We have obtained Co 2p, Rh 3d, Ir 4f, and valence-band x-ray photoemission spectra of Ca 3Co 2O 6, Ca 3CoRhO 6, Ca 3CoIrO 6, and Sr 3ZnIrO 6 in order to determine the valence states of Co. The spectral features are consistent with the picture that Co is in the trivalent state at both trigonal prismatic and octahedral sites with high- and low-spin states, respectively, in Ca 3Co 2O 6, whereas Co is in the high-spin Co 2+ state for Ca 3CoRhO 6 and Ca 3CoIrO 6. This conclusion resolves a recent controversy regarding the valence and spin states of Co in Ca 3Co 2O 6 and Ca 3CoRhO 6. This is the first x-ray photoemission spectroscopic study of this family of oxides.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 2005 2 1|
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