Growth rate and microstructure in top-seeded melt grown Y-Ba-Cu-O bulk superconductors

摘要

The growth rate and microstructure in top-seeded melt grown Y-Ba-Cu-O crystals were compared between two kinds of polythermal sections Y_2O_3-YBa_2Cu_3O_7 and Y_2BaCuO_5-YBa_2Cu_3O_7. The Y-Ba-Cu-O single-grain crystal from a composition on the section Y_2O_3Ba_2Cu_3O_7 grew faster with planner growth front in comparision with another composition on the section Y_2BaCuO_5-YBa_2Cu_3O_7. Non-uniform segregation of Y_2BaCuO_5 particles in the matrix was observed in both crystals.