Structural and electrical properties of calcium substituted lanthanum ferrite powders

Pure and calcium substituted lanthanum ferrite compounds, La1 − xCaxFeO3 − δ (x = 0, 0.05, 0.1 and 0.2), were successfully synthesized using the polymerizable complex method. Several techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and complex impedance analysis (CIA) were used to characterize the obtained samples. Whatever the calcium concentration, all the compounds are identified as single perovskite phases. No significant morphological changes are noted upon lanthanum substitution. All the prepared powders are composed of fine and homogeneous particles with a crystallite size ranging from 32 nm (for LaFeO3) to 12 nm (for La0.8Ca0.2FeO3 − δ). A noticeable improvement of electrical conductivity is noted with increasing calcium amounts. In particular, it was found that La0.8Ca0.2FeO3 − δ conductivity is thirty times higher than that of the parent lanthanum ferrite oxide.