ISOTHERMAL MELT PROCESSING OF BI-2212 THICK-FILMS

An alternative melt-processing technique has been developed for the fa brication of Bi2Sr2CaCu2Oy (Bi-2212) thick films at temperatures over 100 degrees C lower than those employed in conventional Bi-2212 melt p rocessing. Isothermal melt processing combines the melting and solidif ication steps at the same temperature [T.G. Holesinger et al., Appl. P hys. Lett. 63 (1993) 982]. This technique is possible due to the large drop in the solidus temperature with decreasing oxygen partial pressu re. High-quality thick films were processed at temperatures as low as 770 degrees C. Such films were found to be well-textured, contain rela tively few secondary phases, and possess critical current densities ov er 1 X 10(5) A/cm(2) at 4 K in self-field.