1. Dipartimento di Fisica e Astronomia; Università di Bologna; Viale Berti Pichat 6/2 40127 Bologna Italy
2. i3N/CENIMAT; Department of Materials Science; Faculty of Science and Technology; Universidade NOVA de Lisboa and CEMOP/UNINOVA; Campus de Caparica; 2829-516 Caparica Portugal
3. CEA, LITEN; 17 rue des Martyrs F-38054 Grenoble France