Enhanced flux pinning properties in superconducting YBa2Cu3O7−z films by a novel chemical doping approach

•Pure and Co-doped YBCO films were prepared by newly-developed chemical method.•The doped films have much denser and smoother surface microstructures.•Significantly enhanced fux-pinning properties have been obtained for dilute Co-doped flm.

Pure and cobalt-doped superconducting YBa2Cu3O7−z (YBCO) films were prepared on (0 0 l) LaAlO3 substrate by a newly developed polymer-assisted metal organic deposition method. The cobalt-doped YBCO films display much denser and smoother surface microstructures and the superconducting transition temperature Tc spans a small range of 1.7 K with the doping levels. Significantly enhanced flux-pinning properties have been obtained for dilute cobalt-doped film. This may be attributed to the good grain connections and the effective flux pinning centers introduced by cobalt doping.