Evaluation of the Electromechanical Performance of Practical REBCO CC Tapes Under Low Magnetic Fields Using a Continuous Critical Current Measuring System at 77 K

The superior electromechanical properties (EMPs) of REBCO coated conductor (CC) tapes allow their use in a wide range of practical superconducting applications such as coils and magnets; however, the extreme environments degrade the current-carrying capabilities of the tapes. It is therefore important to develop techniques for evaluating their EMPs, to determine their design limits, and to assess the strain/stress dependence of critical current, I-c, in various settings. Moreover, understanding the I-c degradation behaviors of CC tapes under low magnetic fields will provide information helpful for predicting I-c behaviors when the operating conditions include high magnetic fields and low temperatures. Therefore, in this study, the EMPs of three kinds of practical REBCO CC tapes under low magnetic fields were evaluated using our recently developed easy-to-use measuring system that can continuously measure variations in I-c while applying a load or deformation to a CC tape specimen. Through the feedback control of voltage induced across the specimen during loading, we could depict the I-c degradation behaviors of the CC tapes.