Four novel co-precipitation procedures for the synthesis of lanthanum-strontium manganites

Lanthanum-strontium manganites were synthesized using co-precipitation method with a reverse micellar microemulsion. Either oxalic acid, sodium hydroxide or tetramethylammonium hydroxide was used for the precipitation of precursor cations in a form that was subsequently calcined under various conditions in order to obtain perovskite manganite phase. Correlations between the properties of the synthesized powder and the calcination conditions have been put forth. The properties of the microemulsion-assisted synthesized material were compared with the samples prepared by following the supposedly similar chemical recombinations in bulk solutions, with an aim to challenge the fact that microemulsions in general have only templating effects on the morphology of co-precipitated powder. TEM measurements, X-ray diffraction analyses and magnetic measurements were used in order to gain an insight into the mentioned difference, which is an important one for the future understanding of the role that reverse micelles play in the processes of materials synthesis.