Summation of Flux Pinning by Columnar Defects Tilted at Different Angles in YBCO Thin Films
Summation of Flux Pinning by Columnar Defects Tilted at Different Angles in YBCO Thin Films
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YBCO 薄膜中不同角度倾斜的柱状缺陷引起的通量钉扎总和
DOI：
10.1109/tasc.2021.3059974
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发表时间：
2021
影响因子：
1.8
通讯作者：
Ishikawa Norito
中科院分区：
文献类型：
--
作者：
Sueyoshi Tetsuro;Enokihata Ryusei;Yamaguchi Hiroshi;Fujiyoshi Takanori;Okuno Yasuki;Ishikawa Norito
在77 K，1 T条件下，研究了在YBCO薄膜中添加不同角度的柱状缺陷（CD）前后临界电流密度Jc和n值的角度行为.增强的Jcat B||在θ i = ±75 °时，Jc增大，而在θi= ±85 °时，Jc减小。在θi= 0°时加入CD也降低了J循环B|| ab，初始照射角度θi= ±80°时，其强度增强。相比之下，在磁场的任何方向上，第二次照射几乎没有降低n值：n值似乎是由以不同角度倾斜的CD的钉扎相互作用的简单总和决定的。这些结果表明，在每个方向上的倾斜CD的磁通钉扎得到改善，而不会阻碍在其他CD方向上的磁通钉扎彼此。然而，额外引入的CD，诱导的超导渗流路径的减少和辐射损伤的ab-相关的PC，导致Jc的降低。
Angular behaviors of critical current density Jcand n-values at 77 K, 1 T were investigated in YBCO films with columnar defects (CDs) tilted at small angles to the ab-plane before and after the additional introduction of CDs at different angles, where CDs were installed by heavy-ion irradiations. The enhanced Jcat B || ab by the initial irradiation at θi= ±85° relative to the c-axis was reduced by the additional irradiation at θi= ±75°, whereas the Jcwas increased at the intermediate angle between the two irradiation angles. The addition of CDs at θi= 0° also lowered the Jcaround B || ab, which were enhanced by the initial irradiation angles of θi= ±80°. The n-values, by contrast, were hardly lowered in any direction of magnetic field by the second irradiation: the n-value seems to be determined by a simple sum of the pinning interactions of CDs tilted at different angles. These results suggest that the flux pinning is improved in each direction of the tilted CDs, without impeding the flux pinning in the other CD direction each other. The additional introduction of CDs, however, induces both the reduction of the superconducting percolation path and the irradiation damage to the ab-correlated PCs, resulting in the reduction of Jc.