1. Institute
of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226−8503, Japan
2. Materials
Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226−8503, Japan
3. High Energy Accelerator
Research Organization, KEK, 1-1, Oho, Tsukuba, Ibaraki 305−0801, Japan
4. Department
of Materials Structure Science, School of High Energy Accelerator
Science, SOKENDAI, The Graduate University for Advanced Studies, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
5. ACCEL, Japan Science
and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
6. Laboratory
for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226−8503, Japan