Development of technology for a reliable fabrication of LRE-123 materials for levitation applications above 80 K

Nanoscale secondary phase Gd₂BaCuO₅ "Gd-211" particles less than 60 nm in size, added to mixed ternary LREBa₂Cu₃O_y [LRE = (Nd_0.33Eu _0.33Gd_0.33), (Sm_0.33Eu_0.33Gd _0.33), (Nd_0.33Sm_0.33Gd_0.33)] "NEG-123, SEG-123, NSG-123" oxide powders and melt-processed in Ar-1%pO₂ gas mixture, significantly improve electromagnetic performance at low magnetic fields. As confirmed by transmission electron microscopy and dynamic force microscopy, the nanoparticles in the LRE-123 matrix not only survive the melt-texturing process but, thanks to their contamination by Zr coming from ball milling process, these particles in majority transform into a new type of even smaller defects. Further improvement in flux pinning was reached when both 123 and 211 powders were thoroughly ball milled before the melt-growth process to the similar small size. As a result, J_c values of 260 kA/cm² and 55 kA/cm² were observed in remnant state at 77 K and 90 K, respectively.