Additions of 0.5 wt% of rare earth oxides to TSMTG YBa2Cu3O7−δ/Y2BaCuO5 composites

Abstract The effects of 0.5 wt% RE-oxide additions on superconducting properties and microstructures of top-seeding-melt-texture-growth-processed YBa 2 Cu 3 O 7−δ ceramics have been investigated. DTA measurements show that the decomposition temperatures do not change significantly whatever the rare earth element added. The microstructures of the RE-oxides doped samples, observed by SEM, are similar to those observed in pure Y123 samples. In particular, no effect is observed on the size of the Y211 particles and no secondary phases are formed (with the possible exception of terbium doped samples). The RE-oxides doped samples require an oxygen annealing at lower temperatures compared to pure Y123 samples, suggesting that a substitution of the rare earth element for yttrium in the Y123 matrix occurs. After the proper annealing treatment, the samples doped with 0.5 wt% of Eu 2 O 3 , Lu oxide, Tb (III/IV) O, Gd 2 O 3 , or Dy 2 O 3 exhibit better critical current densities than the undoped samples, with J c values under self-field of 77 000 A cm −2 , between 25 000 and 30 000 A cm −2 for H =1 T, and J c =0 A cm −2 for H ≈3.5 T.