Understanding the energetics of radiation-induced defects is critical to the development of next-generation materials for nuclear and other energy systems and for aerospace applications. However, it remains a challenge to experimentally characterize defect morphologies and energies, especially in regard to anion defects in irradiated oxides. Here, using a combination of advanced structural and calorimetric characterization techniques, we show that the energetic response of defects in ${\mathrm{CeO}}_2$ is strongly coupled to atomic disordering on the oxygen sublattice induced by energetic heavy ions. Fitting of calorimetric data yields an estimate of stored energy in the form of defects and microstrain. These results provide a means to calculate the efficiency of structural destabilization and aid in a better understanding of defect formation and annealing mechanisms in fluorite-structured materials subject to extreme conditions.

• Received 25 April 2018
• Revised 17 July 2018

DOI:https://doi.org/10.1103/PhysRevMaterials.2.093607