Oxygen nonstoichiometry and defect equilibrium in electron doped Ca0.6-ySr0.4LayMnO3-δ

Goldyreva, E.I.; Leonidov, I.A.; Patrakeev, M.V.; Chukin, A.V.; Leonidov, I.I.; Kozhevnikov, V.L.

Статья опубликована в высокорейтинговом журнале

Информация о цитировании статьи получена из Web of Science, Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 24 июля 2019 г.

Авторы: Goldyreva E.I., Leonidov I.A., Patrakeev M.V., Chukin A.V., Leonidov I.I., Kozhevnikov V.L.
Журнал: Journal of Alloys and Compounds
Том: 638
Год издания: 2015
Издательство: Elsevier BV
Местоположение издательства: Netherlands
Первая страница: 44
Последняя страница: 49
DOI: 10.1016/j.jallcom.2015.03.048
Аннотация: The perovskite-like electron doped manganites Ca0.6−уSr0.4LaуMnO3−δ (0 ⩽ y ⩽ 0.15) were synthesized in order to study oxygen content variations with composition, temperature and oxygen partial pressure. The samples are characterized with orthorhombic Pnma structure at 0 < у < 0.1 and tetragonal I4/mcm structure at у ⩾ 0.13 according to room temperature powder X-ray diffraction (XRD). The high-temperature data of XRD in air show transition to cubic Pm-3m structure at heating above 550 °С. The variations of oxygen content in Ca0.6−уSr0.4LaуMnO3−δ with temperature and oxygen pressure were measured using thermogravimetry and coulometric titration at temperatures between 650 and 950 °С in the oxygen pressure range 10−4–0.7 atm. The oxygen nonstoichiometry δ changes in Ca0.6−уSr0.4LaуMnO3−δ are observed to considerably decrease with the increase in lanthanum content. In order to explain the nonstoichiometry data, a thermodynamic model is developed based on defect formation reactions 2Mn3+ + VO + ½O2 = 2Mn4+ + O2− and 2Mn4+ = Mn3+ + Mn5+. The respective equilibrium constants, defect formation enthalpies and entropies are obtained. The concentrations of different defects are calculated as functions of temperature, oxygen pressure and lanthanum content. The high-temperature conductivity measurements are carried out for independent verification of the suggested model.
Добавил в систему: Леонидов Иван Ильич

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Oxygen nonstoichiometry and defect equilibrium in electron doped Ca0.6-ySr0.4LayMnO3-δстатья

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