Spatial variation of superconducting properties and compositional fluctuation in large melt-processed (Sm-Eu)123 single domains

Large size (Sm_0.5Eu_0.5)Ba₂Cu ₃O_7-δ single domains were grown in air via a hot-seeding melt process. Superconducting properties were found to gradually enhance as the grain growth proceeds, in that the grown grain displayed low T_c and J_c values at the initial crystallization in the top center of single domain while exhibiting high T_c and J _c in the edge section. The experiment unveiled that this was mainly induced by different RE-Ba substitution levels (RE=Sm and Eu). Such a spatial modulation of composition could be effectively suppressed by employing a fast cooling in the initial growth. The modified melt growth significantly improved the field trapping ability of single domain bulks.