Weakening of thickness dependence of J^sub C^ in YBa^sub 2^Cu^sub 3^O^sub 7-d^ films using a titanium-added MOD precursor solution

BaTiO3 (BTO)-doped YBa2Cu3O-δ7 (YBCO) films were prepared by the metal-organic deposition method using a precursor solution with titanium ion. These YBCO films were deposited on (00l)-oriented LaAlO3 single-crystal substrates using an automated dip coater. The thickness dependence of critical current density (JC) in the BTO-doped YBCO films was investigated. The JC value of the YBCO composite film was reduced from 6.3 to 4.6 MA/cm2 with increasing film thickness from 450 to 930 nm in self-filed at 77 K, which arose mainly from degradation of texture and roughening of the film. However, relative to undoped YBCO thick films, JC values of the YBCO composite thick films were greatly improved, and more importantly, the reduction in JC with increasing film thickness was hindered, especially in a high magnetic field. This result indicated that the introduction of BTO nanoparticles as pinning centers into YBCO matrix weakened the thickness dependence of JC.