Effect of Prolonged IHT on BaZrO ₃ ‐Doped (Y,Gd)Ba ₂ Cu ₃ O _y Coated Conductors Fabricated by TFA‐MOD Method via Multi‐Coating

ABSTRACT We investigated the effects of a prolonged interim heat treatment (IHT) during the preparation of BaZrO 3 ‐doped (Y,Gd)Ba 2 Cu 3 O y (YGdBCO) multi‐coating films via a trifluoroacetate‐based metal organic deposition (TFA‐MOD) method. Excessively long IHT was found to lead to degradation of the critical current density ( J c ) in the films because of the presence of outer growth grains with non‐ c ‐axis orientations. Analyses by x‐ray diffraction and transmission electron microscopy showed that coarsened CuO particles were distributed in the film after the long IHT. These coarsened CuO particles induced local elemental inhomogeneity at the growing YGdBCO interface, and the growth of outer growth grains was observed throughout the film, in addition to grains epitaxially growth from the CeO 2 buffer layer.