Local spin moment of LaCoO3 probed by a core hole Original Research Article

The electronic structures of the ground state and the 1s−1 core-hole state of high-spin cobalt oxide clusters are calculated. The calculated results indicate that the high-spin Co3+ oxide becomes low spin in the core-hole state. To check the validity of the present calculation, we have measured the high-resolution X-ray fluorescence spectra of the Co K–L3 (Kα1) line shape for various cobalt compounds using a double-crystal X-ray fluorescence spectrometer: Co(acac)2, Co(acac)3, CoF3, CoCl2, CoBr2, K3[Co(CN)6], CoO, Co3O4, LaCoO3, and Co (metal), where acac denotes CH3COCHCOCH3−. We conclude from the comparison of the calculations with the experimental results that the cobalt ion in LaCoO3 at room temperature is high-spin state in spite that the reported spin state of this perovskite is different among the probing methods. The implications of the spin-flip shake-down process for the interpretation of the core-level X-ray photoelectron spectra, X-ray absorption spectra, and X-ray fluorescence spectra are discussed.