How Moats Protect Superconductor Films From Flux Trapping
How Moats Protect Superconductor Films From Flux Trapping
复制标题
护城河如何保护超导薄膜免受通量捕获
DOI：
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发表时间：
2016
影响因子：
1.8
通讯作者：
M. M. Khapaev
中科院分区：
文献类型：
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作者：
V. Semenov;M. M. Khapaev
剩余磁场的捕获降低了超导数字电路的性能，在极端情况下，破坏了超导数字电路的可操作性。众所周知，在超导体薄膜中制造的壕沟或窄切口能够使它们免受通量捕获的影响。到目前为止，在选择这些护城河的几何形状和密度方面，直觉而不是科学发挥了更重要的作用。我们对护城河的效率进行了形式化的评估。这个过程涉及的吉布斯势的任意形状的薄膜在磁场中的计算和比较的潜力与无涡旋的薄膜和磁通冻结在护城河。我们数值模拟了在恒定剩余磁场中缓慢冷却的薄膜的吉布斯势的演化。模拟可以预测的涡和通量被困在护城河对应的最低电位的平衡分布。如果在没有珍珠涡旋的情况下可以实现最低的吉布斯势，那么超导体薄膜就会不受珍珠涡旋的影响。
Trapping of residual magnetic field degrades the performance and, in extreme cases, destroys operability of superconductor digital circuits. It is known that moats or narrow cuts made in superconductor thin films are able to “immunize” them from flux trapping. So far, an intuition rather than science has played a more significant role in the selection of geometry and density of these moats. We formalized an estimation of the moat efficiency. This procedure involves the calculation of Gibbs potentials of arbitrary shaped films in a magnetic field and comparison of the potentials with and without vortices in the film and magnetic flux frozen in the moats. We numerically simulate evolutions of the Gibbs potentials of films slowly cooled in a constant residual magnetic field. The simulations allow forecasting equilibrium distributions of vortices and fluxes trapped in the moats corresponding to the lowest potentials. The superconductor film becomes immune to the trapping Pearl vortices if the lowest Gibbs potential can be achieved without such Pearl vortices.