The charge compensation mechanisms in polycrystalline Pr 1-xCaxCoO3δ and Pr1-x Sr xCoOδ here synthesized by the solid-state reaction method have been investigated by analyzing the Pr-L3 and Co-K X-ray absorption near-edge structure (XANES) with the aid of first-principles calculations. The valence states of Pr ions in these materials were determined to be trivalent (Pr3) and independent of the concentration of alkaline-earth ions observed in the Pr-L3 XANES profile. The Co-K XANES spectra shifted to the higher-energy side with an increase in alkalineearth concentration and were examined in detail by first-principles calculations. Using calculated XANES results, we successfully determined that the valence state of Co ions is an intermediate value between 3+ and 4+ and increases with an increase in the concentration of alkaline-earth ions in Pr1-xAxCoO 3δ (A = Ca, Sr) accompanying oxygen vacancy.
ASJC Scopus subject areas
- Physics and Astronomy(all)