Anomalous behavior of gold nanoislands on top of SrTiO3(0 0 1) during their overgrowth by thin YBaCuO films

Gold nanoparticles are deposited on top of atomically flat SrTiO3(0 0 1) substrates either by exploiting the self-organization of Au-loaded inverse diblock-copolymer micelles or by dewettting thin (3 nm) Au films at 700 deg. C. The resulting nanoparticles were overgrown by YBaCuO films prepared by off-axis cylindrical magnetron sputtering at 730 deg. C, the standard conditions to grow c-axis-oriented epitaxial films. In the present case, no influence of the Au particles on the structural (orientation, lattice parameter, rocking angle) or superconducting properties could be observed. Applying high resolution transmission electron microscopy, it turned out that the Au nanoparticles under the above conditions were 'lifted' by the YBaCuO film, i.e. one obtains the surprising result that the deposition of a YBaCuO film on top of Au nanoparticles on SrTiO3(0 0 1) leads to Au nanoparticles on top of the YBaCuO film immediately explaining why the overall structural and superconducting properties remain unaffected