The influence of the Ag2O addition on the thermal conductivity κ of (Nd-Eu-Gd)Ba2Cu3Oy melt-textured superconductors with several amounts of NEG-211 phase has been studied. The concentration of added Ag2O is up to 20 wt.%. The distribution of Ag was observed by back electron image. The critical current density evaluated from a magnetization measurement increases with Ag2O at higher magnetic field, which suggests the precipitation of light rare earth (LRE)-rich fine clusters. It was found that the thermal conductivity below Tc might be determined by the phonon scattering by the LRE-rich fine clusters, which suppress the enhancement of κ, and by the improvement of the crystallographic quality with Ag-doping, by which the enhancement is recovered. In almost all of the samples we measured the latter was dominant. The suppression of κ by the magnetic field H was observed below 110 K. The ratio of κ(H)/κ(H = 0) is almost independent of the amount of Ag2O content.
|Physica C: Superconductivity and its applications
|Published - 2003 10月 1
|Proceedings of the 15th International Symposium on Superconduc - Yokohama, Japan
継続期間: 2002 11月 11 → 2002 11月 13
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