Author(s):
1. Yiannis Tripanagnostopoulos, Physics Dept, University of Patras, Patra 26504, Greece
2. Eleni Karantagli, Dept of Materials Science, University of Patras, Patra 26504, Greece
3. Mihail Sigalas, Dept of Materials Science, University of Patras, Patra 26504, Greece

Abstract