Spin-polarized Seebeck effect at the nanoscale measured with scanning tunneling thermovoltage microscopy

ORAL

Abstract

Spin caloritronic effects have gained recent interest due to, e.g., potential low-power applications of magnetic tunnel junctions in which a temperature gradient-driven tunneling of electrons gives rise to a spin-dependent thermovoltage due to the Seebeck effect. Here, we report spatial mapping of the spin-resolved thermovoltage in a tunneling junction formed by ferromagnetic Co islands on a Cu(111) substrate and the magnetic tip of a scanning tunneling microscope. Our measurements reveal variations of the thermovoltage as function of spin polarization, island size, and stacking orientation of the islands with respect to the substrate. This method allows to reveal nanoscopic heterogeneities of both, the magnetic structures and the spin-dependent thermoelectric power.

*This research was performed at the Center for Nanophase Materials Sciences which is a DOE Office of Science User Facility.

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Presenters

  • Jewook Park

    • Institute for Basic Science, Pohang, Republic of Korea

Authors

  • Jewook Park

    • Institute for Basic Science, Pohang, Republic of Korea

  • Felix Luepke

    • Carnegie Mellon University
    • Carnegie Mellon Univ
    • Oak Ridge National Lab

  • Jun Jiang

    • Department of Physics and Quantum Theory Project, University of Florida
    • University of Florida
    • Department of Physics, Center for Molecular Magnetic Quantum Materials and Quantum Theory Project, University of Florida
    • Physics, University of Florida

  • Xiaoguang Zhang

    • University of Florida
    • Department of Physics, University of Florida
    • Department of Physics, Center for Molecular Magnetic Quantum Materials and Quantum Theory Project, University of Florida
    • Physics, University of Florida

  • An-Ping Li

    • Oak Ridge National Laboratory
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Oak Ridge National Lab