Enhanced dielectric properties of prospective Bi0.85Gd0.15Fe1−xCrxO3 multiferroics

Abstract

Scientific endeavor for tailoring properties of functional materials offers a significant urge to material scientists. The driving force is to facilitate the current understanding that may create new pathway to alternative materials. BiFeO3 is inherently multiferroic and its exploitation for applications in diversified fields are still required extensive investigations in different perspectives. In this context, we synthesized new Bi0.85Gd0.15Fe1−xCrxO3 multiferroics prepared by wet chemical method using high purity metal salts. We mainly focused on the investigation of dielectric properties, ac electrical conductivity and complex electrical modulus of the synthesized materials. Crystallographic measurements confirmed its rhombohedral structure which gradually transforms towards orthorhombic structure with increasing Cr dopants. The grain size of the synthesized samples was found to vary from 68 to 22 nm depending on doping concentration. Dielectric properties of sintered samples were studied in the frequency range of 100 Hz–1 MHz. Frequency dependent dielectric constant has shown to display dielectric dispersion behavior. At higher frequencies (⩾105 Hz), due only to electronic and ionic polarizations the dielectric constant has shown to be independent of frequency. Complex impedance showed a semicircular arc due to the dominant grain boundary resistance and the electric modulus confirms the existence of electrical relaxation. The AC conductivity (σAC) has shown to obey a power law. Obtained improved properties suggested that the synthesized Bi0.85Gd0.15Fe1−xCrxO3 ceramic by partial substitution of A and B sites by Gd3+ and Cr3+ shows added advantage in application over the pure BiFeO3 counterpart. Keywords: Functional ceramic, Dielectric, GB resistance, Polaron hopping, Annealing, Nanoparticles