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Powders of La0.7Ba0.3Co1− y Fe y O3, LBCF, y=0.0 to 1.0, were prepared by thermal decomposition of metal polymerized complex solutions. Thermal and chemical analyses of cation concentrations were used to confirm the desired composition sintered at 900°C. Powder X-ray diffraction data indicate that all compositions possess the perovskite structure. Cubic unit cell parameters increase with increasing iron content except for y=0.3, which was explained in terms of the average valencies and charge neutrality of Fe and Co ions and oxygen ion deficiency. The electrical properties such as conductivity, dielectric constant and dielectric loss factor of the LBCF samples were studied as a function of frequency (100Hz–1MHz) and temperature (293–625K). Iron substituted samples exhibit semiconductor behavior with decreased electrical conductivity values compared to that of the free Fe sample. The possible conduction mechanisms were discussed. Dielectric studies show apparent high dielectric behavior, which was explained by the double layer capacitor model.

The characterization of the polycrystalline La 0.7 Ba 0.3 MnO 3−δ (LBM) and La 0.7 Ba 0.3 Mn 0.9 Li 0.1 O 3−δ (LBMLi) samples synthesized via the polymerized complex, sol-gel technique indicates the formation of cubic perovskite crystal structure of both samples by sintering at 900 • C for 2 h. Substitution of Mn by Li having smaller ionic radius, leads to decrease the lattice constant and the cell volume which gives rise to a small shift and small intensity difference of the XRD patterns. A nanocrystalline structure of LBMLi with particles in the size range of 30-100 nm was obtained. The temperature dependence of electrical conductivity and magnetic susceptibility of LBM and LBMLi were studied. The smaller electrical conductivity values and the calculated magnetic properties of Li substituted the Mn in LBM sample were investigated.