PHOTOEMISSION AND ELECTRON-ENERGY-LOSS-SPECTROSCOPY STUDY OF BARUO3

Core- and valence-level photoemission spectra of the hexagonal perovskite BaRuO3 are reported. Valence-region photoemission shows that BaRuO3 is a metallic material with a well-defined cutoff in the energy-distribution curve at the Fermi energy, while in electron-energy-loss spectroscopy a plasmon-loss peak is observed at 1.0 eV. Comparison with previously published data for CaRuO3 and SrRuO3 shows that electron correlation becomes progressively less important in the series CaRuO3-SrRuO3-BaRuO3. © 1995 The American Physical Society.