High-speed scanning Hall-probe microscopy for two-dimensional characterization of local critical current density in long-length coated conductor

We have succeeded in significant improvement in measuring speed of scanning Hall-probe microscopy for two-dimensional characterization of local critical current density in a coated conductor. A typical measuring speed was 36 m/h with a spatial resolution of 1 mm in longitudinal direction and 40 micrometers in width direction while the combination of the speed and the resolution could be changed on demand. This was 200 times faster than the speed of our previous system, and could be applicable to a long-length conductor. From the magnetic field distribution in a remanent state, we could estimate in-plane distribution of local critical current density in nondestructive manner. For example, we could confirm almost homogeneous local properties in a GdBCO coated conductor, and at the same time we detected some defects in the edge of the conductor. Furthermore, we could also confirm the applicability of this method to a multifilamentary coated conductor. These results would be helpful for (1) quality control of an original conductor, (2) that of a finer conductor slit from a wider one, (3) that of a multifilamentary conductor, (4) understanding of macroscopic current transport properties, (5) investigating a typical statistics correlated with the fabrication process, and so on.