Effect of the Oxygen Content on the Local Environment of Fe Atoms in Anion-Deficient SrFeO3 – δ

Sedykh, V. D.; Rybchenko, O. G.; Некрасов, А. Н.; Koneva, I. E.; Kulakov, V. I.

doi:10.1134/s1063783419060210

Cited by 24 publications

(7 citation statements)

References 23 publications

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“…The obtained results of the change in the phase composition and structural perovskite-like ceramics depending on the concentration of the initial components are in good agreement with previous similar studies of strontium lanthanum ferrites obtained by various methods. Thus, for example, the results of the change in the phase composition with an increase in lanthanum concentration with the formation of the Sr2Fe2O5 phase with the brownmillerite structure, as well as the displacement of the LaSr2Fe3O8 phase and its replacement by the (La0.3Sr0.7)2FeO4 phase, are in good agreement with the results of studies [21,22] in which similar ceramics were obtained by the sol-gel method from strontium, iron, and lanthanum nitrates annealed at a temperature of 400-1300 °С. However, in contrast to works [21][22][23], these phase transformation processes occur at lower sintering temperatures (1000 °С), and it also makes it possible to control both size effects and phase concentration.…”

Section: Resultssupporting

confidence: 88%

Properties of Perovskite-like Lanthanum Strontium Ferrite Ceramics with Variation in Lanthanum Concentration

et al. 2022

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The purpose of this work is to study the effect of lanthanum (La) concentration on the phase formation, conductivity, and thermophysical properties of perovskite-like strontium ferrite ceramics. At the same time, the key difference from similar studies is the study of the possibility of obtaining two-phase composite ceramics, the presence of various phases in which will lead to a change in the structural, strength, and conductive properties. To obtain two-phase composite ceramics by mechanochemical solid-phase synthesis, the method of the component molar ratio variation was used, which, when mixed, makes it possible to obtain a different ratio of elements and, as a result, to vary the phase composition of the ceramics. Scanning electron microscopy, X-ray phase analysis, and impedance spectroscopy were used as research methods, the combination of which made it possible to comprehensively study the properties of the synthesized ceramics. Analysis of phase changes depending on lanthanum concentration change can be written as follows: (La0.3Sr0.7)2FeO4/LaSr2Fe3O8 → (La0.3Sr0.7)2FeO4/LaSr2Fe3O8/Sr2Fe2O5 → (La0.3Sr0.7)2FeO4/Sr2Fe2O5. Results of impedance spectroscopy showed that with an increase in lanthanum concentration from 0.10 to 0.25 mol in the synthesized ceramics, the value of the dielectric permittivity increases significantly from 40.72 to 231.69, the dielectric loss tangent increases from 1.07 to 1.29 at a frequency of 10,000 Hz, and electrical resistivity decreases from 1.29 × 108 to 2.37 × 107 Ω∙cm.

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Section: Resultssupporting

confidence: 88%

Properties of Perovskite-like Lanthanum Strontium Ferrite Ceramics with Variation in Lanthanum Concentration

et al. 2022

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“…The proportion of Fe valence states and the degrees of distortion around Fe ions are changed with oxygen content. This result is similar to that reported by Sedykh et al of the SrFeO 3-δ [33]. For electroneutrality in the BaFeO 3 -Cop and BaFeO 3 -Sol samples, oxygen de cient δ (oxygen vacancies) are created because of the conversion of unstable Fe 4+ into Fe 3.5+ and Fe 3+ ions [39].…”

Section: Xrd Sem and Dls Studiessupporting

confidence: 90%

“…The oxygen de cient (δ) values in the BaFeO 3 -Cop and BaFeO 3 -Sol samples are summarized in Table 2. From this table, it can be seen that the area of magnetic components of BaFeO 3 -Cop sample is higher than that of BaFeO 3 -Sol sample because of high oxygen de cient (δ) content [33,32]. The IS and QS values of paramagnetic components of BaFeO 3 -Cop sample is lower than that of BaFeO 3 -Sol sample because of the increase of oxygen de cient (δ) content [32].…”

Section: Mössbauer and Xps Studiesmentioning

confidence: 96%

“…The single peak and quadrupole doublet in the Mössbauer spectra of BaFeO 3 -Cop and BaFeO 3 -Sol samples (Fig. 4) are due to the presence of Fe ions in two different valence states in distorted octahedral sites with oxygen de cient [33,34]. The Mössbauer hyper ne parameters of the BaFeO 3 -Cop and BaFeO 3 -Sol samples are summarized in Table 2.…”

Section: Xrd Sem and Dls Studiesmentioning

confidence: 99%

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Effect of Synthesis Method on Antibacterial and Antibiofilm Activity Properties of BaFeO3-δ Perovskite Nanomaterials

khalaf

Abdel-Khalek

Askar

et al. 2021

Preprint

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BaFeO3-δ perovskite nanomaterials have been synthesized by two different methods: co-precipitation (Cop) and sol-gel (Sol) methods. Rietveld analysis of the X-Ray diffraction (XRD) shows that the samples are crystallized in rhombohedral perovskite structure with space group R3c. Scanning electron microscope (SEM) of these samples showed the agglomerations of various particles. Dynamic light scattering (DLS) showed that the average particle size of BaFeO3-Cop sample is larger than that of BaFeO3-Sol sample. The amount of oxygen deficient (δ) and the valence states of Fe ions in these samples were determined from Mössbauer spectroscopy. X-ray photoelectron spectroscopy (XPS) shows the elemental compositions and surface electronic states of these samples. The thermal, optical and magnetic properties of these samples depend on the amount of oxygen deficient (δ) and the valence states of Fe ions. Furthermore, the antibacterial and antibiofilm activity of these samples was systematically investigated. The present results suggest that BaFeO3-δ superparamagnetic perovskite can be used as antibacterial and antibiofilm agent.

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“…It can be seen that the XPS spectrum of O 1s for CaFeO 3-δ sample was deconvoluted into four individual peaks located at 529.29, 530.21, 531.6 and 534.17 eV. These peaks indicate the presence of four kinds of O states at the surface [30]. The peak at 529.29 eV can be attributed to the oxygen lattice (O latt : O 2-) of CaFeO 3-δ sample [21,31].…”

Section: Mössbauer and Xps Studiesmentioning

confidence: 98%

Study the Oxygen Vacancies and Fe Oxidation States in CaFeO3-δ Perovskite Nanomaterial

khalaf

Abdel-Khalek

Motawea

et al. 2021

Preprint

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In this study, CaFeO3-δ perovskite nanomaterial has been synthesized by sol-gel method. The oxygen vacancies and Fe oxidation states in CaFeO3-δ perovskite nanomaterial were investigated by using X-ray diffraction (XRD), Mössbauer spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetry analysis (TG), differential scanning calorimetric (DSC), and vibrating sample magnetometer (VSM). Rietveld analysis of the XRD shows that the sample was crystallized in orthorhombic perovskite structure with space group pcmn. The oxygen vacancies and oxidation states of Fe ions in CaFeO3-δ sample were determined from Mössbauer spectroscopy. XPS shows the presence of different states of Fe ions and oxygen vacancies in the surface of CaFeO3-δ sample. The thermal and magnetic properties of this sample have been investigated.

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Effect of the Oxygen Content on the Local Environment of Fe Atoms in Anion-Deficient SrFeO3 – δ

Cited by 24 publications

References 23 publications

Properties of Perovskite-like Lanthanum Strontium Ferrite Ceramics with Variation in Lanthanum Concentration

Properties of Perovskite-like Lanthanum Strontium Ferrite Ceramics with Variation in Lanthanum Concentration

Effect of Synthesis Method on Antibacterial and Antibiofilm Activity Properties of BaFeO3-δ Perovskite Nanomaterials

Study the Oxygen Vacancies and Fe Oxidation States in CaFeO3-δ Perovskite Nanomaterial

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