Spectroscopic and dielectric properties of crystallized PbO-Sb2O3-As2O3:NiO glass system

Glasses of the composition 40PbO-(20 - x)Sb2O3-40As2O3 were crystallized with different concentrations of NiO (x) ranging from 0 to 1.5 mol%. The samples were characterized by X-ray diffraction, scanning electron microscopy and differential thermal analysis techniques. The X-ray diffraction and the scanning electron microscopic studies have revealed the presence of NiSb2O6, NiAs2O4, Ni2As2O7, Pb5Sb2O8, PbSb2O6, Pb5Sb4O11 crystalline phases in these samples. Spectroscopic (IR and optical absorption), magnetic and dielectric studies have been investigated. The IR spectral studies have pointed out the glass ceramic network is composed of conventional AsO3 and SbO3 structural units; these studies have further indicated that the concentration of symmetrical vibrations of above structural groups decrease with increase in the concentration of NiO beyond 0.8 mol%. The analysis of the results of optical absorption, magnetic properties and dielectric properties has indicated that there is a gradual transformation of Ni2+ ions from octahedral to tetrahedral positions when the concentration of the crystallizing agent NiO is increased beyond 0.8 mol%. From these results it is also assessed that the glass crystallized with about 0.8 mol% of NiO is more suitable for getting maximum luminescence efficiency in the NIR region.