Processing of Y₁Ba₂Cu₃O _x Films by Solution Techniques Using Metal-Organic Decomposition

Abstract

Processing of YBCO films by decomposition of metal trifluoroacetate precursors and its application to the development of coated conductors is investigated. The technique involves preparation of the solution, deposition, and a two-stage heat treatment. A stoichiometric mixture of the acetates of Y, Ba, and Cu and trifluoroacetic acid are used as the starting materials. The glassy residue of the trifluoroacetates of Y, Ba, and Cu formed by drying the above mixture is redispersed in a fixed amount of methanol to provide the starting solution of a given concentration. This solution is then deposited on the substrate surface by the spin coating technique and heat treated in two stages. X-Ray characterization shows that the transformation to 123 is complete in less than 1 h. Pole figure analysis of films deposited on (100) SrTiO₃ and LaAlO₃ single crystal substrates show that these films have a very high degreee of alignment with the substrate both out-of-plane (<0.5°) and in-plane (<1.5°). These chemically derived films were also found to have critical current densities well above 5 × 10⁵ at 77 K for 0.5 μm thick films. The applicability of this technique to the production of thick films of YBCO for the development of coated conductors will be discussed.