Electronic structure and magnetic states i studied by photoemission and x-ray-absorption spectroscopy

We have studied the effects of hole doping on the electronic structure of La(Formula presented)Sr(Formula presented)CoO(Formula presented) by photoemission and x-ray-absorption spectroscopy. The Co 2(Formula presented) core-level and the valence-band spectra show charge-transfer satellites, which have been more obviously observed in 3(Formula presented)-3(Formula presented) resonant-photoemission spectra. By Sr substitution for La in LaCoO(Formula presented), the valence-band spectra do not show rigid-band behavior but change systematically and reflect the semiconductor-to-metal transition which occurs with hole doping. Only small changes with (Formula presented) have been observed in the resonant-photoemission spectra. Combined with configuration-interaction cluster-model calculations, this observation suggests that the intermediate-spin state is realized in the ferromagnetic phase.