Structural phase transitions in CdTiO3

The reconstructive phase transition from the ilmenite-like CdTiO3 modification to the perovskite modification is investigated thoroughly. It is revealed that the reconstructive transition is determined by size effects, results in the formation of the closest packing of the ilmenite CdTiO3 structure, and is irreversible with a decrease in temperature. The perovskite CdTiO3 modification undergoes displacive structural phase transitions at temperatures of 110, 220, and 380°C. The first displacive phase transition is isostructural, whereas the second and third transitions are associated with rotations of oxygen octahedra.