摘要：We report microstructural design via control of BaZrO3 (BZO) defect density in high temperature superconducting (HTS) wires based on epitaxial YBa2Cu3O7-δ (YBCO) films to achieve the highest critical current density, J c, at different fields, H . We find the occurrence of J c( H ) cross-over between the films with 1–4 vol% BZO, indicating that optimal BZO doping is strongly field-dependent. The matching fields, Bφ, estimated by the number density of BZO nanocolumns are matched to the field ranges for which 1–4 vol% BZO-doped films exhibit the highest J c( H ). With incorporation of BZO defects with the controlled density, we fabricate 4-μm-thick single layer, YBCO + BZO nanocomposite film having the critical current ( I c) of ~1000 A cm−1 at 77 K, self-field and the record minimum I c, I c(min), of 455 A cm−1 at 65 K and 3 T for all field angles. This I c(min) is the largest value ever reported from HTS films fabricated on metallic templates.
