Critical Current Densities in Thin Ceramic Tapes of Superconducting Ba2YCu3O7

Tape-cast slurries of Ba₂YCu₃O₇ powders offer a convenient means of preparing sintered ceramic samples for critical current density (J_c) measurements where the transport cross section is small and the current electrode areas are large. Samples were sintered from 900° to 1000°C and characterized for bulk density, grain size, phase composition, T_c, and J_c. Bulk density and grain size both increase with sintering temperature while all samples were single-phase perovskite except for those sintered at 900°C. The onset temperature for superconductivity is constant at about 93 K while the transition sharpens to R=0 at about 92 K for the densest samples. J_c rises with sintering temperature to a maximum of ∼10³ A/cm². A linear relationship between J_c and bulk density is predicted from microstructural considerations.