FABRICATION OF MELT-TEXTURED ND123 SUPERCONDUCTORS WITH ND2BAO4 ADDITION

Large melt-textured NdBa2Cu3Oy crystals with a sharp superconducting t ransition have been fabricated in air with Nd2BaO4 addition. Experimen ts show that NdBa2Cu3Oy and Nd4Ba2Cu2Oy are present in melt-textured c rystals which grow in the centre of cylindrical samples while NdBa4Cu3 Oy, as a stable phase, instead of the NdBa6Cu3Oy, phase, which has bee n reported previously, has been observed in the residual liquid phase located in the edge of samples. In comparison with the effects of Nd4B a2Cu2Oy addition, the refined Nd422 particles can be obtained in the p resent composition. The influence of the short-time thermal treatment in Ar before oxygenation has been discussed. Fabricated bulk samples e xhibit onset T-c values of 95 K and the secondary peak effect in the M -H loop. The peak values of J(c) are 2.4 x 10(4) A/cm(2) in 0 T at 77 K and 2 x 10(4) A/cm(2) in 1.3 T at 77 K. (C) 1998 Elsevier Science Lt d. All rights reserved.