FABRICATION OF Y1BA2CU4O8 FILMS AND Y1BA2CU3O7-X FILMS WITH HIGHER JC BY METALORGANIC DEPOSITION

In this study, c-axis oriented Y1Ba2Cu4O8(124) films and high critical current dendity (J(c)) YBa2Cu3O7-x films were obtained by the Metalorganic Deposition (MOD) method and the MOD method with application of the decomposition process (124-->123 + CuO) respectively. C-axis oriented 124 phase films could not be fabricated from direct heat-treatment in the stable temperature region of 124. In order to obtain c-axis oriented 124 phase films, c-axis oriented 123 phase films were synthesized prior to reaction with CuO. In this process, however, single-phase films of 124 were hardly synthesized even changing the heat-treatment conditions or the ratio of CuO. First the 124 phases were synthesized, and then the high-J(c) 123 phase films were synthesized by transforming the 124 phases into the 123 phases. The reason why the high-J(c) 123 phase films were obtained is probably due to the existence of impurity phase in the 123 phase as pinning centers and/or refinement of the 123 grain boundaries.