Facile preparation of large Mg-NdBCO crystal for seeding growth of high-performance YBCO single-grain superconductor

Multi-grain Mg-doped Nd–Ba–Cu–O (Mg-NdBCO) bulk was facilely prepared by employing just one precursor pellet of composition Nd1.6Ba2.3Cu3.3Ox + 1 wt% MgO. The sample exhibits typical large grains up to 15 mm in dimension, and a series of large Mg-NdBCO crystals of size 5 × 5 mm2 can be cleaved from the multi-grain sample. Single-grain Y–Ba–Cu–O (YBCO) superconductor of 16 mm in diameter has been successfully grown on the seeding of the Mg-NdBCO large crystal by the infiltration growth (IG) technique, which presents superior performances of levitation force (32.17 N) and trapped field (0.3962 T) compared with the sample grown with a small seed. As a result, by combining the large Mg-NdBCO seed with the novel IG technique we proposed, a practical method for fabricating high-performance YBCO bulk superconductors has been developed.