Flux Pinning in Superconducting YBCO Thin Films with an Artificial Magnetic Pinning Lattice

The critical current density and volume pinning force were measured to characterize the flux pinning in an YBa2Cu3O7−x (YBCO) thin films with an artificial magnetic lattice of La0.7Sr0.3MnO3 (LSMO) pinning dots. The activation energy U and critical current density Jc for the YBCO thin film with LSMO magnetic dots is increased at temperatures near Tc. The volume pinning force of the film with magnetic dots, Fp = Jc x H, can be represented as Fp x (H/Hc2)^0.5(1 - H/Hc2)^2, and suggests the existence of two-dimensional (2D) pinning behavior in measured samples. The results are discussed and compared with that of an identical YBCO film without LSMO pinning dots.