Novel structural features and phase transition behaviour of (Sr1-xCax)TiO3:: II.: X-ray diffraction studies

Results of a careful XRD study of the room temperature structure of (Sr1-xCax)TiO3 (SCT) with 0.0 less than or equal to x less than or equal to 1.0 are presented to show that the structure of SCT is CaTiO3- (CT-) like for x greater than or equal to 0.12. High temperature XRD studies on the phase transition behaviour of SCT with 0.12 less than or equal to x less than or equal to 0.21 show the existence of an intermediate phase in between the room temperature orthorhombic phase and the high temperature cubic phase. This is analogous to the phase transition behaviour of pure CT and is attributed to the softening of the R-25 and M-3 point phonon modes.