1. Physics Department, University of Trieste, Via Valerio 2, 34127 Trieste, Italy
2. Instituto de Ciencia de Materiales de Madrid - ICMM-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
3. Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14 Km 163.5, 34149 Trieste, Italy
4. Department of Earth Sciences, Department of Physics and Astronomy, TYC@UCL, London WC1E 6BT, United Kingdom
5. London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, United Kingdom
6. Dipartimento di Fisica Ettore Pancini, Università di Napoli Federico II, Monte S. Angelo, 80126 Napoli, Italy
7. IOM-CNR, Laboratorio TASC, AREA Science Park, S.S. 14 km 163.5, 34149 Trieste, Italy