Structural, Microstructural and Electrical Properties of Lanthanum (La+3)-Modified Lead Iron Niobate Pb(Fe0.5Nb0.5)O3

Abstract

Lanthanum-modified Lead iron niobate ceramic oxides having chemical formula Pb(1-x)Lax(Fe0.5Nb0.5)(1-x/4)O3 (x=0.00, 0.02, 0.04, 0.06, 0.08) have been prepared using traditional solid state reaction route. Preliminary structural, microstructural and electrical studies were carried out by the powder x-ray diffraction, scanning electron microscopy and complex impedance spectroscopic technique in awide experimental conditions. The x-ray diffraction study confirmed the formation of perovskite structures of the newly modified ceramics. The lattice parameters were calculated using standard IUCR software CHECKCELL. Crystallite sizes of the samples were calculated from Williamson-Hall method. Microstructure/morphology of the materials was analyzed from SEM images. Dieletric and impedance spectroscopic studies of the materials were carried out as a function of temperature for a wide range of frequencies. The pure PFN ceramic oxide shows the phase transition from ferroelectric to paraelectric state around 1150C. There is a notable decrease in the transition temperature of La-PFN(x=0.02) ceramic and above 4% La concentration, the transition temperature falls below room temperature.