Investigations of (Gd, Dy)BCO Bulk Superconductors Fabricated via Top-Seeded Infiltration Growth Process

Infiltration growth (IG) process is superior compared to the conventional melt growth technique and is susceptible to various parameters. In this work, we had optimized the amount of Dysprosium (Dy) in top-seeded IG processed bulk high-temperature GdBa
₂
Cu
₃
O
_7-δ
(GdBCO) superconductors for an enhancement of flux pinning. Similar sized 0, 10, 20, 30, and 40 wt% of the Dy
₂
BaCuO
₅
secondary phase particles were added in Gd
₂
BaCuO
₅
preforms, which were further subjected to top-seeded IG process in an air atmosphere. The microstructural and magnetic properties of (Gd, Dy)BCO superconducting systems were evaluated. The Dy addition shows no major influence on the microstructural features, but strongly indicates enhanced magnetic properties of final bulk (Gd, Dy)BCO composites. Sharp superconducting transitions were observed for all samples with an onset of critical temperature of ~93 K. The critical current density J
_c
of 45.5 kA/cm
²
was achieved at self-field and 77 K in optimized composition of 20 wt% Dy-added GdBCO superconductor, and a considerable J
_c
of 20 kA/cm
²
was observed at an applied magnetic field of 2 T. The enhancement in superconducting properties was ascribed to a distribution of optimized stress fields induced by lattice mismatch defects and chemical compositional fluctuations.