Irradiation-Induced Defect Formation and Damage Accumulation in Single Crystal CeO₂


The accumulation of irradiation-induced disorder in single crystal CeO2 has been investigated over a wide range of ion fluences. Room temperature irradiations of epitaxial CeO2 thin films using 2 MeV Au2+ ions were carried out up to a total fluence of 1.3x1016 cm-2 Post-irradiation disorder was characterized using ion channeling Rutherford backscattering spectrometry (RBS/C) and confocal Raman spectroscopy. The Raman measurements were interpreted by means of a phonon confinement model, which employed rigid ion calculations to determine the phonon correlation length in the irradiated material. Comparison between the dose dependent changes in correlation length of the Raman measurements and the Ce disorder fraction from RBS/C provides complementary quantitative details on the rate of point and extended defect formation on the Ce and O sub-lattices over a broad range of ion fluences. Raman measurements, which are significantly more sensitive than RBS/C at low doses, reveal that the nucleation rate of defects is highest below 0.1 displacements per atom (dpa). Comparison between Raman and RBS/C measurements suggests that between 0.1 and 10 dpa the damage evolution is characterized by modest growth of point defects and/or small clusters, while above 10 dpa the preexisting defects rapidly grow into extended clusters and/or loops.


Nuclear Engineering and Radiation Science


The authors would like to thank Ke Jin and Haizhou Xue for operating the accelerator in the Ion Beam Materials Laboratory during the irradiations and ion beam analysis measurements. This research was performed using funding received from the DOE Office of Nuclear Energy's Nuclear Energy University Programs 12-3528 .

Keywords and Phrases

Defects; Gold; Gold compounds; Ions; Irradiation; Phonons; Point defects; Rutherford backscattering spectroscopy; Single crystals; Confocal Raman spectroscopy; Damage Accumulation; Displacements per atoms; Irradiated materials; Irradiation-induced defects; Phonon confinement model; Point and extended defects; Rutherford back-scattering spectrometry; Cerium compounds

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Article - Journal

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Publication Date

01 Jan 2018