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2021
Journal Article
Titel
High-temperature electrical and thermal transport properties of polycrystalline PdCoO2
Abstract
The layered delafossite PdCoO2 has been predicted to be one of very few materials with a thermopower that is highly anisotropic and switches sign between different crystallographic directions. These properties are of interest for various applications, but have been difficult to verify because sufficiently large crystals have not been available. We report measurements of the high-temperature electrical resistivity, thermal conductivity, and thermopower of phase-pure PdCoO2 powder compacts prepared by a highly Pd-efficient synthesis route. While the electronic transport of the polycrystalline samples is dominated by that of the Pd planes, the thermopower exhibits a well-defined deviation from the in-plane character at temperatures above 600K, which is indicative of opposing trends in the Seebeck coefficients within and perpendicular to the delafossite layers. The experimental data are consistently described by a combination of effective-medium models based on the main axes transport quantities. The results support the predicted ambipolar thermopower anisotropy in PdCoO2.
Author(s)
Gibbs, A.S.
Max-Planck Institute for Solid State Research; ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory
Kaya, P.
Max-Planck Institute for Solid State Research; Aalen University, Materials Research Institute (IMFAA)
Xie, W.
Institute for Material Science, University of Stuttgart; Department of Material Science, Technical University of Darmstadt;
Xiao, X.
Institute for Material Science, University of Stuttgart; Department of Material Science, Technical University of Darmstadt;
Takagi, H.
Max-Planck Institute for Solid State Research; Institute for Functional Matter and Quantum Technologies, University of Stuttgart; Department ofPhysics, University of Tokyo