This work reports the longitudinal thermal conductivity, κ, of Ag- and Cu/Ag-sheathed Ba1-xKxFe2As2 conductors. Our investigation has been carried out between 4 K and 80 K with magnetic fields up to 19 T. In the case of Ag-sheathed tapes, the thermal conductivity reaches maximum values of ∼80 Wm−1K−1 and is weakly dependent on the field. The use of Cu/Ag in the place of Ag allows increasing κ up to ∼250 Wm−1K−1. Zero-field κ values are about one order of magnitude lower than those achieved in other technical superconductors that employ a silver matrix, as Bi2Sr2CaCu2O8+x (Bi2212) and Bi2−xPbxSr2Ca2Cu3O10−x (Bi2223). This is a consequence of the contamination of the metal sheaths because of elemental diffusion occurring during the tape sintering. The differences in κ between the Ba1-xKxFe2As2 tapes and the other technical superconductors with an Ag matrix become smaller at high field. We suggest that performing the sintering at high pressure could represent a way to reduce the elemental contamination and thus improving the thermal conductivity.

中文翻译：

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Ag 和 Cu/Ag Ba1-xKxFe2As2 复合导体的现场热导率


这项工作报告了 Ag 和 Cu/Ag 护套 Ba1-xKxFe2As2 导体的纵向导热系数 κ。我们的研究在 4 K 到 80 K 之间进行，磁场高达 19 T。对于 Ag 护套胶带，热导率达到最大值 ∼80 Wm−1K−1，并且与磁场的关系很弱。使用 Cu/Ag 代替 Ag 可以将 κ 增加至~250 Wm−1K−1。零场 κ 值比采用银基体的其他技术超导体（如 Bi2Sr2CaCu2O8+x (Bi2212) 和 Bi2−xPbxSr2Ca2Cu3O10−x (Bi2223)）低大约一个数量级。这是由于带材烧结过程中发生元素扩散而导致金属护套污染的结果。 Ba1-xKxFe2As2 带和其他具有 Ag 基体的技术超导体之间的 κ 差异在高场下变得更小。我们建议在高压下进行烧结可能是减少元素污染从而提高导热性的一种方法。