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Microstructure and defect investigations of the layered manganites La 2–2 x Ca 1+2 x Mn 2 O 7 ( x = 0.6, 0.8 and 0.9) by HREM
Author(s) -
Wang Yumei,
Yu Richeng
Publication year - 2009
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200824012
Subject(s) - crystallography , transmission electron microscopy , microstructure , perovskite (structure) , materials science , electron diffraction , high resolution transmission electron microscopy , diffraction , x ray crystallography , manganite , mineralogy , condensed matter physics , chemistry , nanotechnology , physics , ferromagnetism , optics
The microstructure and defects of the n = 2 Ruddlesden–Popper manganites La 2–2 x Ca 1+2 x Mn 2 O 7 ( x = 0.6, 0.8 and 0.9) were investigated by electron diffraction and high‐resolution transmission electron microscopy. Besides the predominant n = 2 layered structure in the examined compounds, intergrowths with different number of the perovskite‐like layers were observed. Intergrowth of n = 1 (K 2 NiF 4 ‐type) was observed only in x = 0.9 sample. Intergrowths with n ≥ 5, essential perovskite microdomains or inclusions, were seen in the x = 0.8 and 0.6 samples. The type of defects in x = 0.8 sample is much richer than that in x = 0.6 and 0.9 samples and two rare types were observed and analyzed. Some of edge dislocations in the x = 0.6 specimen were presented. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)