Complex Dielectric and Impedance Spectroscopic Studies in a Multiferroic Composite of Bi2Fe4O9-BiFeO3

Abstract Complex dielectric and impedance spectroscopic studies have been carried out in a detailed manner on the system comprising of Bi 2Fe 4O 9-BiFeO 3 composite particles dispersed in a α-Fe 2O 3 matrix as prepared using ball milling and controlled annealing treatments. This multiferroic composite is observed to exhibit a giant dielectric constant associated with a low tangent loss. A non-Debye type of relaxation has been deduced based on complex modulus analysis. Based on these studies, the important role played by bismuth ferrite nanoshell in the core-shell composite of Bi 2Fe 4O 9-BiFeO 3 is elucidated for the observed complex impedance spectroscopic properties of the system. Electron hopping across Fe 2+/Fe 3+ and oxygen vacancies are deduced to be playing an important role in conduction mechanisms based on activation energy analysis of the complex impedance spectroscopy results. View Full-Tex