Impact of niobium-doping on the impedance aspects and electrical conductivity mechanisms of Ba_0.97La_0.02Ti_1−xNb_4x/5O₃ solid solution

We synthesized polycrystalline samples of Ba_0.97La_0.02Ti_1−xNb_4x/5O₃, denoted as BLTi_1 − xNb_4x/5, with varying doping levels (x = 0.00, 0.02, and 0.05) through the Molten-Salt process. Introducing niobium had a significant impact on the physical characteristics of the BLT polycrystalline ceramics. Analysis via X-ray diffraction (XRD) indicated the presence of a single phase across all doping concentrations. As the concentration of Nb increased, there was a noticeable decrease in the typical size of crystallites. Scanning electron microscopy (SEM) revealed the formation of non-uniform particles as conventional grain size decreased with doping. We then investigated dielectric properties concerning frequency and composition under zero bias potential. Dielectric dispersion observed was interpreted utilizing both the Koops phenomenological theory and the Maxwell-Wagner interfacial model. Overall, under zero bias potential, Nb doping significantly impacted the electrical conductivity of BLT polycrystalline materials.