Effect of BaCeO3 addition on the microstructure and current density of melt-processed Y1.5Ba2Cu3Ox superconductors

The effect of BaCeO3 addition (0–45 wt%) on the microstructure and critical current density of melt-processed, Y2BaCuO5 (Y211) excessive Y1.5Ba2Cu3Ox (Y1.5) superconductors was investigated. The BaCeO3 powder was synthesized by the conventional powder calcination method involving powder weighing, mixing and repeated firing process. The prepared BaCeO3 powders with various compositions were mixed with Y1.5Ba2Cu3Ox powder, made compacts and finally melt-processed with top seeding. It was found that the size of Y211 particles inside YBa2Cu3O7−y (Y123) was linearly reduced as the amount of BaCeO3 increased. In addition, fine BaCeO3 particles are distributed with Y211 particles in Y123 matrix, but were agglomerated at much BaCeO3 addition of 45 wt%. The current density (Jc) increased as a weight fraction of BaCeO3 increased and it reached to maximum at 35 wt% BaCeO3. The Jc variation by BaCeO3 addition was explained in terms of the BaCeO3 and Y211 distribution in a Y123 matrix.