Superconducting properties of Gd123 superconductor fabricated in air

Single-grain bulk Gd-Ba-Cu-O superconductors 32 mm in diameter have successfully been grown by melt-processing in air. In contrast to Sm123 and Nd123, the superconducting properties of Gd123 bulk superconductors were not degraded even when they were fabricated in air, which is attributed to the small range of Gd-Ba solid solution. The sample with the chemical composition of Ba-rich Gd123 (Gd0.95Ba2.05Cu3Oy) was also fabricated in air and exhibited superconducting properties superior to those of the sample with the stoichiometric ratio.