Characterization and superconducting properties of (Sm/Y)–Ba–Cu–O composite oxides by top-seeded melt growth in air

Abstract

Large single-grain (Sm/Y) 1.8Ba 2.4Cu 3.4O y [(Sm/Y)1.8] high T c composite superconductors with/without CeO 2 addition were systematically investigated by top-seeded melt growth (TSMG) process in air atmosphere. A melt-textured Nd 1.8Ba 2.4Cu 3.4O y (Nd1.8) single crystal was used as a seed for achieving the c-axis alignment large grains perpendicular to the surface of (Sm/Y)1.8 composite oxides. The size of (Sm/Y) 2BaCuO 5 [(Sm/Y)211] nonsuperconducting inclusions of the melt-textured (Sm/Y)1.8 samples with CeO 2 addition were remarkably reduced and uniformly distributed within the (Sm/Y)Ba 2Cu 3O y [(Sm/Y)123] matrix except in the region very close to the Nd1.8 seed crystal. In both samples, (Sm/Y)1.8 and (Sm/Y)1.8 with CeO 2 addition, showed an onset T c>92 K and sharp transition.