YBCO/YSZ/hastelloy superconducting tapes by IBAD magnetron deposition

Superconducting YBCO/YSZ/hastelloy tapes were fabricated by depositing epitaxial YBCO films on biaxially aligned YSZ layers on polished hastelloy substrates. YSZ buffer layers were deposited by ion beam assisted magnetron deposition. The degree of biaxial alignment in YSZ and YBCO films was determined by x-ray pole figures and φ-scans. YSZ layers of different thicknesses reveal biaxial alignment develops at a thickness as small as 100 nm and enhanced biaxial alignment was observed in homoepitaxial YSZ layers. The best YBCO films had biaxial alignment phi scan full width half maximum (FWHM) of ∼ 9°. Tapes were fabricated up to 20 cm in length with critical current density of more than 0.5 MA/cm² at 77 K in most parts of the tape. Bending measurements on 3 cm length tapes indicate it retains 80% of the critical current for bending diameter up to 20 mm.