Thermoelectric properties of the brownmillerite oxide Ca2-yLayCo2-xAlxO5

Wataru Kobayashi, Akira Satake, Ichiro Terasaki

    Research output: Contribution to journalArticle

    11 Citations (Scopus)

    Abstract

    We prepared the brownmillerite oxide Ca2-yLayCo2-xAlxO5 and found that it was an n-type conductor. The thermopower and the resistivity of the single crystal are respectively -90 μ V/K and 68 mΩcm along the ab direction at 440 K, which suggest relatively good thermoelectrical properties, compared with other transition-metal oxides. Their temperature dependences are of activation type, and the activation energies are 0.2 eV for the resistivity and 0.04 eV for the thermopower. These energies differ by one order in magnitude, which implies that a polaron dominates the charge transport. The sign of the thermopower of the polycrystals changes from negative to positive at 500 K, indicating that holes are excited thermally to decrease the magnitude of thermopower.

    Original languageEnglish
    Pages (from-to)3025-3028
    Number of pages4
    JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
    Volume41
    Issue number5 A
    Publication statusPublished - 2002 May

    Fingerprint

    Thermoelectric power
    electrical resistivity
    Oxides
    oxides
    polycrystals
    metal oxides
    conductors
    transition metals
    activation
    activation energy
    temperature dependence
    single crystals
    Polycrystals
    Transition metals
    Charge transfer
    Activation energy
    Chemical activation
    Single crystals
    energy
    Temperature

    Keywords

    • Layered cobalt oxide
    • Thermal conductivity
    • Thermoelectric material

    ASJC Scopus subject areas

    • Physics and Astronomy (miscellaneous)

    Cite this

    Thermoelectric properties of the brownmillerite oxide Ca2-yLayCo2-xAlxO5. / Kobayashi, Wataru; Satake, Akira; Terasaki, Ichiro.

    In: Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers, Vol. 41, No. 5 A, 05.2002, p. 3025-3028.

    Research output: Contribution to journalArticle

    @article{dbbc0705d0a04fb3acd845db78036803,
    title = "Thermoelectric properties of the brownmillerite oxide Ca2-yLayCo2-xAlxO5",
    abstract = "We prepared the brownmillerite oxide Ca2-yLayCo2-xAlxO5 and found that it was an n-type conductor. The thermopower and the resistivity of the single crystal are respectively -90 μ V/K and 68 mΩcm along the ab direction at 440 K, which suggest relatively good thermoelectrical properties, compared with other transition-metal oxides. Their temperature dependences are of activation type, and the activation energies are 0.2 eV for the resistivity and 0.04 eV for the thermopower. These energies differ by one order in magnitude, which implies that a polaron dominates the charge transport. The sign of the thermopower of the polycrystals changes from negative to positive at 500 K, indicating that holes are excited thermally to decrease the magnitude of thermopower.",
    keywords = "Layered cobalt oxide, Thermal conductivity, Thermoelectric material",
    author = "Wataru Kobayashi and Akira Satake and Ichiro Terasaki",
    year = "2002",
    month = "5",
    language = "English",
    volume = "41",
    pages = "3025--3028",
    journal = "Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes",
    issn = "0021-4922",
    publisher = "Japan Society of Applied Physics",
    number = "5 A",

    }

    TY - JOUR

    T1 - Thermoelectric properties of the brownmillerite oxide Ca2-yLayCo2-xAlxO5

    AU - Kobayashi, Wataru

    AU - Satake, Akira

    AU - Terasaki, Ichiro

    PY - 2002/5

    Y1 - 2002/5

    N2 - We prepared the brownmillerite oxide Ca2-yLayCo2-xAlxO5 and found that it was an n-type conductor. The thermopower and the resistivity of the single crystal are respectively -90 μ V/K and 68 mΩcm along the ab direction at 440 K, which suggest relatively good thermoelectrical properties, compared with other transition-metal oxides. Their temperature dependences are of activation type, and the activation energies are 0.2 eV for the resistivity and 0.04 eV for the thermopower. These energies differ by one order in magnitude, which implies that a polaron dominates the charge transport. The sign of the thermopower of the polycrystals changes from negative to positive at 500 K, indicating that holes are excited thermally to decrease the magnitude of thermopower.

    AB - We prepared the brownmillerite oxide Ca2-yLayCo2-xAlxO5 and found that it was an n-type conductor. The thermopower and the resistivity of the single crystal are respectively -90 μ V/K and 68 mΩcm along the ab direction at 440 K, which suggest relatively good thermoelectrical properties, compared with other transition-metal oxides. Their temperature dependences are of activation type, and the activation energies are 0.2 eV for the resistivity and 0.04 eV for the thermopower. These energies differ by one order in magnitude, which implies that a polaron dominates the charge transport. The sign of the thermopower of the polycrystals changes from negative to positive at 500 K, indicating that holes are excited thermally to decrease the magnitude of thermopower.

    KW - Layered cobalt oxide

    KW - Thermal conductivity

    KW - Thermoelectric material

    UR - http://www.scopus.com/inward/record.url?scp=0036578205&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=0036578205&partnerID=8YFLogxK

    M3 - Article

    AN - SCOPUS:0036578205

    VL - 41

    SP - 3025

    EP - 3028

    JO - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes

    JF - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes

    SN - 0021-4922

    IS - 5 A

    ER -