Influence of gas flow and improvement of homogeneity on the distribution of critical current density in YBCO coated conductor processed by TFA-MOD method

Using a scanning Hall-probe microscopy, we have investigated in-plane distribution of critical current density in TFA-MOD processed YBCO coated conductors. We compared the distributions of critical current density for two kinds of coated conductors processed with different directions of gas flow at the calcinations. As a result, it was found that the direction of the gas flow largely influenced the distribution of critical current density. For example, the maximum value of critical current density was 1.5 times higher than the average for a sample processed with a gas flow in width direction. On the other hand, the distribution of critical current density was relatively uniform for the one with a gas flow in axial direction perpendicular to the surface of the conductor. These findings will be very important information for the optimization of the manufacturer processes for the conductors. Actually, a very uniform distribution of critical current density has been observed for a coated conductor produced by an optimized process. This demonstrates a high potential of TFA-MOD processed YBCO coated conductors for practical applications.