The interaction of multifold polar orderings in Ba-doped Sr0.7Ca0.3TiO3

A series of polycrystalline Sr0.7−xCa0.3BaxTiO3 (SCBT) (0.0 ≤ x ≤ 0.25) samples were synthesized through solid-state reaction method, and their microstructural, anti-ferroelectric (AFE), ferroelectric (FE), dielectric, and phase transition properties were investigated. With the incorporation of Ba2+ at Sr2+ site, the AFE polar phase (x = 0.0) has been sharply changed, experiencing AFE state, enhanced FE state, cooperative FE state, and normal FE state, owing to the competition and coupling interactions of different polar orderings in SCBT system. Note that excellent FE behavior has been found in the cooperative FE state. In addition, the critical region has been proposed in the T − x phase diagram.

T − x phase diagram for current SCBT system. The closed black squares represent the AFE transition point. The open red squares show the FE transition point. The solid lines are the fitting results for Tm of AFE and T′mT′m of FE. Hatching region suggests the critical region.Figure optionsDownload as PowerPoint slideHighlights
► Polycrystalline Sr0.7−xCa0.3BaxTiO3 (SCBT) (0.0 ≤ x ≤ 0.25) were synthesized.
► The AFE polar phase (x = 0.0) presented sharp changes with Ba-doping in SCBT.
► Excellent FE behavior has been found in the cooperative FE state.
► T − x phase diagram has been given and the critical region has been proposed.