Top-seeded infiltration growth of (Y, Gd)Ba₂Cu₃Oy bulk superconductors with high critical current densities

Abstract

We employed the top-seeded infiltration-growth (IG) process for the fabrication of bulk (Y, Gd)Ba2Cu3Oy (YG-123) superconductors by varying the composition of (Y, Gd)2BaCuO5 (YG-211) and compared with bulk YBa2Cu3Oy (Y-123) superconductors grown under similar conditions. IG-processed YG-123 exhibited Jc (77 K) of 4.78 × 104 A cm−2 in zero field, which was higher than the value of 3.71 × 104 A cm−2 for Y-123. The superconducting transition temperature (Tc) of YG-123 increased with increasing Gd content. However, there was spatial variation in the superconducting properties of IG-processed YG-123 samples due to the inhomogeneous distribution of YG-211. Jc values of YG-123 decreased when increasing the distance from the seed both along the a and c-axis directions. The scaling studies of the pinning behavior for YG-123 showed that non-superconducting YG-211 particles act as effective pinning centers, supported by the fact that δTc type pinning is active in the system.