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

Abstract Multi-component glasses of the chemical composition 19.5Li 2 O–20PbO–20B 2 O 3 –30SiO–(10 −  x )Bi 2 O 3 –0.5MnO: x Ga 2 O 3 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 Mn 3+ state in addition to Mn 2+ state in the samples containing low concentration of Ga 2 O 3 . The IR and Raman studies indicated increasing degree of disorder in the glass network with the concentration of Ga 2 O 3 up to 3.0 mol%. The dielectric constant, loss and ac conductivity are observed to increase with the concentration of Ga 2 O 3 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 Ga 2 O 3 is raised beyond 3.0 mol%. This has been attributed to adaption of gallium ions from octahedral to tetrahedral coordination.