Effective Measuring Position of Hall Probe and <tex-math notation='LaTeX'>$j_\mathrm{c}$</tex-math> Characterization of Rectangular HTS Thin Films

Scanning Hall probe (SHP) system is a powerful instrument to investigate the planar distribution of areal critical current density (j c ) and defects of high temperature superconducting (HTS) thin film samples. The distance between the effective measuring position and probe bottom (h 1 ) is usually unknown for the commercialized Hall probes. However, h 1 value has a significant influence on the measurement results, according to the calculation of the magnetic flux density (B 0 ) above the planar center of a rectangular HTS thin film sample. In this paper, a method was proposed to obtain h 1 by using a series of copper strips and analyzing the relationship of B 0 against the parameters, such as sample width and current. Then, SHP system was employed to characterize the j c distribution of an HTS thin film fabricated via chemical solution deposition. The relationship of B 0 and h 1 could also be utilized to obtain the average j c value (j c B0 ). A series of commercialized coated conductor samples were measured with both SHP and the traditional four-probe method. The feasibility of preliminary evaluation for rectangular HTS thin film samples by using j c B0 was discussed based on its correlation with the results of four-probe method.