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

Long lengths of Ag-clad mono and multicore BSCCO tapes were fabricated by the powder-in-tube technique. The critical current density (Jc) of 125-m-long monocore tapes was ∼12,000 A/cm2 (critical current, Ic 20 A) at 77 K. A 230-m-long 37-filament tape carried an Ic of 14 A (corresponding to a Jc of ∼10,000 A/cm2). Pancake-shaped coils were formed from long-length conductors by the wind-and-react approach. High-Tc 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 ∼770 m of tape generated a field of ∼1 T at 4.2 K and ∼0.6 T at 27 K, both in an applied background field of ∼20 T. Strain tolerance of high-Tc tapes was evaluated by measuring Jc retention as a function of applied strain in an 0.5 T applied field at 77 K