It is important to understand AC properties of coated conductor for commercialize and other applications. In recent studies, we measured DC transport current distribution in coated conductor with various external magnetic fields and noticed that the DC current distribution was redistributed by external fields. Along the DC current experiment, investigation about difference between DC and AC current distribution and field dependence of AC current had being necessary. In this study, we developed the technique which can detect selectively signal of AC transport current in noise-free condition by using Low Temperature Scanning Hall Probe Microscopy (LTSHPM) and Lock-in amplifier. We applied AC transport current to GdBCO coated conductor samples in near Tc (T/Tc = 0.909) and measured 1-dimensional magnetic field distribution. We obtained distribution of AC current by inversion calculation from magnetic field distribution and compared with distribution of DC current. We carried out same measurements at various external DC magnetic fields and investigated field dependence of AC current distribution.
Thesis Advisor: Prof. Hyeong-Cheol Ri