NUCLEATION OF A COMPLEX OXIDE DURING EPITAXIAL FILM GROWTH - SMBA2CU3OY ON SRTIO3

Film growth of a complex oxide is investigated during nucleation on a substrate surface. Using atomic force microscopy we have imaged subuni t cell coverage of SmBa2Cu3O7 deposited by reactive molecular beam epi taxy on a (100) SrTiO3 substrate. After a threshold deposition, c-axis islands are observed to nucleate predominantly along the surface step s. The heights of the nucleation islands are examined and a consistent layer stacking model is proposed. Cation stoichiometry of the nucleat ion islands is inferred to be dependent on the substrate surface and d ifferent from the bulk.