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Publications::
R. Egoavil, S. Hühn, M. Jungbauer, N. Gauquelin, A. Béché,a G. Van Tendeloo, J. Verbeeck and V. Moshnyaga Phase problem in the B-site ordering of La2CoMnO6: impact on structure and magnetism Nanoscale 7 (2015), 9835 Epitaxial double perovskite La2CoMnO6 (LCMO) films were grown by metalorganic aerosol deposition on
SrTiO3(111) substrates. A high Curie temperature, TC = 226 K, and large magnetization close to saturation,
MS(5 K) = 5.8μB/f.u., indicate a 97% degree of B-site (Co,Mn) ordering within the film. The Co/Mn ordering
was directly imaged at the atomic scale by scanning transmission electron microscopy with energy-dispersive
X-ray spectroscopy (STEM-EDX). Local electron-energy-loss spectroscopy (EELS) measurements
reveal that the B-sites are predominantly occupied by Co2+ and Mn4+ ions in quantitative agreement with
magnetic data. Relatively small values of the (1/2 1/2 1/2) superstructure peak intensity, obtained by X-ray
diffraction (XRD), point out the existence of ordered domains with an arbitrary phase relationship across
the domain boundary. The size of these domains is estimated to be in the range 35–170 nm according to
TEM observations and modelling the magnetization data. These observations provide important information
towards the complexity of the cation ordering phenomenon and its implications on magnetism in
double perovskites, and similar materials. View/Download |
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