Effect of vanadium doping on the electrical charge transport and dielectric relaxation properties of Sodium Bismuth Titanate perovskite

Abstract

In this work, we report the effect of vanadium doping on the conductivity and relaxation dynamics of the charge carriers in Sodium Bismuth Titanate perovskite material (Na0.5Bi0.5TiO3) prepared by a unique technique which is a combination of chemical and mechanical methods. The parent material was prepared using the citrate auto-ignition method and the mechanical alloying technique was used to incorporate V2O5 in the NBT structure. The X-ray diffraction analysis confirmed the formation of the rhombohedral phase of NBT perovskite with space group R3c in all the compositions. The microstructural analysis was done using Field Emission Scanning Electron Microscopy, Energy-dispersive X-ray spectra, and the elemental mapping of the samples. The conductivity mechanism was analyzed using the complex impedance method. The sample with 15% doping showed the highest conductivity with minimum activation energy. The activation energies for conduction, relaxation, and migration of charge carriers were found to be comparable with each other. The frequency-dependent dielectric data was analyzed using Havriliak–Negami (HN) formalism and suggested non-Debye type relaxation behaviour. The 15% dopped composition showed the highest dielectric strength. The scaling behaviour of impedance and modulus spectra confirmed the temperature-independent conduction and relaxation mechanisms.