University of Greenwich, Faculty of Engineering and Science, London, SE10 9LS, United Kingdom.
University of Cambridge, Department of Engineering, Cambridge, CB3 0FA, United Kingdom.
Sci Rep. 2018 Jan 22;8(1):1342. doi: 10.1038/s41598-018-19681-8.
The extremely low decay factor on the trapped magnetic field by stacks of second-generation high-temperature superconducting tapes reported in Appl. Phys. Lett. 104, 232602 (2014), is in apparent contradiction with the classical results for the demagnetization of superconducting bulks and thin films, where the samples undergo a severe and progressive decay under crossed magnetic field conditions. Nevertheless, in this paper, we demonstrate how the theoretical approaches and experimental measurements on superconducting bulks, thin films, and stacks of superconducting tapes can be reconciled, not only under the crossed field configuration but also under rotating magnetic field conditions, by showing that the stacks of commercial tapes behave as a system of electrically unconnected layers preventing the deformation of profiles of current along its external contour. This study extends up to the consideration of using novel superconducting/ferromagnetic metastructures, where soft ferromagnetic films are interlayered, reporting a further reduction on the magnetization decay of about 50% in the crossed field configuration. Remarkably, after applying the same number of cycles either of rotating or crossed magnetic field to these metastructures, the difference between the magnetization decay is found to be negligible, what demonstrates their highly superior performance when compared to conventional stacks of superconducting tapes.
在《应用物理快报》104 卷 232602 期（2014 年）中报道的第二代高温超导带材的磁场俘获衰减因子极低，这与超导体块和薄膜的退磁经典结果明显矛盾，在这些情况下，样品在正交磁场条件下会经历严重和渐进的衰减。然而，在本文中，我们展示了如何通过表明商用超导带材的堆叠作为一个电不连接层的系统，防止电流沿其外部轮廓的形状变形，不仅在正交场配置下，而且在旋转磁场条件下，协调超导体块、薄膜和超导带材堆叠的理论方法和实验测量。这项研究扩展到了使用新型超导/铁磁亚结构的考虑，其中软铁磁薄膜被层间化，在正交场配置下报告了磁化衰减进一步降低约 50%。值得注意的是，在对这些亚结构施加相同数量的旋转或正交磁场循环后，发现磁化衰减之间的差异可以忽略不计，这表明它们与传统的超导带材堆叠相比具有更高的性能。
