Author: Beverstock, D.R.
Paper Title Page
MOPMB083 Investigation of the Multilayer Shielding Effect through NbTiN-AlN Coated Bulk Niobium 311
SUSPB025   use link to see paper's listing under its alternate paper code  
 
  • I.H. Senevirathne, J.R. Delayen, A.V. Gurevich
    ODU, Norfolk, Virginia, USA
  • D.R. Beverstock, J.R. Delayen, A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
  • D.R. Beverstock
    The College of William and Mary, Williamsburg, Virginia, USA
  
  We report measurements of the dc field onset Bp of magnetic flux penetration through NbTiN-AlN coating on bulk niobium using the Hall probe experimental setup. The measurements of Bp reveal the multilayer shielding effect on bulk niobium under high magnetic fields at cryogenic temperatures. We observed a significant enhancement in Bp for the NbTiN-AlN coated Nb samples as compared to bare Nb samples. The observed dependence of Bp on the coating thickness is consistent with theoretical predictions.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB083  
About • Received ※ 18 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 12 August 2023
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WEIXA01
 Experimental Evidence for Current Suppression in Superconducting Hetero Structures  
 
  • M. Asaduzzaman, T. Junginger, R.M.L. McFadden
    UVIC, Victoria, Canada
  • D.R. Beverstock, A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
  • T. Junginger, R.M.L. McFadden
    TRIUMF, Vancouver, Canada
  • T. Prokscha, Z. Salman, A. Suter
    PSI, Villigen PSI, Switzerland
  
  Coating Nb with thin layers of superconductors of higher penetration depth, than Nb have been proposed as a means of obtaining accelerating gradients (Eacc) of beyond Nb’s fundamental limit. Such heterostructures (which can also contain insulating layers between the superconductors) can potentially sustain their Meissner state above the superheating field, Bsh (of all the layers) due to the suppression of the Meissner screening current in the surface layer(s) induced by a counter-current in the substrate layer. We report evidence for counter-current flow in superconductor- superconductor (SS) Nb-Ti-N/Nb samples from depth-resolved measurements of their Meissner screening profiles at applied fields below or equal to 25 mT using the low energy muon spin rotation (LE-muSR) technique. Fits to the London model with appropriate boundary and continuity conditions determine the penetration depth of the Nb-Ti-N layers to be 182.5(31) nm in good agreement with literature values. Our results suggest that due to the strong suppression of the Meissner currents in the surface layer, multilayered structures of several superconducting and insulating layers are necessary to reach highest Eacc.
An electronic pre-print is available at https://arxiv.org/abs/2304.09360 		 
slides icon Slides WEIXA01 [0.623 MB]  
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