High-current Y–Ba–Cu–O superconducting films by metal organic chemical vapor deposition on flexible metal substrates

A metal organic chemical vapor deposition (MOCVD) method has been developed to achieve high currents in Y–Ba–Cu–O (YBCO) superconducting films deposited on biaxially textured buffer layers on polycrystalline (untextured) flexible metal substrates. Optimization of the MOCVD process parameters has yielded critical currents ( I c) greater than 50 A and critical current densities ( J c) higher than 1 MA/cm 2 at 77 K in self-field conditions. High values of critical currents were found to be maintained also in the presence of a magnetic field. At 75 K, with the magnetic field perpendicular to the c-axis ( B⊥ c), J c values of 570,000 A/cm 2 ( I c=20 A) and 240,000 A/cm 2 ( I c=8.5 A) were achieved in fields of 1 and 5 T respectively. With the magnetic field parallel to the c-axis ( B∥ c), J c values of 215,000 A/cm 2 ( I c=7.6 A) and 100,000 A/cm 2 ( I c=3.6 A) were achieved in fields of 1 and 2.5 T respectively. At 64 K, the J c values were 1.2 MA/cm 2 ( I c=43 A) and 770,000 A/cm 2 ( I c=27 A) at 2 and 5 T respectively in the B⊥ c orientation. In the B∥ c orientation, the J c values were 680,000 A/cm 2 ( I c=23.7 A), 520,000 A/cm 2 ( I c=18.2 A) and 300,000 A/cm 2 ( I c=10.6 A) at 1, 2, and 5 T respectively.