1. Research Center for Electronic and Optical Materials, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
2. Center for Basic Research on Materials, NIMS, 1-1 Namiki, Tsukuba 305-0044, Japan
3. Murata Manufacturing Co., Ltd., 1-10-1 Higashikotari, Nagaokakyo-shi, Kyoto 617-8555, Japan