Crystal chemistry and ion‐irradiation resistance of Ln₂ZrO₅ compounds with Ln = Sm, Eu, Gd, and Tb

Abstract

The previously unattained fabrication of single phase Ln 2 ZrO 5 (Ln = Sm, Eu, Gd, and Tb) compounds via relatively low sintering temperature (1400 • C) is achieved in this study using a coprecipitation method. The crystal structures have been investigated by neutron, synchrotron X-ray powder diffraction, and electron diffraction techniques. While the general long-range structure may be well described by the defect-fluorite type structure with Fm 3m symmetry, electron diffraction has highlighted a complex underlying modulated structure that varies between each compound. These compounds have been tested for ion-irradiation response using in situ 1 MeV krypton ions and transmission electron microscopy characterization. None of the compounds undergo a crystalline to amorphous transition, even holding at 50 K. Both the underlying fluorite and modulated superstructures are little affected by the irradiation. However, some atomic rearrangements are observed in the postirradiated electron diffraction patterns for the Sm 2 ZrO 5 specimen.