1. National Institute for Materials Science
(NIMS), Namiki 1-1, Tsukuba 305-0044, Japan
2. Faculty of Pure and Applied Sciences, University of
Tsukuba, Tennodai 1-1, Tsukuba 305-8573, Japan
3. Department of Electrical Materials and Engineering,
University of Hyogo, Shosya 2167, Himeji, Hyogo 671-2280,
Japan
4. Graduate School of Arts and Sciences, University of
Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan