Electromagnetic properties of REBaCuO superconducting tapes considered for magnets of fusion reactors

The RE-123 tapes represent the most advanced product in the field of high temperature superconductors, developed for transport of high electric currents. Although this product has already proceeded to the stage of industrial production, the variety in techniques employed by different manufacturers make the final products by far not identical. We studied electromagnetic properties of a series of 21 tapes from main global wire manufacturers. The tapes were tested by magnetic induction technique (vibrating sample magnetometer, VSM) and by a transport current measurements. The aim was to find the best candidates for superconducting coils for fusion reactors. Engineering currents were deduced from magnetic hysteresis loops measured by VSM at 10 K, 50 K, and 77 K. The data for 77 K were compared with the results of direct transport experiments done at the same temperature. Current transport experiments also provided information on the current anisotropy. The VSM tests were repeated after neutron irradiation of the tapes by neutron fluence of 2.12 × 1018 cm−2. A significant enhancement of engineering currents was observed in magnetic fields above 0.5 T in all investigated tapes and temperatures. The enhancement, similarly as the engineering current, was roughly exponential function of temperature.