Improved flux pinning in YBa2Cu3O7 with nanorods of the double perovskite Ba2YNbO6

We report significantly enhanced critical current densities (Jc) and flux pinning forces (Fp) in applied magnetic fields for YBa2Cu3O7 (YBCO) films with embedded Ba2YNbO6 (BYNO) nanorods. The films were grown by pulsed laser deposition with a target consisting of YBa2Cu3Oy with five molar per cent additions of BaNbOy and Y2O3. With this composition, deposited films were found to contain a high density of BYNO nanorods that frequently traversed the entire thickness of the film (up to 1? ?m), depending upon the deposition conditions. Enhanced Jc performance occurs primarily for applied field orientations near the c-axis of the YBCO, which is nominally along the growth direction of the BYNO nanorods. The threading nanorod density of one film of the present work was measured by plan-view transmission electron microscopy to be 710?850 nanorods??m ? 2. For approximately 1??m thick films, typical Jc(75.6?K, sf) and values were ~ 4.5?MA?cm ? 2 and 1.3?1.5?MA?cm ? 2, respectively. For a 0.5??m thick film, was achieved, and values of Fp in excess of 30 and 120?GN?m ? 3 were achieved at 75.5?K and 65?K, respectively.