1. Institute for Materials Research, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai, Miyagi 980-8577, Japan
2. New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramaki-aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan
3. C&A Corporation, 1-15-9 Ichibancho, Aoba-ku, Sendai, Miyagi 980-0811, Japan
4. Institute of Physics, Czech Academy of Science, Cukrovarnická 10, 162 00 Prague, Czech Republic