Preparation and melt processing of (RE, Y)BaCuO (RE = Nd, Sm) and (Nd, Sm)BaCuO composites

Preparation by solid state reaction shows the generation of complete solid solutions. With appropriate admixtures, the critical current density of melt processed composites is superior to that of the corresponding YBCO samples. (Nd, Y)BaCuO samples show Jc values up to 45 kA cm−2 (0 T, 77 K). The double exchange of both, Y3+ and Ba2+ , by Nd3+ or Sm3+ gives rise to the assumption that additional structural defects in this material exist which generate flux pinning centres. The 1:2:3 stochiometry in REBaCuO (RE = Nd, Sm) is stabilized by an addition of Y3+.