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The crystal structure features of Ca-substituted ferrites La1-xCaxFeO3статья Исследовательская статья
Дата последнего поиска статьи во внешних источниках: 15 апреля 2026 г.
- Авторы: Sedykh V.D., Rusakov V.S., Rybchenko O.G., Gapochka A.M., Matsnev M.E., Toporkova A.A., Ivanov A.I., Kulakov V.I.
- Журнал: Physics of the Solid State
- Том: 67
- Номер: 9
- Год издания: 2025
- Издательство: Pleiades Publishing, Ltd
- Местоположение издательства: Road Town, United Kingdom
- Первая страница: 1698
- Последняя страница: 1707
- Аннотация: The crystal structure features of the Ca-substituted lanthanum ferrite La1−xCaxFeO3−γ have been studied as the Ca concentration dependence (x = 0.0, 0.3, 0.5, 0.7, 1.0) using X-ray diffraction analysis and Mossbauer spectroscopy. It has been investigated both the synthesized samples and the samples annealed at 650 C in vacuum, when Fe4+ ions are completely transferred to Fe3+. When the Ca concentration is x < 0.5, the Pbnm orthorhombic phase is formed. At higher Ca concentrations (x > 0.5) — the vacancy-ordered Grenier (LaCa2Fe3O8) and Brounmillerite (Ca2Fe2O5) phases are formed. The portion of each valence Fe state, the number of oxygen vacancies, and oxygen content were determined using the low-temperature Mossbauer data for all the samples studied. The synthesized sample with x = 0.5 has a maximum number of Fe4+ ions. The Fe ions are in a trivalent state for the initial and last numbers of the concentration series, x = 0 (LaFeO3) and x = 1 (Ca2Fe2O5). In the synthesized samples, the relation of contributions of the different Fe3+ ion structural states to the Mossbauer spectrum has been shown to change towards the oxygen environments characteristic of the vacancy-ordered phases when increasing Ca concentration. The vacuum annealing (when there are no Fe4+ ions) results in the formation effective local environment of Fe ions.
- Добавил в систему: Русаков Вячеслав Серафимович
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