Probing the effect of interface on vortex pinning efficiency of one-dimensional BaZrO3 and BaHfO3 artificial pinning centers in YBa2Cu3O7-x thin films

C-axis-aligned one-dimensional artificial pinning centers (1D-APCs) provide strong correlated pinning of magnetic vortices and enhance critical current density Jc in superconducting YBa2Cu3O7-x (YBCO) films and coated conductors. A fundamental question arises on what determines the pinning efficiency of different 1D-APCs. To shed light on this question, this work investigates the correlation between the 1D-APC/YBCO interface and the pinning efficiency of 1D-APCs of BaHfO3 (BHO) and BaZrO3 (BZO) of comparable diameters of 5-6 nm. Intriguingly, a highly coherent BHO 1D-APC/YBCO interface is revealed even at a high BHO doping level of 6 vol. %, in contrast to a semi-coherent BZO 1D-APC/YBCO interface with a large number of dislocations. This leads to a profound effect on the pinning efficiency of these 1D-APCs. Specifically, a record high pinning force density peak F-p,F-max similar to 182.0 GN m(-3) at H-max > 9.0 T and 65 K is obtained in the former, which is 2.5 times of the best reported in the latter. Moreover, a ratio of H-max to accommodation field H* determined from the 1D-APC areal concentration is found up to 3.5 in the former in contrast to 0.7 in the latter, demonstrating the critical impact of the APC/YBCO interface on the pinning efficiency of 1D-APCs. Published by AIP Publishing.