Flexible stainless steel foil as a substrate for superconducting Y-Ba-Cu-O films

As-deposited superconducting Y-Ba-Cu-O films have been grown on stainless steel substrates by the plasma assisted laser deposition technique. Low interfacial diffusion of iron at the 550°C growth temperature enables us to produce superconducting films with critical temperatures up to 83 K and critical currents up to ∼4 × 103 A/cm2 (40 K). Dependence of the superconducting properties of the Y-Ba-Cu-O films on the surface condition of the mirror finished stainless steel substrate has been studied. Critical temperature and critical current of the films have been improved by heat-treating the substrate and incorporating buffer layers. Variation of the critical current with the bend radii of the film is discussed.