Microstructure and superconducting properties of melt-processed RE-Ba-Cu-O with dispersed barium cerate particles

摘要

We studied microstructure and superconducting properties of melt-processed RE 123 (RE=Y and Dy) bulk superconductors with a large amount of BaCeO_3 addition. The melt-textured bulk samples with compositions of Y123 + xBaCeO_3 (x=0.05-0.4) and 0.5 wt% of Pt were fabricated in air. The BaCeO_3 particles with the diameter of 1-2 u.m were trapped in the melt-textured samples. The critical current density (J_c) in a low field region increased with the amount of BaCeO_3 inclusions. This suggests the BaCeO_3 particles act as effective flux pinning centers, as well as Y211 particles in conventional melt-textured Y-Ba-Cu-0 bulk materials. We found that the size of BaCeO_3 particles could be reduced by substituting Zr on Ce site. The Y123 bulk sample with 30 mol% of Ba(Ce_(0.75)Zr(0.25))O_3 and 0.5 wt% Pt showed a high J_c value of 110 kA/cm~2 at 77 K. The Dyl23 bulk samples dispersed BaCeO_3 and Ba(Ce_(0.75)Zr_(0.25))O_3 particles also exhibited excellent J_c-B properties.