Microstructure and superconducting properties of top-seeded melt grown YBa₂Cu₃O₇  bulks doped with BaF₂

Abstract

The effects of fluorine on superconducting properties and microstructures of top-seeded melt grown YBa2Cu3O7−δ bulks have been investigated through BaF2 additions (up to 1 wt% BaF2). DTA measurements show that the decomposition temperature is lowered when the content of BaF2 is increased (1003 °C for the sample doped with 1 wt% BaF2). The microstructures of the doped samples are similar to those observed in fluorine-free samples. In particular, a negligible effect is observed on the size of the Y211 particles. In the same way, the superconducting properties do not change with the additions of BaF2. DTA measurements of heavily doped compositions (up to 10 wt% BaF2) show that the decomposition temperature is lowered down to 969 °C for an addition of 5 wt% BaF2. This makes BaF2 additions promising to replace silver additions in welding processes.

The Effects of BaF₂ Addition on Melt-Processed YBa₂Cu₃O_7-x Superconductors

“…Progress in Light Metals, Aerospace Materials and Superconductors fluorine is detected in the presintered sample. Delorme et al [15] think fluorine was quite homogeneously distributed in the sample and the content is too low to be detected by EDS analysis.…”