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This content will become publicly available on November 28, 2018

Title: An intermetallic powder-in-tube approach to increased flux-pinning in Nb 3Sn by internal oxidation of Zr

We report on the development of multifilamentary Nb 3Sn superconductors by a versatile powder-in-tube technique (PIT) that demonstrates a simple pathway to a strand with a higher density of flux-pinning sites that has the potential to increase critical current density beyond present levels. The approach uses internal oxidation of Zr-alloyed Nb tubes to produce Zr oxide particles within the Nb 3Sn layer that act as a dispersion of artificial pinning centres (APCs). In this design, SnO 2 powder is mixed with Cu 5Sn 4 powder within the PIT core that supplies the Sn for the A15 reaction with Nb1Zr filament tubes. Initial results show an average grain size of ~38 nm in the A15 layer, compared to the 90–130 nm of typical APC-free high-J c strands made by conventional PIT or Internal Sn processing. Furthermore, there is a shift in the peak of the pinning force curve from H/H irr of ~0.2 to ~0.3 and the pinning force curves can be deconvoluted into grain boundary and point-pinning components, the point-pinning contribution dominating for the APC Nb-1wt%Zr strands.
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  1. Formerly SupraMagnetics Inc., Plantsville, CT (United States)
  2. Florida State Univ., Tallahassee, FL (United States)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Superconductor Science and Technology
Additional Journal Information:
Journal Volume: 31; Journal Issue: 1; Journal ID: ISSN 0953-2048
IOP Publishing
Research Org:
Florida State Univ., Tallahassee, FL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; 43 PARTICLE ACCELERATORS; Nb3Sn; superconductors; powder-in-tube technique; PIT; flux-pinning; critical current density; artificial pinning centers; APC; Nb1Zr; microstructure
OSTI Identifier: