Strong c-axis correlated pinning and hybrid pinning in YBa₂Cu₃O_7-δ films containing BaHfO₃ nanorods and stacking faults

High critical current density (J_c) was achieved in low temperatures of 40 and 20 K in YBa₂Cu₃O_7-δ films containing elongated BaHfO₃ nanorods and stacking faults, which were prepared using pulsed laser deposition and post-oxygen-annealing. The YBa₂Cu₃O_7-δ + BaHfO₃ film exhibited global pinning force maximum (F_p,max) of 312 GNm^-3 at 40 K and 619 GNm^-3 at 20 K due to strong pinning by nanorods. These Fp,max values are comparable to those in the previously-reported high-J_c films with almost the same matching field. Thus, the present study demonstrated that YBa₂Cu₃O_7-δ superconducting matrix realized high J_c in low temperatures like other REBa₂Cu₃O_7-δ (RE = Gd, Sm, (Gd, Y)). Furthermore, high J_c was obtained also for magnetic field parallel to the ab-plane, indicating hybrid pinning of nanorods and stacking faults. Thus, the stacking faults significantly affected the J_c properties in the YBa₂Cu₃O_7-δ films containing nanorods.The present film structure with strong c-axis correlated pinning and hybrid pinning is effective in simultaneous control of J_c values and J_c anisotropy in YBa₂Cu₃O_7-δ films.