Composite Cu/Fe/MgB_2 superconducting wires and MgB_2/YSZ/Hastelloy coated conductors for ac and dc applications

摘要

We discuss the results of a study of MgB_2 multifilamentary conductors and coated conductors from the point of view of their future dc and ac applications. The correlation between the slope of the irreversibility line induced by neutron irradiation defects and in situ structural imperfections and the critical temperature and critical current density is discussed with respect to the conductor performance and applicability. We debate the possible origin of the observed anomalous decrease of ac susceptibility at 50 K in copper clad in situ powder-in-tube MgB_2 wires. Different conductor preparation methods and conductor architectures, and attainable critical current densities are presented. Some numerical results on critical currents, thermal stability and ac losses of future MgB_2 multifilamentary and coated conductors with magnetic cladding of their filaments are also discussed.