In situ radiation damage studies of LaxSr1−3x∕2TiO3 perovskites

Seven perovskite samples in the LaxSr1−3x∕2TiO3 solid solution series were monitored in situ during irradiation with 1.0MeV Kr2+ ions using the intermediate voltage electron microscope-Tandem User Facility (IVEM) at Argonne National Laboratory. All the perovskites pass through the crystalline-amorphous transformation. However, the critical temperature for amorphisation Tc of the LaxSr1−3x∕2TiO3 perovskites varies nonlinearly with composition, decreasing from 394±3K for SrTiO3 to a minimum of 275±1K for La0.2Sr0.7TiO3, then increasing with composition again to 865±3K for La0.67TiO3. In combination with the work of previous authors, the electron microscopy results and IVEM data in this study suggest that there is a vacancy-assisted recovery mechanism in the cubic perovskites with compositions in the range 0<x<0.2 that may not be directly associated with the cubic-tetragonal phase transformation and that vacancy-enhanced amorphisation occurs for both cubic and orthorhombic perovskites with compositions in the range x=∼0.2–0.67.