Comparison of YBa2Cu3O7-δ precursors made using TFA-MOD and BaF2 ex-situ processes and their post-deposition processing under low pressure conditions

Two ex-situ techniques including metal-organic deposition using solution from trifluoroacetates (TFA-MOD) and electron beam co-evaporation using BaF₂ are regarded as promising candidates for fabricating long-length, uniform, high critical current density (J_c) YBa₂Cu₃O_7-δ (YBCO) superconducting films for practical applications. It is generally accepted that the precursors made by these two methods and their post-deposition processing are basically similar. Typical MOD-TFA and e-beam BaF₂ precursors were made and then annealed in our low-pressure processing system. It was found that the conditions required for the conversion of these two types of precursors are quite different. The precursors were compared in terms of the differences in their composition and pre-conversion structure. The conversion behaviors were studied by structure characterization and property measurement. The effect of composition, especially the fluorine content on the conversion reaction is discussed.