Thermal Conductivity in Nanocrystalline Ceria Thin Films |
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| Authors: | Marat Khafizov In‐Wook Park Aleksandr Chernatynskiy Lingfeng He Jianliang Lin John J Moore David Swank Thomas Lillo Simon R Phillpot Anter El‐Azab David H Hurley |
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| Affiliation: | 1. Department of Materials Science and Engineering, Idaho National Laboratory, , Idaho Falls, Idaho, 83415;2. Department of Metallurgical and Materials Engineering, Colorado School of Mines, , Golden, Colorado, 80401;3. Department of Materials Science and Engineering, University of Florida, , Gainesville, Florida, 32611;4. Department of Engineering Physics, University of Wisconsin, , Madison, Wisconsin, 53706;5. Department of Nuclear Engineering, Purdue University, , West Lafayette, Indiana, 47907 |
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| Abstract: | The thermal conductivity of nanocrystalline ceria films grown by unbalanced magnetron sputtering is determined as a function of temperature using laser‐based modulated thermoreflectance. The films exhibit significantly reduced conductivity compared with stoichiometric bulk CeO2. A variety of microstructure imaging techniques including X‐ray diffraction, scanning and transmission electron microscopy, X‐ray photoelectron analysis, and electron energy loss spectroscopy indicate that the thermal conductivity is influenced by grain boundaries, dislocations, and oxygen vacancies. The temperature dependence of the thermal conductivity is analyzed using an analytical solution of the Boltzmann transport equation. The conclusion of this study is that oxygen vacancies pose a smaller impediment to thermal transport when they segregate along grain boundaries. |
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