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Oxygen Nonstoichiometry of Tetragonal La2-xSrxCuO4-δ (x = 0.15-1.2) and in Situ XPS Studies at Elevated Temperaturesстатья
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: 18 июля 2013 г.
- Авторы: Alyoshin V.A., Romanova I.P., Mikhailova D., Oswald S., Senyshyn A., Ehrenberg H.
- Журнал: The Journal of Physical Chemistry A: Molecules, Clusters, and Aerosols
- Том: 114
- Номер: 51
- Год издания: 2010
- Издательство: American Chemical Society
- Местоположение издательства: United States
- Первая страница: 13362
- Последняя страница: 13369
- DOI: 10.1021/jp108648e
- Аннотация: The peculiarities of oxygen nonstoichiometry (δ) in tetragonal La2-xSrxCuO4-δ solid solution with x(Sr) ) 0.15-1.2 were studied by XRD, NPD, in situ high-temperature XPS, and chemical analysis. Temperature dependences of oxygen nonstoichiometry, δ ) δ(T), were obtained for different Sr contents at 1 bar of O2. Two types of charge compensation during replacement of lanthanum by strontium are discussed: an increase of the average copper oxidation state and a formation of oxygen vacancies. The average copper oxidation state V(Cu) exhibits a maximum of 2.32 at x(Sr) ) 0.6, while δ increases with x(Sr). Oxygen vacancies are unambiguously located on the 4c site ({CuO2} plane) for compositions with different strontium contents, which electronic state is described by the O 2p core electron peak at about 531 eV. Thermal stability of the solid solution in a vacuum is associated with the extraction of practically the entire oxygen from CuO2 layers and the formation of Cu+ at least in the near-surface region. The higher average copper oxidation state after synthesis in the Sr-rich phases in comparison with the Sr-poor compositions prevents oxygen removal and the formation of Cu+ and, therefore, stabilizes the structure during heating in a vacuum.
- Добавил в систему: Алёшин Владимир Алексеевич