Variations in an oleic acid and metal nitrate emulsion under calcination on the structural and morphology of LaAlO3 nanopowders

In this paper, we describe variations in an oleic acid and metal nitrate emulsion during the process of forming superfine LaAlO3 crystallites from the mixture of oleic acid and metal nitrate precursors. The influence of oleic acid to metal nitrate ratio (ol/mn) on the phase and morphology were characterized by Differential thermal analysis (DTA-TGA), X-ray diffraction (XRD) and transmission electron microscopy (TEM). X-ray diffraction analysis of the powders with ol/mn ≤1 indicated the formation of pure rhombohedral LaAlO3 at 800 °C. The optimal ratio of the oleic acid to metal nitrate for preparing fine LaAlO3 nanopowders of 29 nm was 0.5. The TEM micrographs indicated morphological change (sphere, cube, triangle, etc.) as the oleic acid to metal nitrate ratio increases from 0.5 to 2.