Premium
Ferroelasticity of SrCo 0.8 Fe 0.2 O 3–δ perovskite‐related oxide with mixed ion–electron conductivity
Author(s) -
Belenkaya I.,
Matvienko A.,
Nemudry A.
Publication year - 2015
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576714027770
Subject(s) - brownmillerite , perovskite (structure) , crystal twinning , materials science , crystallography , oxide , mineralogy , tantalate , phase (matter) , ferroelectricity , texture (cosmology) , microstructure , phase transition , analytical chemistry (journal) , condensed matter physics , chemistry , metallurgy , dielectric , physics , chromatography , optoelectronics , organic chemistry , artificial intelligence , computer science , image (mathematics)
A group‐theoretical analysis was carried out to determine the possible orientation states of domains formed as a result of the `perovskite–brownmillerite' phase transition in SrCo 0.8 Fe 0.2 O 2.5 oxide with mixed ion–electron conductivity (MIEC). The results of the theoretical analysis agree with the experimental data obtained in the study of the SrCo 0.8 Fe 0.2 O 2.5 microstructure by means of transmission electron microscopy. Brownmillerite SrCo 0.8 Fe 0.2 O 2.5 (BM) has a lamellar texture composed of 90° twins 60–260 nm in size; the 〈010〉 BM and 〈101〉 BM directions are linked through twinning in accordance with the predictions of the group‐theoretical analysis. The presence of twins and their switching under mechanical load provide evidence that the perovskite–brownmillerite phase transition in SrCo 0.8 Fe 0.2 O 2.5 is ferroelastic. Comparative analysis of the phenomena observed for ferroelectrics and MIEC oxides indicates their similarity based on the common nature of ferroelectricity and ferroelasticity, and allows us to suppose that nonstoichiometric SrCo 0.8 Fe 0.2 O 3−δ with compositional disorder may be considered (in terms of its microstructural features) a `relaxor ferroelastic'.