Dielectric properties and AC conductivity of rare earth ions doped borotellurite glasses

A set of zinc-molybdenum-boro-tellurite glasses doped with erbium nanoparticles with chemical composition, (B2O3)0.1-(TeO2)0.5-x-(MoO3)0.4-(Er2O3)x, x =0.01, 0.02, 0.03, 0.04 and 0.05 have been prepared by sudden quenching the melt to room temperature. Non-crystalline nature of the samples has been confirmed by powder XRD studies. After annealing the samples at an appropriate temperature, they have been investigated for dielectric properties in the frequency range from 50Hz to 15 MHz and temperature from 300K to 610K in a Precession Impedance Analyzer. Both dielectric constant and loss factor decreased with increase of frequency and increased with increase of temperature. These variations have been explained in terms of different contributions to the total polarizability. Conductivity has been estimated from dielectric data. By regressional analysis of the conductivity, its DC and AC components and frequency exponent of AC conductivity have been obtained. AC conductivity increased with temperature and frequency. Temperature variation of both DC and AC conductivity have been subjected to analysis using Mott’s small polaron hopping model and Activation energy for conduction has been obtained. It is for the first time boro tellurite glasses doped with rare-earth nano particles have been studied for dielectric and AC conductivity and analyzed data systematically in terms of composition, frequency and temperature.