Structural and electrical properties of lead free ceramic: Ba(La(1/2)Nb(1/2))O(3)

Abstract

Lead free perovskite Ba(La(1/2)Nb(1/2))O(3) was prepared by conventional ceramic fabrication technique at 1375 degrees C for 7 h in air atmosphere. The crystal symmetry, space group and unit cell dimensions were estimated using Rietveld analysis. X-ray diffraction analysis indicated the formation of a single phase monoclinic structure with space group P2/m. Energy dispersive X-ray analysis and scanning electron microscopy studies were carried to study the quality and purity of the compound. Permittivity data showed low temperature coefficient of capacitance (T(CC)=11%) up to 100 degrees C. The circuit model fittings were carried out using the impedance data to find the correlation between the response of real system and idealised model electrical circuit. Complex impedance analyses suggested the dielectric relaxation to be of non-Debye type. The correlated barrier hopping model was employed to successfully explain the mechanism of charge transport in Ba(La(1/2)Nb(1/2))O(3). The AC conductivity data were used to evaluate the density of states at Fermi level, minimum hopping length and apparent activation energy.