Investigations on dielectric, electrical and ferroelectric properties of xBaTiO3-(1-x) NiFe2O4 multiferroic composite ceramics

This paper reports the synthesis of xBaTiO(3)-(1 - x)NiFe2O4 (where x = 0.8, 0.7, 0.6, 0.5) (BT-NF) ceramic composites by wet chemical route. Phase formation of the individual components and the BT-NF composite was studied using X-ray diffraction technique. Variation of dielectric constant and dielectric loss as a function of frequency (100 Hz to 1 MHz) and temperature (RT to 300 degrees C) were also investigated. Dielectric constant and dielectric loss were found to increase with an increase in ferrite content. Two peaks were observed in epsilon vs T curve, the peak in the lower temperature region 120 degrees C was attributed to ferroelectric to paraelectric transition and the second peak was due to the presence of ferrite phase in the composite. Conduction mechanism in the composites was studied with the help of Cole-Cole plots to understand the grain and grain boundary contribution to conductivity. P-E loops were measured at room temperature which demonstrates that all composite ceramics are ferroelectric and the increase in ferroelectricty in the ceramics was due to space charge and not an intrinsic phenomenon.