The Post-Annealing Effect on the Pinning Properties of GdBa2Cu3O 7−δ Coated Conductors via RCE-DR

We report the post-annealing effect on the pinning properties of GdBa
₂
Cu
₃
O
_7-δ
(GdBCO) coated conductors (CCs) fabricated by a reactive co-evaporation deposition and reaction process. The GdBCO CCs annealed at 750 °C in the PO
₂
of 300 mtorr for 15 min show the most enhanced critical current densities (J
_c
) for B//c due to the stacking faults (SF) piled up along the c-axis. The minimum J
_c
values of post-annealed samples in relatively higher fields such as 5 T at 77 K and 7 T at 65 K were larger than those of pristine sample; although their minimum J
_c
values were lower in relatively lower fields such as 1 T at 77 K and 3 T at 65 K. In-field J
_c
values for B//ab were closely related to the density of SFs within samples. Analysis results by transmission electron microscopy revealed that the SF density was remarkably reduced after the post-annealing process, which is responsible for enhanced minimum J
_c
values and significantly degraded J
_c
values for B//ab in relatively higher fields.