Thermal conductivity of A-site doped pyrochlore oxides studied by molecular-dynamics simulation

    Authors

    P. K. Schelling

    Comments

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    Abbreviated Journal Title

    Comput. Mater. Sci.

    Keywords

    Thermal diffusion; Diffusive energy transport; Phonon-defect; interactions; Disordered crystalline alloys; Molecular-dynamics; simulation; STABILIZED ZIRCONIA; HIGH TEMPERATURES; LANTHANUM; GADOLINIUM; TRANSPORT; SAMARIUM; Materials Science, Multidisciplinary

    Abstract

    Molecular-dynamics simulations are used to compute thermal-conductivity of pyrochlore solid solutions based on Gd(2)Zr(2)O(7) with substitution on the A-site by La, Y, and Sm ions. Simulation results and theoretical predictions are compared to experimental data where available. We find that simulations predict that the thermal conductivity decreases due to point-defect scattering, but by a much smaller amount than what is observed in experiment. At higher temperatures, we predict that additional point-defect scattering results in very small decreases in the thermal conductivity. While both mass and bond disorder play a role in reducing the thermal conductivity, the simulations suggest that large differences in ionic sizes on the A-site result in biggest effect. We explore the results using a theoretical model based on prior work due to B. Abeles, and find in some cases significant disagreement with our simulated results. The results presented here suggest that additional point-defect disorder will likely be of rather limited value for low thermal-conductivity applications. Finally, we discuss some of the possible explanations for disagreement with experimental observations. (C) 2010 Published by Elsevier B.V.

    Journal Title

    Computational Materials Science

    Volume

    48

    Issue/Number

    2

    Publication Date

    1-1-2010

    Document Type

    Article

    Language

    English

    First Page

    336

    Last Page

    342

    WOS Identifier

    WOS:000277634300014

    ISSN

    0927-0256

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