1. Department of Physics, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thailand
2. Faculty of Biomedical Engineering, Czech Technical University in Prague, Nám. Sítná 3105, Kladno, Czech Republic
3. Institute of Physics, AS CR, Cukrovarnicka 10, Prague 16253, Czech Republic
4. Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
5. NICHe, Tohoku University 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan