Long-length YBCO coated stainless steel tapes with high critical currents

Progress in developing long-length YBCO coated conductors (CC) with high critical currents, up to almost 500 A per cm-width, is reported. Coated tapes based on commercial quality stainless steel substrates are manufactured employing a HR-PLD-YBCO together with an IBAD-YSZ processing route (HR-PLD: high-rate pulse laser deposition, IBAD: ion-beam assisted deposition). At 77 K in self field, critical currents up to 495 A per cm tape width were achieved in 4-10 mm wide and 5-9 m long tapes. With a 0.1 mm thick substrate tape employed for CC manufacturing, the engineering current density achieved corresponds to 494 A/mm/sup 2/. At 4.2 K and a parallel magnetic field of 23.5 T, a critical current of typically 1,350 A per cm width was observed. Study of mechanical properties of the coated tapes revealed their outstanding performance under bending and axial stress. Influence of thick shunt layers on the performance of the coated conductor was studied.