1. Research & Development Department, Koito Manufacturing Co., 500, Kitawaki, Shimizu-ku, Shizuoka 424-8764, Japan
2. Department of Applied Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
3. Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259-S2-13, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan