Reentrant phase in nanoferroics induced by the flexoelectric and Vegard effects

摘要: We explore the impact of flexoelectric effect and Vegard (chemical pressure) on phase diagrams, long-range polar order related physical properties spherical ferroelectric nanoparticles using Landau-Ginzburg-Devonshire phenomenological approach. The synergy these effects can lead to remarkable changes nanoparticles' diagrams. In particular, a commonly expected transition from paraelectric at some small critical size is absent; so that loses its sense. Contrary, stabilization manifests itself by enhancement temperature polarization with particle decrease. Ferroelectric reentrant phenomenon was observed earlier in tetragonal BaTiO3 nanospheres radii 5-50 nm [Zhu et al., JAP 112, 064110 (2012)] stayed unexplained up now. Our calculations have shown mechanism exciting flexo-chemo-effect. Since spontaneous coupling, as well ion vacancies, should exist any nanostructured ferroelectrics, obtained analytical results be valid for many nanoferroelectrics, where phases appearance forecasted.