Hierarchical domain structures associated with oxygen octahedra tilting patterns were observed in lead-free (Bi1/2Na1/2)TiO3 ceramics using aberration-corrected high-resolution transmission electron microscopy (HRTEM). Three types of domains are induced by distinct mechanisms: the "orientation-domain" is induced at micrometer scale formed by different tilting orientations of the oxygen octahedra, the "meso-chemical-domain" occurs at a few tens of nanometer scale by chemical composition variation on the A-site in the ABO3 perovskite structure, and the "nano-cluster-region" runs across several unit-cells with apparent A-site cation segregation with oxygen vacancies clustering around Na cations. Based on HRTEM amplitude contrast imaging (ACI), the correlation between the oxygen octahedral tilting pattern and compositional non-stoichiometry was established. The role of the hierarchical domain structure associated with the tilting patterns of the oxygen octahedra on the ferroelectric behavior of (Bi1/2Na1/2)TiO3 is also discussed.This is the Accepted Manuscript version of an article accepted for publication in Nanotechnology.
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The Version of Record is available online at DOI: 10.1088/1361-6528/aca030.
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