1. Kanagawa Academy of Science and Technology, KAST Lab. in Tokyo Institute of Polytechnics, 1583 Iiyama, Atsugi, Kanagawa, Japan, Department of Superconductivity and Applied Chemistry, Faculty of Engineering, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan, Research Center for Advanced Science and Technology, University of Tokyo, Komaba, Meguroku, Tokyo 153, Japan