Synthesis and properties of superconducting (Hg,Re)-Ba-Ca-Cu-O thick films on polycrystalline LaAlO3 substrate obtained by screen-printing method

A superconducting Hg0.7Re0.3Ba2Ca2Cu3O8+δ thick film on a polycrystalline LaAlO3 (LAO) substrate was obtained by a two-step method by screen-printing a Re0.3Ba2Ca2Cu3Ox precursor coating on the substrate followed by high-pressure gas firing in Hg vapour. Morphological observations have revealed that the adherent to the ceramic substrate film exhibited highly porous microstructure composed of plate-like crystallites characterized by a superconducting transition temperature of about 110 K. The major phases identified were a high-Tc (Hg,Re)-1223 phase and a low-Tc (Hg,Re)-1212 phase. Non-superconducting secondary impurity phases were also identified. Energy dispersion X-ray spectroscopy analyses at the substrate/film boundary showed a thin continuous layer of BaLa2O4 compound, the presence of which confirmed chemical interaction between the LAO substrate and (Hg,Re)-Ba-Ca-Cu-O film