Effect of chemical pressure manipulation on the valence and thermoelectric properties of the intermediate valence compound YbCu2-xNixGe2

Gloria J. Lehr, Spencer L. Waldrop, Winston D. Carr, Donald T. Morelli

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    The thermoelectric properties of YbCu2Ge2 at low temperature are unremarkable, however it has been found to be an intermediate valence compound. Previous work has shown that manipulation of valence in such compounds by chemical pressure can have dramatic effects on the value of the Seebeck coefficient. YbCu2Ge2 has been found to exist in a nearly divalent, Yb2+, state at room temperature, which if increased towards 2.5 has the promise of increasing the Seebeck coefficient substantially. In this study a full solid solution of YbCu2Ge2 and YbNi2Ge2 was created to exert a chemical pressure on the Yb and shift the valence away from the nominally divalent. A dramatic increase in the Seebeck coefficient was found as well as a substantial decrease in the thermal conductivity. These effects resulted in a substantial increase in ZT at low temperature and further emphasized the applicability and large effect that valence manipulation can have on intermediate valence compounds.

    Original languageEnglish (US)
    Title of host publicationTri-Technology Device Refrigeration (TTDR)
    PublisherSPIE
    Volume9821
    ISBN (Electronic)9781510600621
    DOIs
    StatePublished - 2016
    EventTri-Technology Device Refrigeration (TTDR) - Baltimore, United States

    Other

    OtherTri-Technology Device Refrigeration (TTDR)
    CountryUnited States
    CityBaltimore
    Period4/19/164/20/16

    Profile

    Acetanilides
    Biogenic Amines
    Seebeck coefficient
    Temperature
    valence
    Manipulation
    Coefficient
    Alcuronium
    Seebeck effect
    manipulators
    Joint Loose Bodies
    Solid solutions
    Thermal conductivity
    Decrease
    solid solutions
    thermal conductivity
    shift
    room temperature

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Computer Science Applications
    • Electrical and Electronic Engineering
    • Applied Mathematics

    Cite this

    Lehr, G. J., Waldrop, S. L., Carr, W. D., & Morelli, D. T. (2016). Effect of chemical pressure manipulation on the valence and thermoelectric properties of the intermediate valence compound YbCu2-xNixGe2 In Tri-Technology Device Refrigeration (TTDR) (Vol. 9821). [98210H] SPIE. DOI: 10.1117/12.2228757

    Effect of chemical pressure manipulation on the valence and thermoelectric properties of the intermediate valence compound YbCu2-xNixGe2 . / Lehr, Gloria J.; Waldrop, Spencer L.; Carr, Winston D.; Morelli, Donald T.

    Tri-Technology Device Refrigeration (TTDR). Vol. 9821 SPIE, 2016. 98210H.

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Lehr, GJ, Waldrop, SL, Carr, WD & Morelli, DT 2016, Effect of chemical pressure manipulation on the valence and thermoelectric properties of the intermediate valence compound YbCu2-xNixGe2 in Tri-Technology Device Refrigeration (TTDR). vol. 9821, 98210H, SPIE, Tri-Technology Device Refrigeration (TTDR), Baltimore, United States, 19-20 April. DOI: 10.1117/12.2228757
    Lehr GJ, Waldrop SL, Carr WD, Morelli DT. Effect of chemical pressure manipulation on the valence and thermoelectric properties of the intermediate valence compound YbCu2-xNixGe2 In Tri-Technology Device Refrigeration (TTDR). Vol. 9821. SPIE. 2016. 98210H. Available from, DOI: 10.1117/12.2228757

    Lehr, Gloria J.; Waldrop, Spencer L.; Carr, Winston D.; Morelli, Donald T. / Effect of chemical pressure manipulation on the valence and thermoelectric properties of the intermediate valence compound YbCu2-xNixGe2 .

    Tri-Technology Device Refrigeration (TTDR). Vol. 9821 SPIE, 2016. 98210H.

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

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    abstract = "The thermoelectric properties of YbCu2Ge2 at low temperature are unremarkable, however it has been found to be an intermediate valence compound. Previous work has shown that manipulation of valence in such compounds by chemical pressure can have dramatic effects on the value of the Seebeck coefficient. YbCu2Ge2 has been found to exist in a nearly divalent, Yb2+, state at room temperature, which if increased towards 2.5 has the promise of increasing the Seebeck coefficient substantially. In this study a full solid solution of YbCu2Ge2 and YbNi2Ge2 was created to exert a chemical pressure on the Yb and shift the valence away from the nominally divalent. A dramatic increase in the Seebeck coefficient was found as well as a substantial decrease in the thermal conductivity. These effects resulted in a substantial increase in ZT at low temperature and further emphasized the applicability and large effect that valence manipulation can have on intermediate valence compounds.",
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