Synthesis, structure and microstructure of the layered compounds Lnl-xSrl+xCoO4 (Ln: La, Nd and Gd)

By using the nitrate decomposition method in the presence of KNO3, we have been able to enlarge the compositional range of the solid solution of the layered compounds with K2NiF4 Structure Ln(1-x)Sr(1+x)CoO(4) (Ln: La, Nd, Gd) to 0 less than or equal to x less than or equal to 0.40 in the case of Ln = La, to 0 less than or equal to x less than or equal to 0.30 for Ln = Nd and to 0 less than or equal to x less than or equal to 0.20 for Ln = Gd. In this paper we present the results of their structural characterization by means of powder X-ray diffraction and Rietveld analysis as a function of composition (x) and the rare earth (Ln), information that has been complemented by the results obtained from electron diffraction and transmission electron microscopy. (C) 2003 Elsevier SAS. All rights reserved.