High flux pinning efficiency by columnar defects dispersed in three directions in YBCO thin films
High flux pinning efficiency by columnar defects dispersed in three directions in YBCO thin films
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DOI：
10.1088/0953-2048/29/10/105006
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发表时间：
2016-08
影响因子：
3.6
通讯作者：
T. Sueyoshi;T. Nishimura;T. Fujiyoshi;F. Mitsugi;T. Ikegami;N. Ishikawa
中科院分区：
文献类型：
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作者：
T. Sueyoshi;T. Nishimura;T. Fujiyoshi;F. Mitsugi;T. Ikegami;N. Ishikawa
采用重离子辐照对YBa2Cu3Oy薄膜中广泛定向分散柱状缺陷（CDs）进行了系统的通量钉钉研究：沿c轴排列的CDs平行构型，以及相对于c轴在0°和±45°交叉的CDs组成的两个三模态展布构型，其中三个辐照角定义的展布平面垂直于输运电流方向（trimodal-A）或平行于输运电流方向（trimodal- b）。在低磁场条件下，与平行结构相比，三峰结构在宽磁场取向范围内具有较高的钉钉效率。特别地，三模态- b显示了两种三模态结构中更高的临界电流密度。在±45°的三模态结构中，由于偏离c轴的倾角较大，交叉的CDs在B || c处提供了不相关的通量钉住，这有效地加强了平行于c轴的CDs的通量钉住。对于三模态B，这种辅助作用更为显著：不仅在B b| | c，而且在偏离c轴的倾斜磁场处，沿CDs的磁通线的弯曲滑动运动更有效地减少了。
A systematic investigation of flux pinning by widely direction-dispersed columnar defects (CDs) in YBa2Cu3Oy thin films was carried out by using heavy-ion irradiation: a parallel configuration of CDs aligned along the c-axis, and two trimodal splay configurations composed of CDs crossing at 0° and ± 45° relative to the c-axis, where the splay plane defined by the three irradiation angles is perpendicular (trimodal-A) or parallel (trimodal-B) to the transport current direction. The trimodal configurations show high pinning efficiency over a wide range of magnetic field orientations compared to the parallel one at low magnetic field. In particular, trimodal-B shows the higher critical current density of the two trimodal configurations. The crossed CDs at ± 45° in the trimodal configurations provide uncorrelated flux pinning at B || c due to the large tilting angle off the c-axis, which effectively reinforce the flux pinning of CDs parallel to the c-axis. This assist effect is more remarkable for trimodal-B: a kink sliding motion of flux lines along the CDs is more effectively reduced by the splay plane, not only at B || c but also at inclined magnetic fields off the c-axis.