Physical and electrical properties of Sm₂O₃ doped Boro-Zinc-Vanadate glasses

Abstract

Sm2O3 doped boro-zinc-vanadate glass systems were synthesised by following the melt quenching method. XRD patterns indicated largely non-crystalline nature with few nano-crystallites. Room temperature density was measured. Molar volume and various polaron parameters were estimated. Density and molar volume are found to vary non-linearly with samarium concentration. Conductivity has been measured by two probe technique for temperature range 303K - 573K. High temperature conductivity obeyed the small polaron hopping (SPH) theory. Activation energy for conduction in the temperature regime of small polaron theory is found to vary from 0.249 eV to 0.368 eV non-linearly with Sm2O3 concentration. The conductivity data at low temperature deviated has been looked into using Mott’s VRH model and the density of states at Fermi level were determined. Shimakawa’s multiphonon tunnelling model has also been applied to the low temperature conductivity and found linearity between logarithmic conductivity, ln(σ) and logarithmic temperature ln(T) as predicted by the model. The temperature exponent values obtained from Shimakawa’s model fit are found to be in good agreement with literature. Therefore, it is concluded that at low temperature, carrier multiphonon tunnelling is the charge transport mechanism in the present glasses.