Structural and composition dependent transport properties of perovskite oxides La0.8R0.2Fe0.5Cr0.5O3 (R=La, Nd, Gd and Dy)

Perovskite oxides La0.8R0.2Fe0.5Cr0.5O3 (R=La, Nd, Gd and Dy) have been synthesized by solid state reaction method. The Rietveld analysis of the XRD data showed that the samples crystallize with orthorhombic structure in the space group Pbnm. The results of resistivity measurements revealed that all the samples show insulating behaviour throughout the temperature range studied. The electrical conduction in these polycrystalline samples can be described by the adiabatic small polaron hoping model, with an apparent increase of polaron activation energy with the substitution of heavier rare earth ion.