Melt processing and characterization of bulk NdBaCuO

Nd1+xBa2-xCU3O7-delta (Nd123) bulk superconductors have been synthesized un der air and by the oxygen-controlled melt growth method (OCMG). We have stu died the effects of Nd4Ba2Cu2O10 (Nd422) additions, processing rates and do ping effects on the microstructure and the superconducting properties in th e OCMG-processed samples. Unlike the YBCO system, platinum doping or Nd422 additions do not refine the Nd422 secondary phase inclusions. On the other hand, Ce doping is effective in Nd422 refinement as in the YBCO system. The nucleation window has been determined for growth conditions in air, and wa s found to be in a very narrow temperature range. The effectiveness of the MgO single crystal used as seed, the occurrence of solid solution and the o xygen content are also examined. Good superconducting properties were obtai ned in OCMG samples while poor properties occurred in the air-textured samp le and cerium-doped samples.