(Gd,Y,Er)Ba₂Cu₃O_y bulk superconducting system processed via infiltration growth

Ternary bulk REBa₂Cu₃O_y superconductors processed via oxygen-controlled melt growth (OCMG) have exhibited superior superconducting properties with respect to binary and single systems. However, the OCMG process is rather complicated, expensive, and difficult to scale-up into industrial level. To overcome these issues, we have studied the yet unexplored ternary bulk (Gd,Y,Er)Ba₂Cu₃O_y “(Gd,Y,Er)-123″ system, fabricated via trendy infiltration growth (IG) process. We studied the effect of varying Y-211 and Er-211 ratio (Gd: Y: Er = 0.33: 0.33-x: 0.33+x, where x = 0, 0.05, 0.1, 0.15 and 0.2) in the preform on the final superconducting properties and microstructure. We succeeded to fabricate (Gd,Y,Er)-123 single-grain bulks (diameter – 20 mm). The critical current density (J_c) and trapped field increased proportionally with the increased amount of Er-211 in the preform. Hall-probe measurements showed that the best bulk (x = 0.2) exhibited trapped field of 0.53 T at 77 K (applied field of 1 T) and self-field J_c values of 238 and 63 kA/cm² at 50 and 77 K, respectively. FE-SEM micrographs revealed formation of two different types of secondary phases in the matrix (small and large). EDX analysis showed that the smaller 211 particles were Er-rich, while the larger ones were an irregular mixture of three RE-211 phases.