SUPERCONDUCTING BI-SR-CA-CU-O FILMS PREPARED BY THE LIQUID-PHASE EPITAXIAL METHOD

Bi-Sr-Ca-Cu-O superconducting films were prepared on MgO(100) single crystal substrates by the liquid phase epitaxial (LPE) method using Bi2Sr2CaCu2O(x) solution. X-ray diffraction patterns and scanning electron microscopy analysis showed the films were predominantly oriented with the c-axis perpendicular to the substrate surfaces. Two types of the growth temperature profiles, types A and B, were employed for film preparation by the LPE method. As-grown films in type A consisted of single 10 K (2201) phase. After a post-annealing, films predominantly consisted of the 80 K (2212) phase with T(c)(R = 0) = 78 K. As-grown films in type B consisted of single 80 K (2212) phase. But the films did not show a superconducting transition. The films showed a superconductivity with the highest T(c)(R = 0) = 82 K obtained by the post-annealing at 860-degrees-C for 5 h. We investigated the formation condition of the 80 K phase by controlling the temperature of the annealing process.