X-ray investigations of epitaxial Bi2Sr2CaCu2O8+x thin films grown on SrTiO3 substrates with MgO and buffer layers for the fabrication of biepitaxial Josephson junctions

X-ray diffraction methods have been used for investigation of epitaxial Bi2Sr2CaCu2O8+x (BSCCO-2212) thin films grown by laser ablation on SrTiO3 substrates buffered with MgO and CeO2. The analysis showed that the films are nearly single crystalline. The deposition of a buffer layer improves the microstructure of the BSCCO-2212 film and leads to a light orthorhombic lattice distortion. For the film grown on a CeO2/MgO (≤10 nm) nm) buffer layer system we observed 0 deg. and 45 deg. oriented domains. Using an original method, the lattice parameters a and b were measured. It was found that the critical current Jc is closely correlated with the structural quality of the films. First experiments were carried out to prepare biepitaxial Josephson junctions based on BSCCO-2212 material. (author)