Effect of antimony substitution on structural and electrical properties of LaFeO3

Fine crystalline LaFeO3 and antimony-substituted compounds have been prepared by co-precipitation method. The as synthesized materials have been sintered at 1000 degrees C for single-phase compound formation and evaluated for their electrical and structural properties. TG/DTA studies ascribed that the precursor powders have undergone rapid changes during the transformation of LaFeO3 and substituted compounds. XRD data reveal the presence of well-defined sharp peaks, indicating the single-phase perovskite structure of LaFeO3 and polycrystalline structure of LaFeO3 and Sb2O3 compounds. The FT-IR spectra exhibit an absorption band corresponding to Fe-O stretching vibration, which is shifted on the substitution of Sb3+, ions. The temperature dependent d.c. conductivity shows the semiconducting behavior of the synthesized materials. The band gap values are found to increase upto x = 0.4 and decrease on further increase in concentrations of the Sb3+ ions. The decrease in dielectric constant with increasing frequency explained the Maxwell-Wagner interfacial polarization model. (C) 2008 Published by Elsevier B.V.