Ion irradiation experiments and quantitative x-ray diffraction analysis were used to demonstrate that the lattice and structure behave very differently in a complex oxide, $\delta \text{−}{\mathrm{Sc}}_4{\mathrm{Hf}}_3{\mathrm{O}}_{12}$, under irradiation. Analysis of the structure reveals that with increasing fluence, the characteristic $c/a$ ratio for the $\delta$ phase converges to that of an ideal fluorite phase, whereas locally it produces a metaphase consisting of frozen nanoscale structures having bixbyite-like flavor that increase the overall stability and radiation response of the apparent long-range oxygen-deficient average fluorite structure.

• Received 12 June 2020
• Accepted 14 August 2020

DOI:https://doi.org/10.1103/PhysRevMaterials.4.093605