We here report the self-assembly of Li3Ni2NbO6 (LNNO) epitaxial disks with very low height/width aspect ratios. An epitaxial LNNO thin film is obtained at a substrate temperature (T-s) of 400 degrees C, using a pulsed laser deposition technique, and by increasing the T-s to 600 degrees C, Li3NbO4 epitaxial domains are formed inside the LNNO epitaxial film. Further increasing the T-s to 700 degrees C leads to the formation of LNNO disks (with diameters of a few micrometers and a typical height of similar to 100 nm) embedded in a Li3NbO4 film. Interestingly, transmission electron microscopy observations reveal that the LNNO disks are separated from the Li3NbO4 films by amorphous compounds, indicating the formation of a planar core-shell structure. Understanding of the growth processes of these unique nanostructures pave the way to fabrication of higher hierarchical structures embedded in thin film matrices. (C) 2016 Elsevier B.V. All rights reserved.