Study of tin plus cerium doping in YBCO bulk top seeded pellets

The effect of tin + cerium doping in top seeded melt textured YBCO has been studied. The compositions correspond to 0.5 wt.% CeO2 with varying tin amo unts from 0.25 to 1 wt.% in steps of 0.25 wt.%. In order to increase the bu lk pellet density, the influence of pre-sintering on each composition has a lso been investigated. In spite of a slight decrease of T-c, the best super conducting properties were obtained for the 0.25 wt.% SnO2 doped sample wit hout pre-sintering, with a critical current density reaching higher than 90 kA/cm(2) in self-field and 50 kA/cm(2) under 1 T at 77 K. Higher tin addit ions appear to damage the whole sample homogeneity and also the superconduc ting properties. The pre-sintering step, although beneficial to the pellet density, decreases the pinning under field. (C) 2000 Elsevier Science B.V. All rights reserved.