Ternary Nb3Sn superconductors with artificial pinning centers and high upper critical fields

Abstract

In this letter we demonstrate the development of ternary Nb3Sn multifilamentary conductors with artificial pinning centers (APC) which achieve high critical fields. These recently-developed conductors were tested in a 31 T magnet, and the results showed that their upper critical field (Bc2) values at 4.2 K are 27-28 T, and irreversible field (Birr) values are above 26 T, values similar to or higher than those of best RRP conductors. The non-Cu Jc has been brought to nearly 1200 A/mm2 at 16 T and 4.2 K, comparable to RRP, in spite of the fact that the fine-grain Nb3Sn fractions in filaments are still low (20-30%) and the grain sizes are still not fully refined (70-80 nm) due to conductor designs and heat treatments that are not yet optimized. The Nb3Sn layer Jc at 4.2 K, 16 T is 4710 A/mm2 for the APC wire with 1%Zr, about 2.5 times higher than RRP conductors, in spite of the fact that its grain size is not yet fully refined due to insufficient oxygen and unoptimized heat treatment. An analysis is presented about the non-Cu Jc that can be achieved by further optimizing the APC conductors and their heat treatments.

References in corpus (5)

• A review and prospects for Nb3Sn superconductor development
• The upper critical field of filamentary Nb3Sn conductors
• Refinement of Nb3Sn grain size by the generation of ZrO2 precipitates in Nb3Sn wires
• Internally Oxidized Nb3Sn Strands with Fine Grain Size and High Critical Current Density
• Performance Boost in Industrial Multifilamentary Nb3Sn Wires due to Radiation Induced Pinning Centers

Cited by in corpus (7)

• Ta, Ti and Hf effects on Nb${}_3$Sn high-field performance: temperature-dependent dopant occupancy and failure of Kramer extrapolation
• $\text{Ab Initio}$ Theory of the Impact from Grain Boundaries and Substitutional Defects on Superconducting Nb${}_3$Sn
• APC Nb${}_3$Sn superconductors based on internal oxidation of Nb-Ta-Hf alloys
• Achievement of FCC specification in critical current density for Nb3Sn superconductors with artificial pinning centers
• Enhancing the effective critical current density in a Nb superconducting thin film by cooling in an inhomogeneous magnetic field
• Influence of Nb Alloying on Nb Recrystallization and the Upper Critical Field of Nb3Sn
• Pressure-induced symmetry lowering in Nb3Sn1-x superconductor