High critical current density in RE–Ba–Cu–O bulk superconductors with very fine RE₂BaCuO₅ particles

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• 作者：Nariki ; S. ; Sakai ; N. ; Murakami ; M. ; Hirabayashi ; I.
• 关键词：74.72.Bk ; 74.60.Jg ; 74.80.B ; 85.25.Ly ; Melt-textured bulk ; Critical current density ; Microstructure Gd&ndash ; Ba&ndash ; Cu&ndash ; O ; Y&ndash ; Ba&ndash ; Cu&ndash ; O
• 刊名：Physica C
• 出版年：2004
• 期刊代码：80_09214534
• 类别：ms
• 出版时间：October, 2004
• 卷：412-414
• 期：Part 1
• 页码：557-565
• 文件大小：693 K

摘要

We have studied the microstructure and critical current density (J_c) of Gd–Ba–Cu–O and Y–Ba–Cu–O bulk superconductors. The size of RE₂BaCuO₅ (RE211) particles trapped in REBa₂Cu₃O_y (RE123) matrix could be refined by employing ultra-fine RE211 powder as a precursor, which led to high J_c values exceeding 1×10⁵ A/cm² at 77 K in self-field for Gd–Ba–Cu–O. In the case of Y–Ba–Cu–O, however, the size reduction of Y211 led to inhomogeneous distribution of Y211 particles, in that the volume fraction of Y211 phase largely decreased near a seed crystal. We also studied superconducting properties of (Gd,Y)–Ba–Cu–O bulk material fabricated from precursor of Gd123-Y211. The employment of finely-milled Y211 powders resulted in a dramatic enhancement of J_c values in this system. The maximum J_c value for (Gd,Y)–Ba–Cu–O reached 2.5×10⁵ A/cm² at 77 K.