1. Department of Materials Science and Engineering, Tokyo Institute of Technology, Yokohama 226-8502, Japan
2. Research Center for Functional Materials, National Institute for Materials Science (NIMS) Tsukuba 305-0044, Japan
3. Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, Yokohama 226-8502, Japan
4. Department of Materials and Life Sciences, Sophia University, Tokyo 102-8554, Japan
5. Department of Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
6. Department of Physics and Electronics, Osaka Prefecture University, Osaka 599-8531, Japan