[1] CNR, Ist Struttura Mat, I-00133 Rome, Italy
[2] European Synchrotron Radiat Facil, F-38000 Grenoble, France
[3] Technol Educ Inst TEI Crete, Ctr Mat Technol & Photon, Iraklion 71004, Crete, Greece
[4] TEI Crete, Dept Elect Engn, Iraklion 71004, Crete, Greece
[5] Fdn Res & Technol Hellas FORTH, IESL, Iraklion 71110, Crete, Greece
[6] Univ Crete, Dept Mat Sci & Technol, Iraklion, Greece