Superconducting properties of Nd-Ba-Cu-O fabricated in air

摘要

We have fabricated c-axis oriented Nd-Ba-Cu-O superconductors with the top-seeded melt-growth technique in air, The highest J_c reached 50,000 A/cm~2 at 77 K and 0.9 T. The local superconducting properties strongly depended on the distance from a seed crystal. The onset T_c as well as the transition width was improved as the distance from a seed increased. The chemical analyses revealed that the substitution levels of Nd on the Ba site gradually decreased with increasing the distance from a seed.