Effect of some VA group modifiers on R_2O_3 (R = Sb, Bi)-ZnF_2-GeO_2 glasses doped with CuO by means of spectroscopic and dielectric investigations

摘要

Transparentglasses 40Sb_2O_3-20ZnF_2-(40-x)GeO_2:xCuO,and 40Bi_2O_3-20ZnF_2-(40-y)GeO_2:yCuO with x = 0, 0.6 and 0 ≤y ≤ 1 wt% were prepared by melt quenching technique and were characterized by XRD and differential thermal analysis. Spectroscopic studies like optical absorption, FT1R, Raman, EPR and dielectric parameters (such as ε', loss(tan δ), and σ_(ac)) were carried out to examine the modifier and dopant effect on zinc germanate glass network. Optical absorption and EPR data have revealed that the environment of Cu~(2+) ions is more ionic in bismuth series rather than antimony glasses. Reduced bismuth ions have been found in pure and at lower concentration of dopant in Bi_2O_3 mixed glasses, which are useful for 1R amplifications. FTIR and Raman spectra have indicated the conversion of GeC>4 to GeO_6 structural units by forming cross linking bonds like Bi-O-Ge, Ge-O-Cu, etc., and open the glass network with integration of Bi_2O_3 and CuO doping. It is also confirmed by decreasing T_g and E_g values. The temperature dependence of dielectric parameters at different frequencies was interpreted in terms of structural changes in the glass network.