Measurement of in-plane magnetic relaxation in RE-123 coated conductors by use of scanning Hall probe microscopy

• DOI: 10.1016/j.physc.2012.03.067
• Publication Date: 2012-04-05T11:15:40Z
• Authors: K. Shiohara; K. Higashikawa; M. Inoue; T. Kiss; Y. Iijima; T. Saitoh; M. Yoshizumi; T. Izumi
• Keywords: 0103 physical sciences; 01 natural sciences

Abstract We have investigated electric field criterion of in-plane critical current density in a coated conductor characterized by scanning Hall-probe microscopy (SHPM). From remanent field distribution and its relaxation measurements, we could obtain critical current distribution and induced electric field simultaneously by considering the Biot-Savart law and the Faraday’s law, respectively. These results lead us to evaluate a distribution of local critical current density and the corresponding criterion of electric field. As a result, it was found that the electric field criterion for the SHPM analysis was several orders lower than that used in the conventional 4-probe resistive method. However, the data point obtained by the SHPM shows good agreement with E – J curve analytically extended from the measurements by the 4-probe method. This means that we could characterize in-plane distribution of critical current density in a coated conductor at an electric field criterion quantitatively by this method in a nondestructive manner. These findings will be very important information since the uniformity of local critical current density in a coated conductor at extremely low electric fields is a key issue (1) especially for DC applications, (2) for quality control of coated conductors, and (3) for the standardization of the characterization of critical current among different methods.