Effects of vortex line shape on critical current density in high Tc superconducting film with nano-rod pinning centers under applied magnetic field of various orientations

We measured magneto-optical images (MOIs) on a coated conductor comprised of (Gd,Y)1Ba2Cu3O7−δ-BaZrO3 film under applied magnetic field of various orientations. MOIs showed systematic changes of asymmetric distribution of magnetic flux density and critical current density. TEM measurements showed that nano-rod pinning centers (RPCs) tilt by ∼13° from the c-axis. We were able to explain the results of MOI measurements using a simple model calculation about vortex line shapes, which change according to the magnitude and the orientation of applied magnetic field. In this model the critical current density, which is due to the vortex pinning, is determined by the geometrical relationship of the curved vortex lines and the tilted RPCs.

► Magneto-optical imaging (MOI) is utilized to measure the magnetic properties of GdYBCO with BZO nano-rod pinning centers. ► Asymmetric characteristics of magnetic flux in oblique field were measured. ► Results from MOI experience data and model calculation about vortex line shapes are compared.