Chemical ordering and epitaxy in relaxor and ferroelectric PbSc0.5Nb0.5O3 thin films

Thin films of relaxor ferroelectric PbSc0.5Nb0.5O3 were deposited by in situ pulsed laser ablation at 825-975 K onto a La0.5Sr0.5CoO3 (001) conducting oxide bottom electrode on MgO(001). Crystalline phases, epitaxial relations, crystal perfection, and chemical B-site ordering were studied by x-ray diffraction theta-2theta-, phi- and omega-scans. The perovskite films were pseudocubic and with 'cube-on-cube' epitaxy. At low deposition temperatures, also other epitaxial relations were obtained. All films showed NaCl type (1:1) B-site ordering that did not depend markedly on the deposition temperature. The perfection of epitaxy, in-plane biaxial compressive strain, and lateral dimensions of crystal columns increased with deposition temperature. The correlation between microstructural features of the films and the relaxor-like or ferroelectric-type dielectric behavior of the films in the heterostructures was discussed.