Percolation behaviour in intergrowth BiSrCaCuO structures grown by molecular beam epitaxy

BiSrCaCuO thin films and specially Bi-2212 compounds were grown on (100) Sr TiO3 substrates by molecular beam epitaxy (MBE). The growth mechanism was c ontrolled in real time by monitoring the RHEED intensity. The deposition se quence of the elements was also varied in order to induce intergrowth struc tures at nanometer scale. The resulting high density of stacking faults is in contrast with a very low roughness (in the range of 1 nm as measured by atomic force microscopy), a strong c-axis texturation, and a full epitaxy w ithin the ab-plane as confirmed by four circle X-ray diffraction. The local structure of the films was examined by high resolution transmission electr on microscopy (HRTEM) in correlation with the superconducting properties. B oth structural and transport properties seem to be deeply affected by the p ercolation of 2212 domains as their concentration in the film is changed. ( C) 2000 Elsevier Science B.V. All rights reserved.