The low-temperature, high-magnetic-field critical current characteristics of Zr-added (Gd,Y)Ba _2Cu _3O _x superconducting tapes

摘要

Critical current performances of state-of-the-art Zr-added (Gd, Y)BaCuO tapes have been investigated over a temperature range of 20-77K, in magnetic fields up to 9T and over a wide angular range of magnetic field orientations. The peak in critical current that is commonly observed in the field orientation perpendicular to the tape in BaZrO _3 (BZO) containing superconducting tapes is found to vanish at 30K in magnetic fields at 1-9T. While the critical current of 15% Zr-added tapes was about 40% lower than that of 7.5% Zr-added tapes at 77 K, the pinning force values of the former were found to be 18-23% higher than those of the latter in the temperature range of 20-40K and in magnetic fields of 3-5T. The results from this study emphasize the importance of optimization of coated conductor fabrication processes for optimum performance not just in low magnetic fields at 77K but also at the operating conditions of low temperatures and high magnetic fields that are of interest, especially for rotating superconducting machinery applications.