High magnetic field properties of critical current density in Y ₁Ba₂Cu₃O_7-δ coated conductor fabricated by improved TFA-MOD process

Current transport characteristics in a Y₁Ba₂Cu ₃O_7-δ (YBCO) coated conductor fabricated by a trifluoroacetates-metal organic deposition (TFA-MOD) process were investigated over a wide range of temperature and magnetic field up to 25 T. Improved TFA-MOD process was successfully introduced for the better property of critical current density, J_c, at high magnetic fields. The J_c and critical current, I_c, values of multi-coated film with 1.2 μm thickness and 1 cm width were 2.1 MA/cm² and 251 A at 77 K in self-field. Additionally, the superior J_c properties remained even at high magnetic fields over 20 T and lower temperature, e.g. J_c value at 30 K in 25 T was 1.0 MA/cm². The J_c value was about 2.5 times higher than those of previous TFA-MOD process at wide range of magnetic field. Moreover, the statistical distribution of J_c in the conductor was also estimated within a framework of the percolation model. The uniformity in the YBCO coated conductor was improved by optimizing the TFA-MOD process.