Structures and phase diagram for the system CaTiO3–La2/3TiO3

High-resolution neutron and synchrotron X-ray powder diffraction have been used to examine various compositions across the system (1−x)CaTiO3−xLa2/3TiO3. The structures at room temperature were determined according to composition: in Pbnm for 0⩽x⩽0.5, Ibmm for 0.50.5 in the current study based on our high-resolution neutron diffraction data. From in situ measurements to identify structures above room temperature, an approximate composition–temperature phase diagram has been constructed, involving four temperature-induced phase transitions: Pbnm→I4/mcm, Ibmm→I4/mcm, I4/mcm→Pm3¯m and Cmmm→P4/mmm.

Graphical AbstractPhase diagram for Ca(1−x)La3x/2TiO3 based on transition temperatures obtained from in situ neutron and synchrotron X-ray powder diffraction studies: depending on whether or not we have in-phase and/or out-of-phase octahedral tilting, whether we have long-range cation/vacancy ordering (the degree of ordering is indicated by shading), six distinct structures occur.Figure optionsDownload full-size imageDownload as PowerPoint slide