Influence of Ga3+ ions on spectroscopic and dielectric features of multi component lithium lead boro bismuth silicate glasses doped with manganese ions

Multi-component glasses of the chemical composition 19.5Li2O–20PbO–20B2O3–30SiO–(10 − x)Bi2O3–0.5MnO:xGa2O3 with 0 ≤ x ≤ 5.0 have been synthesized. Spectroscopic (optical absorption, IR, Raman and ESR) and dielectric properties were investigated. Optical absorption and ESR spectral studies have indicated that managanese ions do exist in Mn3+ state in addition to Mn2+ state in the samples containing low concentration of Ga2O3. The IR and Raman studies indicated increasing degree of disorder in the glass network with the concentration of Ga2O3 up to 3.0 mol%. The dielectric constant, loss and ac conductivity are observed to increase with the concentration of Ga2O3 up to 3.0 mol%. The quantitative analysis of the results of dielectric properties has indicated an increase in the insulating strength of the glasses as the concentration of Ga2O3 is raised beyond 3.0 mol%. This has been attributed to adaption of gallium ions from octahedral to tetrahedral coordination.