Speaker
Description
Several present and future-relevant technologies are based on high magnetic fields provided by the superior current carrying properties of high temperature superconductors (HTS) at low temperatures. Up to 600 m long YBCO coated conductors are commercially produced. Defects, material faults and magnetic fields suppress the critical current, Ic, and determine the maximum loss-free current throughput of the tape. Manufacturing processes require efficient Ic measurement tools for reliable Ic(x) evaluation.
In this study a measurement tool (M-Scan) for continuous 4-probe Ic(x) determination at 77 K in 2.6 T flux density was developed and HTS-tapes <100 m were scanned. The measurement setup, the model to calculate Ic from the measured voltage signal and results of scanned long samples are reported. The impact of “artificial” and “natural” defects on Ic is shown and physical interpretations discussed. Comparison with an independent technique of continuous Ic evaluation via magnetic shielding shows intrinsic disagreements.
