Affiliation: | a Institute of Glasses and Ceramics, Academy of Mining and Metallurgy, Al. Mickiewicza 30, Kraków, Poland;b Institute of Physics, University WSP, Al. Armii Krajowej 13/15, 42201 Cz
stochowa, Poland;c Laboratoire de Physique Appliqué et d'Automatique, Universite de Perpignan 52, Avenue de Villeneve, 66860 Perpignan Cedex, France |