Artificial Flux Pinning in MOD-REBCO Coated Conductors With Thick Superconducting Layer

The BaZrO₃ (BZO) and BaHfO₃ (BHO) nanocrystal addition strategy was extended to up-scaling YBa₂Cu₃O_7-δ (YBCO) coated conductors as long as hundreds of meters with a superconducting layer thickness of 3.2 µm. The I_c(77 K, self-field) achieved 1000 A/12 mm-width with 5 mol% BZO addition. It is revealed that the I_c(77 K, self-field) of YBCO thick tapes decreases to 700 A with BHO concentration up to 10%, while its in-field I_c enhances to 1450 A at 30 K@3 T. The transport measurement showed that the $I_c$@4.2 K at a high field as 20 T achieved 290 A/4 mm-width. The angular dependence of in-field I_c demonstrated that significant improvement occurs in almost the angular range after nanocrystal additions except B//ab. Interestingly, due to the addition of small-size nanocrystals as pinning centers, the $I_c$@77 K under the field <2 T exhibited near isotropic behaviors when applied to different magnetic field angles.