A Sequential Electron Doping for Quadruple Perovskite Oxides ACu3Co4O12(A = Ca, Y, Ce)

Ikuya Yamada, Takao Odake, Atsushi Tanaka, Yuichi Okazaki, Fumito Toda, Yuta Ishii, Toshifumi Taniguchi, Shogo Kawaguchi, Atsushi Hariki

Research output: Contribution to journalArticle

Abstract

A novel quadruple perovskite oxide CeCu3Co4O12 has been synthesized in high-pressure and high-temperature conditions of 12 GPa and 1273 K. Rietveld refinement of the synchrotron X-ray powder diffraction pattern reveals that this oxide crystallizes in a cubic quadruple perovskite structure with the 1:3-type ordering of Ce and Cu ions at the A-site. X-ray absorption spectroscopy analysis demonstrates the valence-state transitions in the ACu3Co4O12 series (A = Ca, Y, Ce) from Ca2+Cu3+3Co3.25+4O12 to Y3+Cu3+3Co3+4O12 to Ce4+Cu2.67+3Co3+4O12, where the electrons are doped in the order from B-site (Co3.25+ → Co3+) to A′-site (Cu3+ → Cu2.67+). This electron-doping sequence is in stark contrast to the typical B-site electron doping for simple ABO3-type perovskite and quadruple perovskites CaCu3B4O12 (B = V, Cr, Mn), further differing from the monotonical A′-site electron doping for Na1-xLaxMn3Ti4O12 and A′- and B-site electron doping for AMn3V4O12 (A = Na, Ca, La). The differences in the electron-doping sequences are interpreted by rigid-band models, proposing a wide variety of electronic states for the complex transition-metal oxides containing the multiple valence-variable ions.

Original languageEnglish
JournalInorganic chemistry
DOIs
Publication statusAccepted/In press - 2020

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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    Yamada, I., Odake, T., Tanaka, A., Okazaki, Y., Toda, F., Ishii, Y., Taniguchi, T., Kawaguchi, S., & Hariki, A. (Accepted/In press). A Sequential Electron Doping for Quadruple Perovskite Oxides ACu3Co4O12(A = Ca, Y, Ce). Inorganic chemistry. https://doi.org/10.1021/acs.inorgchem.0c00184