Mechanisms for enhanced supercurrent across meandered grain boundaries in high-temperature superconductors
Mechanisms for enhanced supercurrent across meandered grain boundaries in high-temperature superconductors
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DOI：
10.1063/1.2800255
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发表时间：
2007-10-15
影响因子：
3.2
通讯作者：
Larbalestier, D. C.
中科院分区：
文献类型：
--
作者：
Feldmann, D. M.;Holesinger, T. G.;Larbalestier, D. C.
众所周知，高温超导体中晶界 (GB) 上的临界电流密度 J(c) 随着取向差角 θ 超过 2 度至 3 度而呈指数下降。这种快速下降是由于晶界处超导有序参数受到抑制，从而产生了弱钉扎的阿布里科索夫-约瑟夫森 (AJ) 涡旋。在这里，我们表明，如果 GB 平面蜿蜒，这种指数依赖性不再成立，从而允许大大提高 Jc 值：在 0 T 时最多可达 6 倍，在 1 T 时最多可达 4 倍，θ 类似于 4 度 - 6 度。这种增强是由于晶界载流横截面的增加以及晶界平面中短 AJ 涡旋段的出现，受到与晶粒中强钉扎 Abrikosov (A) 涡旋相互作用的限制。 (C) 2007 年美国物理研究所。
It has been well established that the critical current density J(c) across grain boundaries (GBs) in high-temperature superconductors decreases exponentially with misorientation angle theta beyond similar to 2 degrees-3 degrees. This rapid decrease is due to a suppression of the superconducting order parameter at the grain boundary, giving rise to weakly pinned Abrikosov-Josephson (AJ) vortices. Here we show that if the GB plane meanders, this exponential dependence no longer holds, permitting greatly enhanced Jc values: up to six times at 0 T and four times at 1 T at theta similar to 4 degrees-6 degrees. This enhancement is due to an increase in the current-carrying cross section of the GBs and the appearance of short AJ vortex segments in the GB plane, confined by the interaction with strongly pinned Abrikosov (A) vortices in the grains. (C) 2007 American Institute of Physics.