Chemical Ordering and Epitaxy in Relaxor and Ferroelectric PbSc_(0.5)Nb_(0.5)O_3 Thin Films

摘要

Thin films of relaxor ferroelectric PbSc_(0.5)Nb_(0.5)O_3 were deposited by in situ pulsed laser ablation at 825-975 K onto a La_(0.5)Sr_(0.5)CoO_3 (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-2 theta-, 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.