1. Institute of Physics
AS CR, Cukrovarnicka 10, 16253 Prague, Czech Republic
2. Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 Japan
3. New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
4. Institute
of Applied Physics ‘‘N.Carrara’’ (IFAC)
of CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Firenze), Italy