Mapping the flux penetration profile in a 2G-HTS tape at the microscopic scale: deviations from a classical critical state model
Mapping the flux penetration profile in a 2G-HTS tape at the microscopic scale: deviations from a classical critical state model
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DOI：
10.1088/1361-6668/aaf2f5
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发表时间：
2019-02-01
影响因子：
3.6
通讯作者：
Bending, Simon J.
中科院分区：
文献类型：
--
作者：
Marchiori, Estefani;Bending, Simon J.
在微观尺度上理解涡旋行为对于开发具有更大临界电流的高性能涂层导体具有极其重要的意义。在这里，我们使用扫描霍尔显微镜的两种不同的工作模式研究并绘制了不同温度下ybco基涂层导体的临界状态。对长超导带的解析Bean临界状态模型与我们的测量结果进行了比较，并用于估计临界电流密度。我们发现与模型有几个显著的偏差；由于涡束的形成，当温度降至83 K以下时，观察到明显的通量锋粗化，同时也观察到通量锋廓线的强烈拓宽。在较低温度65 K的高磁场下，局部磁化测量中观察到的鱼尾状磁化峰归因于磁锁，这是由于磁带边缘附近临界电流密度的增加而引起的，我们初步将其与涡旋钉住匹配效应联系起来。我们的测量提供了有价值的见解，丰富的涡旋现象存在于涂层导体带在微观尺度。
Understanding vortex behaviour at microscopic scales is of extreme importance for the development of higher performance coated conductors with larger critical currents. Here, we study and map the critical state in a YBCO-based coated conductor at different temperatures using two distinct operation modes of scanning Hall microscopy. An analytical Bean critical state model for long superconducting strips is compared with our measurements and used to estimate the critical current density. We find several striking deviations from the model; pronounced flux front roughening is observed as the temperature is reduced below 83 K due to vortex-bundle formation when strong broadening of the flux front profile is also seen. In higher magnetic fields at the lower temperature of 65 K, fishtail-like magnetization peaks observed in local magnetization measurements are attributed to flux-locking due to an increase in the critical current density near the edges of the tape, which we tentatively link to vortex pinning matching effects. Our measurements provide valuable insights into the rich vortex phenomena present in coated conductor tapes at the microscopic scale.