Cobalt ion as a structural probe in PbO-As2O3 glass ceramics

PbO-As2O3 glasses mixed with different concentrations of CoO (ranging from 0 to 1.0 mol%) were crystallized. The samples were characterized by X-ray diffraction, scanning electron microscopy, EDS and differential scanning calorimetric techniques. The X-ray diffraction studies have indicated the presence of Pb(As2O6), Pb-3(AsO4)(2), Co6As2O11, Co3O4 crystalline phases in these samples. Optical absorption, IR and photoluminescence studies of these samples have been carried out. The analysis of the results of these studies has indicated that the cobalt ions exist in Co2+ and Co3+ states in the glass matrix. The studies have further revealed that as the concentration of the COO is increased, there is a gradual transformation of cobalt ions from tetrahedral to octahedral positions. (C) 2009 Elsevier Ltd. All rights reserved.