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Structures and properties of the perovskite-type compounds Na1-xSrxNbO3 (0.1<x<0.9) – from insulating to metallic conductivityстатья
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: Istomin S.Ya, Svensson G., Koehler J.
- Журнал: Journal of Solid State Chemistry
- Том: 167
- Год издания: 2002
- Издательство: Elsevier B.V.
- Местоположение издательства: Netherlands
- Первая страница: 7
- Последняя страница: 16
- DOI: 10.1006/jssc.2002.9603
- Аннотация: Reduced perovskite-type compounds with compositions Na1����xSrxNbO3 ð0:1rxr0:9Þ have been synthesized. X-ray powder diffraction (XRD) studies for the 0:2rxr0:7 phases indicate a tetragonal structure (P4/mbm) with unit-cell para- meters aEO2 ���� aper; cEaper (the subscript ‘per’ refers to the cubic perovskite structure), and for x 1⁄4 0:8 and 0.9, the space group P4/mmm was found with aEaper ; cEaper : Structure refinements based on XRD and neutron diffraction data using the Rietveld technique confirmed this for Na1����xSrxNbO3, 0:3rxr0:7 and x 1⁄4 0:5; 0.6, respectively. Selected-area and convergent beam electron diffraction studies show that the crystallites of x 1⁄4 0:2 and 0.3 phases in fact have the GdFeO3- type structure (space group Pnma and unit-cell parameters aEO2 ���� aper ; bE2 ���� aper ; cEO2 ���� aper ) while crystallites in the 0:4rxr0:9 samples consist of intergrown domains between this orthorhombic structure and the tetragonal structure (P4/ mbm). The reason for the appearance of two phases is due to local variations in the Na/Sr content within the crystal- lites. Measurements of the magnetic susceptibilities show that the itinerant behavior in the samples Na1����xSrxNbO3 increases with the carrier concentration. The resistivity measurements indicate that an insulator–metal transition takes place between x 1⁄4 0:5 and 0.6. The samples with x 1⁄4 0:4 and 0.5 exhibit a complex temperature dependence of the resistivity with a maximum around 70 K.
- Добавил в систему: Истомин Сергей Яковлевич
Прикрепленные файлы
| № | Имя | Описание | Имя файла | Размер | Добавлен |
|---|---|---|---|---|---|
| 1. | Полный текст | NaSrNbO3.pdf | 333,6 КБ | 10 ноября 2012 [richard2012] |