Magneto-thermoelectric measurements on epitaxial Heusler alloy thin films

ORAL

Abstract

Full Heusler compounds with the composition Co2Mn(Al,Si) are of interest due to their nearly half-metallic behavior. We have measured the Seebeck and anomalous Nernst coefficients in epitaxial MgO(001)/Co2MnAlxS1-x thin films using a novel all-electrical device fabricated through straightforward top-down photolithography techniques. Because the scattering rate cancels out in expressions for the thermoelectric coefficients (to first approximation), they can provide more direct information about the electronic structure than is accessible using only ordinary magneto-transport. Among our samples, we found Co2MnAl to have the largest anomalous Nernst coefficient of -4 Am-1K-1 at room temperature, which is larger than the value of -2 Am-1K-1measured in bulk polycrystalline Fe [S. J. Watzman et al., Phys. Rev. B 94, 144407 (2016)] . We discuss how these measurements can be applied as a probe of a material’s spin polarization, so that they can be used as a tool for optimizing magneto-electronic properties of quaternary Heusler alloys.

*This work was funded by NSF under DMR 17-1708287.

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Presenters

  • Aaron Breidenbach

    • Physics and Astronomy, University of Minnesota

Authors

  • Paul Crowell

    • Physics and Astronomy, University of Minnesota
    • University of Minnesota
    • School of Physics and Astronomy, University of Minnesota

  • Timothy A Peterson

    • Physics and Astronomy, University of Minnesota
    • Physics, University of Minnesota

  • Anthony McFadden

    • University of California, Santa Barbara
    • ECE and Materials, University of California, Santa Barbara
    • University of California Santa Barbara

  • Chris Palmstrom

    • University of California, Santa Barbara
    • University of California - Santa Barbara
    • University of California Santa Barbara
    • Electrical & Computer Engineering, University of California, Santa Barbara
    • ECE and Materials, University of California, Santa Barbara
    • Dept. of ECE, University of California Santa Barbara
    • Materials Department, University of California, Santa Barbara
    • Materials Engineering, University of California, Santa Barbara
    • University of California Santa Barbara, Materials Engineering
    • Departments of Electrical and Computer Engineering and Materials, University of California, Santa Barbara

  • Aaron Breidenbach

    • Physics and Astronomy, University of Minnesota

  • Han Yu

    • Physics and Astronomy, University of Minnesota