Affiliation: | a IFW Dresden, D-01069 Dresden, Germany b Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow Distr. 142432, Russia c Institute of Solid State Physics, TU Dresden, D-01069 Dresden, Germany d TASC-INFM Laboratory, Area Science Park - Basovizza, I-34012 Trieste, Italy e Dipartimento di Ingegneria dei Materiali ed Amb., Università di Modena e Reggio Emilia, Italy |