1. IMRAM, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, Miyagi, 980-0812, Japan
2. Furukawa Co., Ltd., 1-25-13, Kannondai, Tsukuba, Ibaraki, 305-0856, Japan
3. Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via Cozzi 53, 20125 Milano, Italy
4. NICHe, Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan