Perovskite-type BaXO3: its structural control by selection of ionic radius of X

The relationship between the structure of perovskite-type BaXO3 and the ionic radius of X was investigated. The size of the X ion was controlled by an appropriate combination of a pair of tetravalent ions such as (Ce, Tb), (Pr, Tb), (Pr, Zr) and (Tb, Zr). The phases examined were prepared by solid–solid reaction at 1500°C. Structural characterization was carried out by the powder X-ray diffraction technique. As a result, the change from orthorhombic to a rhombohedral-like structure takes place at 0.0745 nm for X, and another change from rhombohedral-like to a cubic structure occurs at around 0.0825 nm. These structural characteristics are discussed compared with perovskite-type (Ndx, Sm1−x)AlO3, which shows similar phenomena to BaXO3.