Composition-controlled melt processing of Nd1+xBa2-xCu3O7-delta-based bulkmaterial in air

Nd1+xBa2-xCu3O7-delta (Nd-123) superconductors were melt-processed in air a tmosphere starting from an initial precursor consisting of Nd2O3, BaCuO2 an d CuO, or Nd-123 and BaCuO2, respectively, to stabilise the process to proc eed in equilibrium with compositions along the tie line Nd-123-Nd-422, both with its stoichiometric compositions. The Nd:Ba ratio was stabilised close to 1:2 and high T-c values up to 96 K were achieved. As a result, J(c) val ues of 30 kA/cm(2) (0 T) and an expressed peak effect of 10 kA/cm(2) arises at an applied external magnetic field of 2 T at 77 K. (C) 2000 Elsevier Sc ience B.V. All rights reserved.