1. a Angewandte Physik , University of Duisburg-Essen , D-47048 , Duisburg , Germany
2. b Institute of Physics , University of Silesia , PL-40-007 , Katowice , Poland
3. c Institute of Electronic Materials Technology , Pl-01-919 , Warsaw , Poland
4. d Department of Ceramic and Glass Engineering , University of Aveiro , 3810-193 , Aveiro , Portugal