Structure and thermoelectric properties of Ca 2-xSr xFeMoO 6 (0 ≤ x ≤ 0.3) double-perovskite oxides

Tohru Sugahara, Ngo Van Nong, Michitaka Ohtaki

    研究成果: ジャーナルへの寄稿記事

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    抄録

    The thermoelectric properties of double perovskite-type oxides Ca 2FeMoO 6 are investigated in terms of Sr substitution at the A site of the oxides. The electrical conductivity, σ, of Ca 2-xSr xFeMoO 6 (0 ≤ x ≤ 0.3) showed a metallic behavior, decreasing monotonically from ca. 10 3 S cm -1 at room temperature to ca. 10 2 S cm -1 at 1250 K. At room temperature, although the σ values of the oxides increased with increasing substitution level, x, the σ values maintained almost the same values at high temperature range of 1000-1250 K. The absolute values of the Seebeck coefficient, S, for the samples at x < 0.3 abruptly increase at around 1000 K. The Rietveld refinement of the XRD patterns of the oxides indicated that the anti-site defects in the oxides decreased with increasing Sr concentration. The power factor, S 2σ, of the oxides largely increased with increasing temperature; the S 2σ value of Ca 2FeMoO 6 was ca. 0.35 mW mK -2 at 1200 K, the largest value of all the samples in this study. Although the thermal conductivity, κ, of the oxides generally decreased from ca. 3.5 to 4.5 W mK -1 at room temperature to ca. 2-3 W mK -1 at 1050 K, the sample at x = 0.3 showed the lowest and most T-independent κ values, implying that the relative increase in the temperature is independent from the phonon-impurity scattering caused by the A-site substitution. The power factor of the oxides increased above 900 K; thereby, the dimensionless figure of merit, ZT = (S 2σ/κ)T, significantly increased at the same temperature range. The largest ZT value of 0.15 was observed for Ca 2FeMoO 6, Ca 1.9Sr 0.1FeMoO 6, and Ca 1.8Sr 0.2FeMoO 6 at 1250 K.

    元の言語英語
    ページ(範囲)630-634
    ページ数5
    ジャーナルMaterials Chemistry and Physics
    133
    発行部数2-3
    DOI
    出版物ステータス出版済み - 4 16 2012

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    Perovskite
    Oxides
    oxides
    Substitution reactions
    Temperature
    substitutes
    room temperature
    Rietveld refinement
    Seebeck coefficient
    perovskite
    Seebeck effect
    figure of merit
    temperature
    Thermal conductivity
    thermal conductivity
    Scattering
    Impurities
    impurities
    Defects
    electrical resistivity

    All Science Journal Classification (ASJC) codes

    • Materials Science(all)
    • Condensed Matter Physics

    これを引用

    Structure and thermoelectric properties of Ca 2-xSr xFeMoO 6 (0 ≤ x ≤ 0.3) double-perovskite oxides. / Sugahara, Tohru; Van Nong, Ngo; Ohtaki, Michitaka.

    :: Materials Chemistry and Physics, 巻 133, 番号 2-3, 16.04.2012, p. 630-634.

    研究成果: ジャーナルへの寄稿記事

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    title = "Structure and thermoelectric properties of Ca 2-xSr xFeMoO 6 (0 ≤ x ≤ 0.3) double-perovskite oxides",
    abstract = "The thermoelectric properties of double perovskite-type oxides Ca 2FeMoO 6 are investigated in terms of Sr substitution at the A site of the oxides. The electrical conductivity, σ, of Ca 2-xSr xFeMoO 6 (0 ≤ x ≤ 0.3) showed a metallic behavior, decreasing monotonically from ca. 10 3 S cm -1 at room temperature to ca. 10 2 S cm -1 at 1250 K. At room temperature, although the σ values of the oxides increased with increasing substitution level, x, the σ values maintained almost the same values at high temperature range of 1000-1250 K. The absolute values of the Seebeck coefficient, S, for the samples at x < 0.3 abruptly increase at around 1000 K. The Rietveld refinement of the XRD patterns of the oxides indicated that the anti-site defects in the oxides decreased with increasing Sr concentration. The power factor, S 2σ, of the oxides largely increased with increasing temperature; the S 2σ value of Ca 2FeMoO 6 was ca. 0.35 mW mK -2 at 1200 K, the largest value of all the samples in this study. Although the thermal conductivity, κ, of the oxides generally decreased from ca. 3.5 to 4.5 W mK -1 at room temperature to ca. 2-3 W mK -1 at 1050 K, the sample at x = 0.3 showed the lowest and most T-independent κ values, implying that the relative increase in the temperature is independent from the phonon-impurity scattering caused by the A-site substitution. The power factor of the oxides increased above 900 K; thereby, the dimensionless figure of merit, ZT = (S 2σ/κ)T, significantly increased at the same temperature range. The largest ZT value of 0.15 was observed for Ca 2FeMoO 6, Ca 1.9Sr 0.1FeMoO 6, and Ca 1.8Sr 0.2FeMoO 6 at 1250 K.",
    author = "Tohru Sugahara and {Van Nong}, Ngo and Michitaka Ohtaki",
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    AU - Van Nong, Ngo

    AU - Ohtaki, Michitaka

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    N2 - The thermoelectric properties of double perovskite-type oxides Ca 2FeMoO 6 are investigated in terms of Sr substitution at the A site of the oxides. The electrical conductivity, σ, of Ca 2-xSr xFeMoO 6 (0 ≤ x ≤ 0.3) showed a metallic behavior, decreasing monotonically from ca. 10 3 S cm -1 at room temperature to ca. 10 2 S cm -1 at 1250 K. At room temperature, although the σ values of the oxides increased with increasing substitution level, x, the σ values maintained almost the same values at high temperature range of 1000-1250 K. The absolute values of the Seebeck coefficient, S, for the samples at x < 0.3 abruptly increase at around 1000 K. The Rietveld refinement of the XRD patterns of the oxides indicated that the anti-site defects in the oxides decreased with increasing Sr concentration. The power factor, S 2σ, of the oxides largely increased with increasing temperature; the S 2σ value of Ca 2FeMoO 6 was ca. 0.35 mW mK -2 at 1200 K, the largest value of all the samples in this study. Although the thermal conductivity, κ, of the oxides generally decreased from ca. 3.5 to 4.5 W mK -1 at room temperature to ca. 2-3 W mK -1 at 1050 K, the sample at x = 0.3 showed the lowest and most T-independent κ values, implying that the relative increase in the temperature is independent from the phonon-impurity scattering caused by the A-site substitution. The power factor of the oxides increased above 900 K; thereby, the dimensionless figure of merit, ZT = (S 2σ/κ)T, significantly increased at the same temperature range. The largest ZT value of 0.15 was observed for Ca 2FeMoO 6, Ca 1.9Sr 0.1FeMoO 6, and Ca 1.8Sr 0.2FeMoO 6 at 1250 K.

    AB - The thermoelectric properties of double perovskite-type oxides Ca 2FeMoO 6 are investigated in terms of Sr substitution at the A site of the oxides. The electrical conductivity, σ, of Ca 2-xSr xFeMoO 6 (0 ≤ x ≤ 0.3) showed a metallic behavior, decreasing monotonically from ca. 10 3 S cm -1 at room temperature to ca. 10 2 S cm -1 at 1250 K. At room temperature, although the σ values of the oxides increased with increasing substitution level, x, the σ values maintained almost the same values at high temperature range of 1000-1250 K. The absolute values of the Seebeck coefficient, S, for the samples at x < 0.3 abruptly increase at around 1000 K. The Rietveld refinement of the XRD patterns of the oxides indicated that the anti-site defects in the oxides decreased with increasing Sr concentration. The power factor, S 2σ, of the oxides largely increased with increasing temperature; the S 2σ value of Ca 2FeMoO 6 was ca. 0.35 mW mK -2 at 1200 K, the largest value of all the samples in this study. Although the thermal conductivity, κ, of the oxides generally decreased from ca. 3.5 to 4.5 W mK -1 at room temperature to ca. 2-3 W mK -1 at 1050 K, the sample at x = 0.3 showed the lowest and most T-independent κ values, implying that the relative increase in the temperature is independent from the phonon-impurity scattering caused by the A-site substitution. The power factor of the oxides increased above 900 K; thereby, the dimensionless figure of merit, ZT = (S 2σ/κ)T, significantly increased at the same temperature range. The largest ZT value of 0.15 was observed for Ca 2FeMoO 6, Ca 1.9Sr 0.1FeMoO 6, and Ca 1.8Sr 0.2FeMoO 6 at 1250 K.

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