Influence of titanium ions on spectroscopic and dielectric properties of PbO-Bi2O3-As2O3 glasses

Abstract

PbO-Bi2O3-As2O3 glasses mixed with different concentrations of TiO2 (ranging from 0 to 2.0 mol %) were prepared. The amorphous nature of the samples was confirmed by X-ray diffraction and scanning electron microscopy. Spectroscopic studies (viz., optical absorption, IR and ESR) and dielectric properties (viz., dielectric constant, dielectric loss and a.c. conductivity) of these samples have been studied. The optical absorption and ESR spectral studies point out that the titanium ions co-exist in Ti3+ state with Ti4+ state. The dielectric parameters viz., ε′, tan δ and σac are found to decrease and the activation energy for a.c. conduction is found to increase with the increase in the concentration of TiO2 beyond 0.8 mol %. The analysis of dielectric relaxation effects exhibited by these glasses indicated that there is a spreading of relaxation times. The conduction in the high-temperature region seems to be connected with both electronic and ionic. © 2009 IOP Publishing Ltd.