Investigation of transport behavior in Ba doped BiFeO3

Bi1−xBaxFeO3 (x = 0.00–0.25) samples were prepared by conventional solid state reaction method. X-ray diffraction revealed the rhombohedrally distorted perovskite structure for undoped BiFeO3 with a phase transition from rhombohedral to pseudo cubic on Ba substitution. The leakage current density of 10% Ba substituted sample is found to be four orders of magnitude less than that of the pure BiFeO3. Grain boundary limited conduction and space charge limited conduction mechanisms are involved in low and high electric field regions respectively for all the samples except 10% Ba doped BFeO3 which obeys grain boundary limited conduction mechanism in whole of the electric field range. Dielectric measurements showed that the dielectric constant and dielectric loss attained their minimum values at 10% Ba substitution. Thus 10% Ba is found to be optimum concentration to have better multiferroic properties. Undoped BiFeO3 and 5% Ba doped samples have very large values of dielectric constants and leakage current densities which can be attributed to a large number of oxygen vacancies in these samples, indicating an extrinsic response of these compositions.