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Influence of oxygen vacancies on core‐shell formation in solid solutions of (Na,Bi)TiO 3 and SrTiO 3
Author(s) -
Steiner Sebastian,
Heldt Jonas,
Sobol Oded,
Unger Wolfgang,
Frömling Till
Publication year - 2021
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17845
Subject(s) - strontium titanate , materials science , oxygen , acceptor , strontium , solid solution , homogeneity (statistics) , vacancy defect , diffusion , oxide , chemical physics , chemical engineering , crystallography , nanotechnology , chemistry , condensed matter physics , thermodynamics , thin film , metallurgy , physics , statistics , mathematics , organic chemistry , engineering
Solid solutions of (Na,Bi)TiO 3 (NBT) and SrTiO 3 (ST) are materials of interest for high‐strain or high‐energy density capacitor applications. Often, they exhibit chemical heterogeneity and develop core‐shell structures during regular solid‐state synthesis with an NBT‐rich core. In this case, the NBT forms first so that the strontium needs to diffuse into the material to reach chemical homogeneity. Depending on the presence of core‐shell structures, the electrical properties can vary drastically. In this work, we rationalize the effect of variations in oxygen vacancy concentration by Fe‐acceptor and Nb‐donor doping. It can be shown that a diffusion couple of strontium and oxygen is responsible for chemical homogenization and that the oxygen vacancy content can control the formation of a core‐shell structure.