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Title: Thermal conductivity control by oxygen defect concentration modification in reducible oxides: The case of Pr{sub 0.1}Ce{sub 0.9}O{sub 2−δ} thin films

We demonstrate the impact on thermal conductivity of varying the concentration of oxygen vacancies and reduced cations in Pr{sub 0.1}Ce{sub 0.9}O{sub 2−δ} thin films prepared by pulsed laser deposition. The oxygen vacancy concentration is controlled by varying the oxygen partial pressure between 1 × 10{sup −4} and 1 atm at 650  °C. Corresponding changes in the oxygen non-stoichiometry (δ) are monitored by detecting the lattice parameters of the films with high-resolution X-ray diffraction, while the thermal properties are characterized by time-domain thermoreflectance measurements. The films are shown to exhibit a variation in oxygen vacancy content, and in the Pr{sup 3+}/Pr{sup 4+} ratio, corresponding to changes in δ from 0.0027 to 0.0364, leading to a reduction in the thermal conductivity from k = 6.62 ± 0.61 to 3.82 ± 0.51 W/m-K, respectively. These values agree well with those predicted by the Callaway and von Baeyer model for thermal conductivity in the presence of point imperfections. These results demonstrate the capability of controlling thermal conductivity via control of anion and cation defect concentrations in a given reducible oxide.
Authors:
;  [1] ; ;  [2] ; ;  [3]
  1. Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
  2. Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
  3. Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
Publication Date:
OSTI Identifier:
22283147
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CATIONS; CERIUM OXIDES; CONCENTRATION RATIO; ENERGY BEAM DEPOSITION; LASER RADIATION; LATTICE PARAMETERS; OXYGEN; PARTIAL PRESSURE; PRASEODYMIUM COMPOUNDS; PRASEODYMIUM IONS; PULSED IRRADIATION; THERMAL CONDUCTIVITY; THIN FILMS; VACANCIES; X-RAY DIFFRACTION