Enhanced superconducting properties of YBa 2 Cu 3 O 7−δ thin film with magnetic nanolayer additions

Abstract Vertically aligned nanocomposite (VAN) ( La 0.7 Sr 0.3 MnO 3 ) 0.5 (CeO 2 ) 0.5 and pure La 0.7 Sr 0.3 MnO 3 layers were incorporated into YBa 2 Cu 3 O 7−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 T c of the bilayers is about 90 K, which is close to that of pure YBCO films, while both the self-field J c sf and in-field critical current density J c in-field are largely enhanced. Among all samples, the film with VAN cap layer shows the highest J c 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.