Impedance spectroscopy and conductivity analysis of multiferroic BFO-BT solid solutions

We report the investigations on the impedance and conductivity analysis of BiFeO3-BaTiO3 (BFO-BT) system prepared by solid state reaction route. The impedance studies reveal the presence of grain and grain boundary effects as confirmed from the single and double arc in the complex Cole-Cole plots. The impedance measurements confirm the temperature dependent electrical relaxation processes in the material for all compositions of BFO-BT attributing to the presence of immobile species at low temperature and defects/vacancies at higher temperatures. The BFO-BT systems exhibit non-Debye type of electric relaxation with concentration x = 0.10, 0.15 and 0.30. The thermal variation of impedance parameters reflects a negative temperature coefficient of resistance behavior of the material analogous to semiconductor. The electrical conductivity studies obtained the activation energies related to grain contribution as 1.108, 0.795, 0.164 eV for (1 - x)BFO-xBT (x = 0.10, 0.15 and 030) and grain boundary as 0.708, 0.453 eV for (1 - x)BFO-xBT (x = 0.15 and 0.30) which is related to various factors including oxygen vacancies, mobility of defects, conduction via hopping and presence of same species responsible for conducting nature via grain and grain boundary. (C) 2016 Elsevier B.V. All rights reserved.