Synthesis and investigation of structural and electronic properties of Pr1−xCaxFeO3 (0⩽x⩽0.2) compounds

Single-phase powder compounds of Pr1−xCaxFeO3 (x=0, 0.1 and 0.2) have been synthesized by combustion method using as starting material the corresponding metal nitrates and glycine. The compounds were characterized by X-ray diffraction (XRD), Fe K-edge X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) of core level of Pr 3d, Fe 2p, Ca 2p and O 1s. Rietveld profile refinement technique was employed to analyze the powder diffraction data. All the three compounds showed orthorhombic structure with systematic reduction in lattice parameters. The distortion in FeO6 octahedra also reduced as x increased. The chemical shift of Fe K-edge showed that the Fe is in 3+ state in PrFeO3 and its effective charge increased on Ca doping. XPS studies revealed that the ionic state of Pr, Fe and Ca is close to the ionic state of these elements in Pr2O3, Fe2O3 and CaO, respectively. On substituting Ca for Pr, effective charge on Pr and Fe increased whereas that on O decreased. Change in exchange splitting consistent with the increased effective charge was also observed on Ca doping.