihon University, 7-24-1 Narashinodai, Funabashi 274
3. The Institute for Solid State Physics, The University of Tokyo, 7-22-1, Roppongi, Minato-ku, Tokyo 106
4. Musashi Institute of Technology, 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo 158