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HERO ID
1741841
Reference Type
Journal Article
Title
Structure, electrical conducting and thermal expansion properties of Ln(0.6)Sr(0.4)Co(0.2)Fe(0.8)O(3) (Ln = La, Pr, Nd, Sm) pprovskite-type complex oxides
Author(s)
Xu, Q; Huang, DP; Chen, Wen; Zhang, F; Wang, B
Year
2007
Is Peer Reviewed?
Yes
Journal
Journal of Alloys and Compounds
ISSN:
0925-8388
Volume
429
Issue
1-2
Page Numbers
34-39
DOI
10.1016/j.jallcom.2006.04.005
Web of Science Id
WOS:000244673100007
Abstract
Fine and uniform Ln(0.6)Sr(0.4)Co(0.2)Fe(0.8)O(3) (Ln = La, Pr, Nd, Sm) powders with a perovskite phase were produced using a glycine-nitrate process. The structure, electrical conducting and thermal expansion properties of the resulting ceramics were investigated. The results indicate that replacing La3+ by smaller lanthanide cations led to a change in crystal structure from rhombohedral to orthorhombic symmetry and a decrease of the pseudo-cubic lattice constant. It was found that the electrical conducting properties decrease with reducing lanthanide cation size. Compared with La0.6Sr0.4Co0.2Fe0.8O3, the degradation of the electrical conducting properties in Pr0.6Sr0.4Co0.2Fe0.8O3 and Nd0.6Sr0.4Co0.2Fe0.08O3 is not pronounced, whereas the electrical conducting properties of Sm0.6Sr0.4Co0.2Fe0.8O3 decline to an unsatisfactory level. There is an evident increase in thermal expansion at high temperatures for all the compositions. This is attributed to a chemically induced lattice expansion due to oxygen lose and formation of oxygen vacancies. Pr0.6Sr0.4Co0.2Fe0.8O3 and Nd0.6Sr0.4Co0.2Fe0.8O3 present relatively low thermal expansion coefficient values of 14.2 x 10(-6) and 13.2 x 10(-6) K-1 averaged between 100-750 and 100-700 degrees C, respectively. (c) 2006 Elsevier B.V. All rights reserved.
Keywords
ceramics; crystal structure; electrical transport; thermal expansion
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