Structural characterisation of the perovskite series Sr_0.9-xCa_xCe_0.1MnO₃: Influence of the Jahn-Teller effect

Fifteen perovskite-type compounds Sr_0.9-xCa_xCe_0.1MnO₃, x=0-0.9 in steps as fine as 0.05, have been synthesised by solid state methods, and the room temperature structures characterised using X-ray synchrotron powder diffraction. At low Ca contents (x≤0.45) the structures are tetragonal in space group I4/mcm and at high Ca contents (x≥0.55) the compounds are orthorhombic in space group Pbnm. At room temperature these two phases co-exist in the compound with x=0.5. XANES measurements show the Ce to be present as Ce⁴⁺ in all the oxides. High temperature structures are reported for selected members.