Barium cerate as effective flux pinning centers in Y123 bulk materials

Bulk superconductors with compositions of YBa(2)Cu(3)Oy + xBaCeO(3) (x = 0.05-0.5) and 0.5 wt.% Pt were fabricated by melt processing in air. BaCeO3 particles of 1-2 mu m diameter were dispersed in the Y123 matrix, and critical current density (J(c)) increased with the amount of BaCeO3 for the sample with x = 0.05-0.3. We also found that the size of BaCeO3 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, where the Ba(Ce, Zr)O-3 inclusions were reduced to less than 1 pin in size. However, excess substitution of Zr led to inhomogeneous distribution of the additives and lowered J(c) values. (c) 2005 Elsevier B.V. All rights reserved.