Processing and properties of long-lengths of Ag-clad BSCCO superconductors and high-(Tc) magnets

摘要

Long lengths of Ag-clad mono and multicore BSCCO tapes were fabricated by the powder-in-tube technique. The critical current density (J(sub c)) of 125-m-long monocore tapes was (approx)12,000 A/cm(sup 2) (critical current, I(sub c) 20 A) at 77 K. A 230-m-long 37-filament tape carried an I(sub c) of 14 A (corresponding to a J(sub c) of (approx)10,000 A/cm(sup 2)). Pancake-shaped coils were formed from long-length conductors by the wind-and-react approach. High-T(sub c) magnets were then assembled by stacking the pancake coils and connecting them in series. The magnets were tested as a function of applied magnetic fields at 4.2, 27, 64, and 77 K. A magnet containing 480 m of high-(Tc) tape generated a record-high field of 2.6 T at 4.2 K. Another magnet assembled with (approx)770 m of tape generated a field of (approx)1 T at 4.2 K and (approx)0.6 T at 27 K, both in an applied background field of (approx)20 T. Strain tolerance of high-(Tc) tapes was evaluated by measuring J(sub c) retention as a function of applied strain in an 0.5 T applied field at 77 K.