1. Department of Physics, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
2. International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044, Japan
3. Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Japan
4. Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
5. Center for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan