The interplay and impact of strain and defect association on the conductivity of rare-earth substituted ceria

George F. Harrington, Lixin Sun, Bilge Yildiz, Kazunari Sasaki, Nicola H. Perry, Harry L. Tuller

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34 Citations (SciVal)


The effects of strain on the ionic conductivity of rare-earth substituted CeO 2 have been extensively studied, but the results have been inconsistent and focused upon the ‘optimised’ conductors such as Gd or Sm substituted CeO 2 where defect association is minimised. By thermally annealing epitaxial films deposited by pulsed laser deposition, we varied the strain systematically, whilst avoiding any influence from interfacial or grain boundary effects. The activation energy of the in-plane conductivity was found to increase with increasing compressive biaxial strain, which was quantitatively in excellent agreement with previous computational and experimental studies. These results provide a much needed quantitative consensus on the effects of lattice strain on ionic transport. Furthermore, we demonstrate that the change in the activation energy for Yb-substituted CeO 2 is around three times that for Gd or La substitutions for the same applied strain, indicating the important role played by defect association. These results have significant implications for ionic transport at reduced or ambient temperatures, where changes in conductivity due to strain may be several orders of magnitude larger for ‘non-optimised’ conductors compared with ‘optimised’ conductors. We rationalise our results by considering the defect-defect interactions in these materials and through force-field calculations.

Original languageEnglish
Pages (from-to)447-458
Number of pages12
JournalActa Materialia
Publication statusPublished - 31 Mar 2019

Bibliographical note

Funding Information:
GFH thanks R. De Souza and J. Kilner for illuminating discussions, and J. Santiso for assistance with the XRD RSM analysis. GFH also gratefully acknowledges financial support from a Kakenhi Grant-in-Aid for Encouragement of Young Scientists (B) Award (No. JP16K18235 ). The authors are also grateful for support from the Progress 100 program of Kyushu University , and the International Institute for Carbon-Neutral Energy Research ( WPI-I2CNER ), both supported by MEXT , Japan, and the Center of Innovation Science and Technology based Radical Innovation and Entrepreneurship Program (COI Program), by the Japan Science and Technology Agency (JST). L. Sun, B. Yildiz and H. L. Tuller acknowledge support for their research from the Department of Energy, Basic Energy Sciences under award number DE-SC0002633 (Chemomechanics of Far-From-Equilibrium Interfaces).

Publisher Copyright:
© 2019 Acta Materialia Inc.


  • Ceria
  • Ionic diffusion
  • Lattice strain
  • Point defects
  • Thin films

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys


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