High critical temperature superconductors have zero power consumption and could be used to produce ideal electric power lines. The principal obstacle in fabricating superconducting wires and tapes is grain boundaries—the misalignment of crystalline orientations at grain boundaries, which is unavoidable for polycrystals, largely deteriorates critical current density. Here we report that high critical temperature iron pnictide superconductors have advantages over cuprates with respect to these grain boundary issues. The transport properties through well-defined bicrystal grain boundary junctions with various misorientation angles (θGB) were systematically investigated for cobalt-doped BaFe2As2 (BaFe2As2:Co) epitaxial films fabricated on bicrystal substrates. The critical current density through bicrystal grain boundary (JcBGB) remained high (>1 MA cm−2) and nearly constant up to a critical angle θc of ∼9°, which is substantially larger than the θc of ∼5° for YBa2Cu3O7–δ. Even at θGB>θc, the decay of JcBGB was much slower than that of YBa2Cu3O7–δ.
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机译:高临界温度超导体的功耗为零,可用于生产理想的电力线。制造超导线材和带材的主要障碍是晶界-多晶体所不可避免的晶界上晶体取向的失准会大大降低临界电流密度。在这里,我们报告说,就这些晶界问题而言,高临界温度的铁氰化铁超导体比铜酸盐具有优势。系统地研究了在双晶衬底上制备的钴掺杂BaFe2As2(BaFe2As2:Co)外延膜通过定义明确的,具有不同取向角(θGB)的双晶晶界结的传输性能。通过双晶晶界的临界电流密度(Jc BGB sup>)保持较高(> 1 MA cm −2 sup>),并且在直至约9°的临界角θc时几乎保持恒定,它远大于YBa2Cu3O7–δ的〜5°的θc。即使在θGB>θc处,Jc BGB sup>的衰减也比YBa2Cu3O 7–δ sub>慢得多。
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