STRUCTURAL CHARACTERIZATION OF EPITAXIAL BISRCACUO FILMS ON MGO SUBSTRATES

We have studied the epitaxial growth of thin Bi2Sr2Ca1Cu2O8 films on ( 001) oriented MgO substrates. These films were grown using the in-situ laser ablation process (700 degrees C, 0.1 mbar oxygen), and they sho wed a perfect c-axis alignment normal to the substrate, characterised by narrow mosaic distributions and by channeling effects (low chi(min) values) along this direction. Despite the large difference between th eir lattice parameters (9%), the epitaxial growth of the BiSrCaCuO fil m on MgO substrate has been found evidence for using X-ray diffraction in transmission geometry, by the observation of three azimuthal adjus tments of the a- and b-axes of the films with respect to the a-axis of the substrate (0 degrees, 13 degrees and 45 degrees). The possible or igins of such epitaxial relationships are presented and discussed.