Controlled introduction of flux pinning centers in YBa2Cu3O7−x films during pulsed-laser deposition

To introduce controlled random inclusion of nanometer-sized nonsuperconducting particulates in YBa2Cu3O7−x films for flux pinning enhancement, a special pulsed-laser-ablation YBa2Cu3O7−x target with a Y2BaCuO5 sector was made and the films were deposited on LaAlO3 substrates. Initial results showed that the films consist of 10–20 nm-sized precipitates. In a 0.5μm thick film, a transport critical current density (Jc)>3MA∕cm2 at 77 K in self-field was measured. Magnetization Jc at 77 and 65 K showed significant improvements in these films with fine precipitates as compared to regular YBa2Cu3O7−x films (>10 times increase at 9 T, 65 K).