Electronic structures of LaCoO₃-based oxides studied by soft x-ray absorption spectroscopy under controlled temperatures and oxygen partial pressures

In situ soft X-ray absorption spectroscopic measurements were performed to evaluate electronic structures of LaCoO₃. X-ray absorption spectra at Co LII- and LIII-edges were measured under p(O₂) = 10^-4 bar at room temperature to 873 K. Depending on temperature, the shape and the peak energy of the absorption spectra were varied, indicating thermally induced spin state transition of Co³⁺ ion. The results demonstrated that our in situ soft X-ray absorption technique is an useful tool to investigate the electronic structures of components for solid oxide fuel cells under operating conditions.