A Method for Inspecting Local Degradation in High-Current HTS Conductors Comprised of Stacked REBCO Tapes via Rotational Magnetization Measurement

The structure of high-current-capacity high-temperature superconductor (HTS) conductors primarily comprise stacked REBCO tapes. During fabrication, degradation in critical current values has been observed. Although defect detection methods for individual REBCO tapes are well-established, equivalent methods for complete conductors remain under development. In this study, we utilized a rotational magnetization measurement technique to locate degradation within stacked REBCO tapes. To validate the principle of defect detection using this approach, we measured the magnetization of samples consisting of 10 layers of stacked REBCO tapes. The measurement yielded a magnetization signal with two peak values per rotation, demonstrating the potential for detailed defect analysis. Additionally, variations in the intensity and waveform of the magnetization signal were observed, correlating with the position of degraded REBCO tapes. These findings indicate that magnetization signal analysis can effectively pinpoint defect locations. The reliability of the magnetization signal was further corroborated through finite element method analysis.