Epitaxial growth of REBa2Cu3O7−y films on various substrates by chemical solution deposition

We have investigated the processing conditions for solid phase epitaxial growth of REBa2Cu3O7−y (RE=rare earth and Y; RE123) by chemical solution deposition (CSD) using metalorganic precursors. We selected two kinds of starting materials, metal naphthenates and metal trifluoroacetates, for RE123 films. The films are crystallized through barium carbonate and fluoride, respectively. Superconducting properties of RE123 films were strongly dependent on microstructure of the calcined film. In the case of the metal naphthenates route, the calcined films had to be amorphous in order to realize solid phase epitaxial growth. However, Jc of the epitaxially grown film was low. On the other hand, using the metal trifluoroacetates, RE123 films were grown epitaxially even if the calcined films were crystallized in metal oxyfluoride. To prepare thicker RE123 films, single step coating controlling concentration and/or viscosity of coating solution is necessary because F-contained reactive gas was formed during heat-treatment. Using chemically stable CeO2-buffered YSZ as substrates, we have succeeded in preparing the YBCO films, having high Jc of 3.6MA/cm2 and 4700Å in thickness.