Transmission electron microscopy study of epitaxial lanthanum-manganite thin films on SrTiO3

The microstructure of lanthanum manganite (La1-xMnO3-delta) thin film on strontium titanate (SrTiO3) substrate fabricated by liquid chemical vapour deposition has been studied by transmission electron microscopy. Both La1-xMnO3-delta and SrTiO3 have a perovskite structure with lattice misfit about 1% but there is no evidence for correlation of the density of the misfit dislocation and misfit. In the vicinity of the interface between La1-xMnO3-delta and SrTiO3, the misfit is accommodated by a distortion of the lattice of La1-xMnO3-delta. At the areas not adjacent to the interface of La1-xMnO3-delta-SrTiO3, small particles, which can be identified as MnO, are found to be associated with the misfit between La1-xMnO3-delta and SrTiO3. The MnO phase is unstable with respect to La1-xMnO3-delta. The growth of a thin film of La1-xMnO3-delta on SrTiO3 is epitaxial and an orientation relationship is (100)La1-xMnO3-delta//(100)SrTiO3//(100)(MnO) and [010]La1-xMnO3-delta//[010]SrTiO3//[010](MnO). The Interface of La1-xMnO3-delta-SrTiO3 is composed of Ti and Mn atoms plus oxygen.