Evaluation of Electromechanical Properties in Multiple HTS Layered Conductors at 77 K

Abstract

High engineering critical current density (J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> ) is demanded in high-performance large-scale applications such as power cables, high-magnetic-field magnets, accelerators, and fusion reactors. In developing high current capacity and low vulnerability under a high magnetic field, high-temperature superconducting (HTS) rare-earth barium copper oxide coated conductors (CCs) have undergone various trials, and CC tape characteristics have ultimately been greatly improved. The Korea Electrotechnology Research Institute recently developed a “multiple HTS layers on one substrate” (MHOS) conductor that can carry high critical current, I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> , based on the number of superconducting layers deposited on one substrate. The superconducting layers in a MHOS conductor are much thicker than in a single-layered CC tape, possibly affecting the degradation behaviors of I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> under a mechanical load. To ensure the performance and reliability of MHOS conductors, it is necessary to evaluate the strain/stress response of I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> . In this study, the electromechanical properties of MHOS conductors were investigated using the uniaxial tension test method as well as the single-sided bending test at 77 K and self-field and at 0.5 T using a pair of neodymium permanent magnets.