Oxygen Nonstoichiometry and Thermodynamic Explanation of Large Oxygen-Deficient Ruddlesden–Popper Oxides LaxSr3−xFe2O7−δ

Yihan Ling, Fang Wang, Yusuke Okamoto, Takashi Nakamura, Koji Amezawa, A. Belik

    研究成果: Article査読

    8 被引用数 (Scopus)

    抄録

    The oxygen nonstoichiometry of large oxygen-deficient Ruddlesden–Popper oxides LaxSr3−xFe2O7−δ (LSFO7-x) (x = 0, 0.25, 0.5) was measured by the high-temperature gravimetry and the coulometric titration. In the composition series, the P(O2) dependencies exhibited typical plateaus at δ = (2−[LaSr])/2. Meanwhile, La0.5Sr2.5Fe2O7−δ showed the smallest oxygen nonstoichiometry and was the most thermochemically stable compound against P(O2), temperature, and the La content. Based on the defect equilibrium model and the statistical thermodynamic calculation derived oxygen nonstoichiometric data, the substitution of La for Sr-site can promote the forward reaction of oxygen incorporation, the backward reaction of the disproportionation of the charge carriers, and oxygen redistribution between the O1 and O3 sites, resulting in the reduction of oxygen-deficient and the lower decomposition P(O2). The obtained thermodynamic quantities of the partial molar enthalpy of oxygen, hO – h°O, and the partial molar entropy of oxygen, sO – s°O, calculated from the statistical thermodynamic calculation are in good agreement with those using the Gibbs–Helmholtz equation.

    本文言語English
    ページ(範囲)3792-3801
    ページ数10
    ジャーナルJournal of the American Ceramic Society
    99
    11
    DOI
    出版ステータスPublished - 2016 11 1

    ASJC Scopus subject areas

    • Ceramics and Composites
    • Materials Chemistry

    フィンガープリント 「Oxygen Nonstoichiometry and Thermodynamic Explanation of Large Oxygen-Deficient Ruddlesden–Popper Oxides La<sub>x</sub>Sr<sub>3−x</sub>Fe<sub>2</sub>O<sub>7−δ</sub>」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

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