1. Determining absolute Seebeck coefficients from relative thermopower measurements of thin films and nanostructures.
- Author
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Mason, S. J., Hojem, A., Wesenberg, D. J., Avery, A. D., and Zink, B. L.
- Subjects
SEEBECK coefficient ,THIN films ,THERMOELECTRIC effects ,METALLIC films ,NANOELECTROMECHANICAL systems ,SEEBECK effect ,MAGNONS - Abstract
Measurements of thermoelectric effects such as the Seebeck effect, the generation of electric field in response to an applied thermal gradient, are important for a range of thin films and nanostructures used in nanoscale devices subject to heating. In many cases, a clear understanding of the fundamental physics of these devices requires knowledge of the intrinsic thermoelectric properties of the material, rather than the so-called "relative" quantity that comes directly from measurements and always includes contributions from the voltage leads. However, for a thin film or nanostructure, determining the absolute Seebeck coefficient, α abs , is challenging. Here, we first overview the challenges for measuring α abs and then present an approach for determining α abs for thin films from relative measurements made with a micromachined thermal isolation platform at temperatures between 77 and 350 K. This relies on a relatively simple theoretical description based on the Mott relation for a thin film sample as a function of thickness. We demonstrate this technique for a range of metal thin films, which show that α abs almost never matches expectations from tabulated bulk values, and that for some metals (most notably gold) even the sign of α abs can be reversed. We also comment on the role of phonon and magnon drag for some metal films. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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