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La1-xSrxMn0.50Fe0.50O3 {0.10 ≤ x ≤ 0.40} perovskite ceramics material is prepared by solid-state reaction method and samples are characterized to study their structural, thermal, electrical and dielectric properties. X-ray diffraction results show that as prepared samples are well crystallized in single phase and have rhombohedral crystal structure. Density is measured by Archimedes principle and with Sr substitution its value decreasing. Thermogravimetric analysis shows the weight gain in the material above 300 ºC. Thermal expansion coefficient value for x = 0.10 and 0.40 composition is found to be 12.9 × 10-6 ºC−1 and 11.3 × 10-6 ºC−1, respectively upto 800 ºC. Impedance analyzer is used to study dielectric and electrical properties which show that all the as prepared samples obey non-Debye relaxation behaviour. The maximum conductivity value is 121.09 S cm-1 for x = 0.10 and 155.96 S cm-1 for x = 0.40 at 600 ºC and 303.59 S cm-1 for x = 0.10 and 362.35 S cm-1 for x = 0.40 at 800 ºC which confirmed that in the experimental perovskite the conductivity increases after Sr doping. Activation energy also found to be decreases with Sr substitution. Therefore, studied properties confirmed that the as-prepared material is a suitable cathode material for intermediate temperature solid oxide fuel cells (SOFCs).

La0.70Ca0.30MnO3 system has been prepared by solid state reaction method for cathode of solid oxide fuel cell applications. The structural studies have been investigated by X-Ray diffraction method and the experimental results have confirmed that the prepared system has been well crystallized into single phase, crystal structure is orthorhombic and size of the particle has been calculated to be 0.35 μm. The surface morphology has been studied by scanning electron microscopy which confirmed that grain sizes are irregular, non uniform and randomly oriented. Archimedes principle has been used to investigate the density of the prepared material. Thermal properties of the system confirmed its stability at high temperature and thermal expansion coefficient well matched with other cell components. The dielectric as well as impedance properties have been investigated at different ranges of temperature and frequency. Electrical conductivity of the prepared system has been found to be more than 100 S/cm as well as obtained value of activation energy signifies that the synthesized system is suitable for cathode of solid oxide fuel cell applications.

Perovskite solid solutions (La0.70Ca0.30)(FexMn1-x)O3 where x = 0.01, 0.20, 0.30 and 0.40 ceramics were synthesized by solid state reaction route. The structural studies were carried by X-Ray diffraction method and the observed results have indicated that all the prepared samples were crystallized into single phase. The surface morphology was studied by Scanning Electron Microscopy and the images have revealed that grain size has increased with the increasing concentration of Fe. Archimedes principle was used to calculate the density of all the sintered samples and the density values were observed to be in increasing order. The impedance and dielectric properties have been characterized at different ranges of temperature and frequency. The value of electrical conductivity were found to be more than 100 S cm-1 , which indicate that the synthesized material is suitable material for cathode of Solid Oxide Fuel Cell.