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 °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.