AN ORTHORHOMBIC NDBA1.5SR0.5CU3O7-DELTA SUPERCONDUCTOR PREPARED USINGA BA1.5SR0.5CU3O5+X PRECURSOR

The Sr-substituted NdBa1.5Sr0.5Cu3O7-delta superconductor was prepared using the sol-gel derived, highly oxidized Ba1.5Sr0.5Cu3O5+x precurso r. An orthorhombic NdBa1.5Sr0.5Cu3O6.9 was obtained by the reaction be tween Nd2O3 and Ba1.5Sr0.5Cu3O5.6 at 900 degrees C under N-2 atmospher e. The superconducting transition temperatures of the sample, T-c(chi) = 85 K. T-c(onset)= 90 K and T-c(end) = 84 K, were slightly higher th an the reported values. The formation pass through this preparation me thod, the ''BCO route'', and the effects of Sr substitution on the sup erconducting properties were discussed. (C) 1997 Elsevier Science B.V.