Electrical conductivity and transport mechanisms in Bi-, Cu-, and W-doped BFN ceramic: a theoretical approach

Abstract

The perovskite complex 0.985(BaFe_0.5Nb_0.5O₃)-0.015(BiCu_0.75W_0.25O₃) (0.985BFN-0.015BCW) was successfully prepared using the solid-state reaction technique. The X-ray diffraction patterns reveal that the prepared sample crystallizes in cubic symmetry. Our paper provides an insight into the electrical transport behavior of our compound. Indeed, different conduction models are applied to interpret the electrical conductivity response. It was observed that the transport properties are influenced by hopping mechanisms across different temperature ranges, which explains both the changes in DC conductivity and the movement of charge carriers with temperature variations. This confirms that the charge carriers undergo thermal activation. The variation of the exponent s as a function of temperature indicates the presence of Quantum Mechanical Tunneling (QMT), Correlated Barrier Hopping (CBH), Non-overlapping Small Polaron Tunneling (NSPT), and Overlapping Large Polaron Tunneling (OLPT) in the transport properties. At the temperature range [160–540 K], the AC conductivity is found to obey “double Jonscher power law.” Besides, the frequency dependence of the conductivity obeys “single Jonscher power law” at higher temperatures. Additionally, the conductivity spectrum shows a high-frequency plateau, which suggests percolation behavior.