Enhanced Pinning Properties of GdBa₂Cu₃O_7-δ Coated Conductors via a Post-Annealing Process

The in-field pinning properties of GdBa₂Cu₃O_7-δ (GdBCO) coated conductors (CCs) could be remarkably improved through the post-annealing process in a low oxygen pressure (PO₂). At the annealing temperature of 800 °C in a low PO₂ of 300 mtorr, the T_c,zero value of as-prepared GdBCO CCs by SuNAM Co. via reactive co-evaporation deposition and reaction (RCE-DR) was increased from 89.9 to 93.7 K after 5 min annealing, whereas it was degraded after annealing longer than 10 min. The angular dependence of critical current density J_c at 77 K in 1 and 3 T and at 65 K in 3 T revealed that GdBCO CCs post-annealed for 5 min exhibited greatly improved pinning properties along the c-axis of the GdBCO film, which is attributable to piled-up stacking faults along the c-axis of the GdBCO matrix.