Large-area HTS-coated stainless steel tapes with high critical currents

Recent progress is reported in developing large-area HTS-coated stainless steel (SS) tapes. A new type of Cr-Ni SS exhibiting a high temperature resistance against oxygenation was employed as a substrate material. These SS tapes exhibit a favourable mechanical performance and allow a cost-efficient production. YBCO films have been grown on IBAD-YSZ buffered 0.1 mm-thick SS foils using a newly developed High-Rate Pulsed-Laser-Deposition (HR-PLD) technique which allows an increase of the film deposition rate by at least a factor of 20 compared to conventional PLD. The HR-PLD increases drastically the integral deposition rate to >35 nm m²/h keeping the “local” repetition rate of the deposition pulses at lower values of <20 Hz. For the shorter coated tapes (110×10 mm² ) critical current densities, J_c´s, up to 23 kA/mm² were observed at 77 K. Long coated SS tapes with J_c of (4-6) kA/mm² were manufactured in dimensions up to 1 m×34 mm. HTS properties of the coated tapes are studied and discussed