Effects of thickness on superconducting properties and structures of Y₂O₃/BZO-doped MOD-YBCO films

We report the thickness dependence of critical current density (J_c) in YBa₂Cu₃O_7-x (YBCO) films with BaZrO₃ (BZO) and Y₂O₃ additions grown on single crystal LaAlO₃ substrates by metalorganic deposition using trifluoroacetates (TFA-MOD). Comparing with pure YBCO films, the J_c of BZO/Y₂O₃-doped YBCO films was significantly enhanced. It was also found that with the increase of the thickness of YBCO film from 0.25 μm to 1.5 μm, the I_c of BZO/Y₂O₃-doped YBCO film increased from 130 A/cm to 250 A/cm and yet J_c of YBCO film decreased from 6.5 MA/cm² to 2.5 M A/cm². The thick BZO/Y₂O₃-doped MOD-YBCO film showed lower J_c, which is mainly attributed to the formation of a-axis grains and pores.