Effect of Gd₂O₃ addition on the superconductivity of Gd-Ba-Cu-O bulk superconductor fabricated in air

Single domain bulk Gd-Ba-Cu-O superconductors 17 mm in diameter have been successfully grown by powder-melt-processing (PMP) in air. The superconducting properties of Gd-Ba-Cu-O may be improved by substituting Gd₂O₃ for Gd211 addition and the cost of preparation can be decreased. However a solid solution of Gd-Ba forms in response to the inclusion of excess Gd₂O₃, and the superconducting properties of the bulk Gd-Ba-Cu-O decrease. The addition of 0.15 mol percent of Gd₂O₃ is found to be optimal and leads to a trapped field of 0.36 T at 77 K.