Structural, microstructural and electrical properties of Lanthanum (La+3) modified Lead iron niobate Pb(Fe0.5Nb0.5)O3.

Abstract

One series of lanthanum-modified Lead iron niobate ceramic oxideshaving chemical formula Pb(1-x)Lax(Fe0.5Nb0.5)(1-x/4)O3 (x=0.00,0.02,0.04,0.06,0.08) ceramics were prepared by mixed oxide high temperature solid state reaction route. Preliminary structural, microstructural and electrical properties of the compounds were studied using XRD, SEM and complex impedance spectroscopic analysis. The formations of the compounds were confirmed by XRD analysis. From preliminary structural using the XRD data, the lattice parameters are calculated using standard IUCR software CHECKCELL.Williamson Hall method was used for finding the crystallite size in the samples.Microstructures/morphology of the materials was analyzed by scanning electron microscopy.Dielectric and impedance spectroscopic properties of the materials were studied in a wide frequency range at different temperatures. The temperature dependent dielectric constant showed the ferroelectric to praelectric phase transition around 1150C for Pb(Fe0.5 Nb0.5)O3. Then with increase in La concentration, there is a decrease in the transition temperature and above 4% La concentration, the transition temperature is below the room temperature.