IR and ESR studies of CuO substituted for PbO in eutectic lead vanadate glass system

IR and ESR studies of CuO substituted for PbO in eutectic lead vanadate glasses of compositions x(CuO)(50 − x)PbO:50V2O5 with x = 0–15 mol%, prepared by melt quenching technique have been presented. It has been shown from X-ray diffraction that these samples are of amorphous nature. According to differential thermal analysis (DTA) studies, up to 10 mol% CuO substitution, the eutectic composition is maintained and it deviates for x = 15 mol% substitution. The structure of these glasses, investigated by means of IR studies show the presence of (VO3)n single chains and VO5 trigonal bipyramids. IR studies indicate that CuO is replacing PbO in the glass system. ESR spectra of CuO substituted samples are characterized by broad peaks probably because of the formation of Cu2+–V4+ exchange pairs. For devitrified CuO substituted samples the ESR spectra show exchange broadened but distinct features corresponding to V4+ and Cu2+entities. The ESR spectral features corresponding to Cu2+ indicate a d3z2-r2d3z2-r2 ground state, which indicates that Cu2+ probably has a tetragonally compressed co-ordination in lead metavanadate.