Bend strain tolerance of YBa2Cu3O7−x-coated conductors fabricated by inclined substrate deposition

The effect of tensile bend strain on the critical current of YBa 2 Cu 3 O 7− x (YBCO)-coated conductors was evaluated as a function of YBCO film thickness. The YBCO-coated conductors were fabricated on Hastelloy C276 metal substrates templated with MgO by inclined substrate deposition. It was observed that a conductor with 0.2 µm thick YBCO retained 90% of the unstrained critical current until a strain of ≈0.4%, whereas for a conductor with 0.5 µm thick YBCO film the critical strain value was ≈0.2%. At strains higher than the critical strain, the critical current dropped precipitously. The inverse dependence of bend strain tolerance on the YBCO film thickness is in reasonable agreement with analytical prediction. This inverse dependence was used to approximate the fracture toughness of the YBCO film, which was found to be in general agreement with the literature.