1. University of Bordeaux, LCPO, UMR 5629,
F-33600 Pessac, France
2. CNRS, LCPO, UMR 5629, F-33600 Pessac,
France
3. Institut National Polytechnique Félix Houphouet-Boigny, LAPISEN,
BP 1313 Yamoussoukro, Ivory Coast
4. Swiss Federal Laboratories for Materials Science and Technology (EMPA), CH-8600
Dübendorf, Switzerland