Preparation of c-axis oriented RE123 films by metalorganic deposition process

Abstract

We have succeeded in preparing c-axis oriented REBa2Cu3O7–y (RE123; RE = Yb, Gd, Sm, Nd, La) films by metalorganic deposition process. A homogeneous coating solution having a molar ratio, RE:Ba:Cu=l:2:3, was prepared by dissolving metal naphthenates in toluene. These solutions were spin-coated onto various substrates. The precursor films calcined at 425°C were fired at various temperatures under low oxygen partial pressure condition. In the case of RE123/MgO, RE123 films crystallize from amorphous under ambient oxygen pressure and give strong (00n) peaks which correspond to c-axis orientation, however, the films were not in-plane aligned at the lower temperature region. In-plane aligned RE123 films can be obtained at the higher temperatures. On the other hand, in the case of using SrTiO3, NdGaO3 or LaA1O3 as substrate, RE123 films showed not only (00n) peaks but (n00) or (0n0) peaks which correspond to a/b-axes orientation. In-plane aligned c-axis oriented films appears at the higher temperature region.