Enhanced superconducting properties of YBa2Cu3O7−δ thin film with magnetic nanolayer additions

Vertically aligned nanocomposite (VAN) (La0.7Sr0.3MnO3)0.5(CeO2)0.5 and pure La0.7Sr0.3MnO3 layers were incorporated into YBa2Cu3O7−δ (YBCO) thin films as bilayer stacks for magnetic flux pinning enhancement. The films show high epitaxial quality, suggested by XRD and TEM study. The critical temperature Tc of the bilayers is about 90 K, which is close to that of pure YBCO films, while both the self-field Jcsf and in-field critical current density Jcin-field are largely enhanced. Among all samples, the film with VAN cap layer shows the highest Jc values in all field ranges. This study demonstrates an effective way towards the tunable pinning effect for YBCO coated conductors by both defect and magnetic pinning.