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Description
To evaluate radiation tolerance, 25 mol% Gd₂O₃-doped CeO₂ nano powders were synthesized by a sol-gel combustion route and sintered at 800°C, 1000°C, and 1300°C to obtain different grain sizes. The pellets were irradiated with 100 MeV iodine ions to simulate fission-fragment damage, and structural and electronic changes were examined using synchrotron GIXRD, Raman spectroscopy, EXAFS, XPS, and electron microscopy. Smaller grain-sized samples (800°C) exhibited more significant irradiation-induced degradation compared to larger grain-sized samples (1300°C), although both maintained their fluorite cubic structure at the highest ion fluence (1×10¹⁴ ions/cm²). EXAFS indicated Ce–O bond relaxation, Gd-coordination changes, and redistribution of oxygen vacancies. Raman peak broadening suggested vacancy-related defect complexes, and XPS revealed shifts in Ce³⁺/Ce⁴⁺ ratios and charge redistribution. First-principles GGA-PBE calculations support vacancy stabilization and local bonding rearrangement. The results highlight clear grain-size-dependent radiation response in Gd-doped CeO₂ and its relevance for nuclear and space applications.
Footnotes
- Supported by UGC fellowship and experimental facilities at JNU, IUAC, RRCAT, and BARC.
- GANIL proposal acceptance indicates future extension of this work.
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