Investigation of the microstructural features of SrCo0.8Fe0.2O3−δ perovskite

Belen'kaya, I. M.; Cherepanova, Svetlana V.; Nemudry, A. P.

doi:10.1007/s10008-012-1716-5

Cited by 8 publications

(4 citation statements)

References 23 publications

(36 reference statements)

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“…It is interesting that a similar diffraction pattern (Fig. 10b) was observed previously for the SrCo 0.8 Fe 0.2 O 2.66 sample obtained by slow cooling in air (Belenkaya et al, 2012). In this case, an increase in the oxygen stoichiometry of SrCo 0.8 -Fe 0.2 O 2.5+x is also accompanied by compositional disorder as a result of the formation of non-isovalent B 4+ cations and oxygen excess.…”

Section: Discussionsupporting

confidence: 84%

Ferroelasticity of SrCo_0.8Fe_0.2O_3–δperovskite-related oxide with mixed ion–electron conductivity

2015

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A group-theoretical analysis was carried out to determine the possible orientation states of domains formed as a result of the 'perovskitebrownmillerite' phase transition in SrCo 0.8 Fe 0.2 O 2.5 oxide with mixed ionelectron 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 h010i BM and h101i 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 3À with compositional disorder may be considered (in terms of its microstructural features) a 'relaxor ferroelastic'.

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Section: Discussionsupporting

confidence: 84%

Ferroelasticity of SrCo_0.8Fe_0.2O_3–δperovskite-related oxide with mixed ion–electron conductivity

2015

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“…7-9). Previously, we have shown 43,44 that this kind of diffraction pattern is associated with nanostructuring of nonstoichiometric doped perovskites: local ordering of oxygen vacancies in 90 nanodomains coherently jointed between themselves and domains with perovskite structure. It results in a coherent lattice where the long-range order is characterized by the perovskite subcell a p whereas the From the viewpoint of theoretical group analysis, the ferroelastic phase transition from the cubic phase P 1 with S.G. Pm 3m (order of group: 48) to tetragonal T phase with S.G. P4/ mmm (order of group: 16) should be accompanied by the formation of three types of 90 domains.…”

Section: 2mentioning

confidence: 85%

Phase transitions and microstructure of ferroelastic MIEC oxide SrCo_0.8Fe_0.2O_2.5 doped with highly charged Nb/Ta(v) cations

2015

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“…The difference is due to the separation into two phases (perovskite and brownmillerite) which is known to occur with the formation of immiscible coexisting nanostructured domains of both compositions. 11,16,19,32 On increasing the temperature, the perovskite phase width increases and the miscibility gap narrows. Above 900°C (Figures 2 and 3), the miscibility gap is small and the observed stoichiometry is almost the same on heating and cooling.…”

Section: Resultsmentioning

confidence: 99%

“…In Figure , different values of δ are observed on increasing and decreasing p O 2 at T ≤850°C. The difference is due to the separation into two phases (perovskite and brownmillerite) which is known to occur with the formation of immiscible coexisting nanostructured domains of both compositions . On increasing the temperature, the perovskite phase width increases and the miscibility gap narrows.…”

Section: Discussionmentioning

confidence: 99%

Determination of oxygen nonstoichiometry in SrFeO_3−δ by solid‐state Coulometric titration

Yoo

et al. 2017

J Am Ceram Soc

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The oxygen nonstoichiometry of SrFeO3−δ was determined by solid‐state Coulometric titration at 750°C‐1040°C and 10−18≤pO2(atm)≤0.5. At T≤850°C, a hysteresis in the oxygen nonstoichiometry (δ) isotherms indicates the presence of a two‐phase region corresponding to a mixture of a perovskite and an oxygen vacancy ordered phase. The variation of δ with temperature at fixed pO2 values and the variation of log(pO2) with reciprocal temperature at fixed δ are reported. The pO2 at the p‐n transition in the electrical conductivity increases as the temperature increases, and the transition in the conductivity isotherm occurs at a composition of SrFeO2.505(1) at 950°C and SrFeO2.508(1) at 900°C. Since strontium exclusively occupies the A‐site, a simple point defect model that assumes noninteracting defects can describe the isotherms but only at 1040°C; nonideal behavior is observed at lower temperatures. The partial molar thermodynamic quantities for oxygen in SrFeO3−δ were determined.

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Investigation of the microstructural features of SrCo0.8Fe0.2O3−δ perovskite

Cited by 8 publications

References 23 publications

Ferroelasticity of SrCo_0.8Fe_0.2O_3–δperovskite-related oxide with mixed ion–electron conductivity

Ferroelasticity of SrCo_0.8Fe_0.2O_3–δperovskite-related oxide with mixed ion–electron conductivity

Phase transitions and microstructure of ferroelastic MIEC oxide SrCo_0.8Fe_0.2O_2.5 doped with highly charged Nb/Ta(v) cations

Determination of oxygen nonstoichiometry in SrFeO_3−δ by solid‐state Coulometric titration

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Investigation of the microstructural features of SrCo0.8Fe0.2O3−δ perovskite

Cited by 8 publications

References 23 publications

Ferroelasticity of SrCo0.8Fe0.2O3–δperovskite-related oxide with mixed ion–electron conductivity

Ferroelasticity of SrCo0.8Fe0.2O3–δperovskite-related oxide with mixed ion–electron conductivity

Phase transitions and microstructure of ferroelastic MIEC oxide SrCo0.8Fe0.2O2.5 doped with highly charged Nb/Ta(v) cations

Determination of oxygen nonstoichiometry in SrFeO3−δ by solid‐state Coulometric titration

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Ferroelasticity of SrCo_0.8Fe_0.2O_3–δperovskite-related oxide with mixed ion–electron conductivity

Ferroelasticity of SrCo_0.8Fe_0.2O_3–δperovskite-related oxide with mixed ion–electron conductivity

Phase transitions and microstructure of ferroelastic MIEC oxide SrCo_0.8Fe_0.2O_2.5 doped with highly charged Nb/Ta(v) cations

Determination of oxygen nonstoichiometry in SrFeO_3−δ by solid‐state Coulometric titration