1. Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta, Nagoya 456-8587, Japan
2. Graduate School of Material Science, University of Hyogo, 3-2-1, Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
3. Novel Crystal Technology, Inc., Sayama 350-1328, Japan