Shielding superconductors with thin films

Abstract

Determining the optimal arrangement of superconducting layers to withstand large amplitude AC magnetic fields is important for certain applications such as superconducting radiofrequency cavities. In this paper, we evaluate the shielding potential of the superconducting film/insulating film/superconductor (SIS') structure, a configuration that could provide benefits in screening large AC magnetic fields. After establishing that for high frequency magnetic fields, flux penetration must be avoided, the superheating field of the structure is calculated in the London limit both numerically and, for thin films, analytically. For intermediate film thicknesses and realistic material parameters we also solve numerically the Ginzburg-Landau equations. It is shown that a small enhancement of the superheating field is possible, on the order of a few percent, for the SIS' structure relative to a bulk superconductor of the film material, if the materials and thicknesses are chosen appropriately.

7 pages, 5 figures

References in corpus (3)

• Superheating field of superconductors within Ginzburg-Landau theory
• Temperature dependence of the superheating field for superconductors in the high-k London limit
• Effect of Impurities on the Superheating field of Type II superconductors

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• A New High Parallel-Field Spectrometer at TRIUMF's $\beta$-NMR Facility
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• Depth-resolved measurement of the Meissner screening profile in a niobium thin film from spin-lattice relaxation of the implanted $\beta$-emitter ${}^8$Li
• Depth-resolved Characterization of Meissner Screening Breakdown in Surface Treated Niobium
• Search for inhomogeneous Meissner screening in Nb induced by low-temperature surface treatments
• Electron-electron interactions of the multi-Cooper-pairs in the 1D limit and their role in the formation of global phase coherence in quasi-one-dimensional superconducting nanowire arrays