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 (Jc) 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, Tc, and Jc. 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. Jc rises with sintering temperature to a maximum of ∼103 A/cm2. A linear relationship between Jc and bulk density is predicted from microstructural considerations.