Investigation of electrical, magneto-dielectric and transport properties of multiferroic (1 − x) BiFeO3–(x) BaSr0.7Ti0.3O3 solid solutions

To date, many efforts are underway on single-phase multiferroic material to obtain a compound with strong magneto-dielectric coupling, improved dielectric properties and insulation behavior for their practical applications. In this work, high-quality powders of the (1 − x)BiFeO3(BFO)–(x)Ba0.7Sr0.3TiO3(BST) solid solutions were obtained by simple sol–gel assisted route. A detailed study on the interplay between the dielectric, magneto-dielectric and transport properties in ceramic samples is presented. Dielectric analysis reveals anomalies in the proximity of Neel temperature, indicating small magneto-electric coupling, which was confirmed through capacitance versus magnetic field measurements. Analysis of dc electrical response indicates no signature of Poole Frenkel (PF) and Schottky emission (SE) mechanism, but a dominating space charge-limited conduction (SLCS) mechanism was found in the studied samples. It is demonstrated a significant decrease of the current density with the increase of the BST concentration, suppressing the oxygen vacancies presence leading to an oxidation states stabilization of the Fe ions with doping. The results of the ac conductivity analysis suggest a small-polarons hopping mechanism at low-temperature region followed by ionized oxygen vacancies transport in the high-temperature region.