Speaker
Description
MgB2 is one of the practical superconductors that has been widely studied over the past two decades. The internal magnesium diffusion (IMD) method serves as a promising method because it can enhance the grain connectivity of MgB2 phase and thereby improve the superconducting current of MgB2 wires. In this work, we successfuly fabricate the km-class 30-filament MgB2 wires using the IMD method, which is strickingly the first km-class IMD MgB2 wire in the world. This indicates great potential for the application of IMD method in the future. The finished wire is ϕ1.00mm in size and the filling factor of MgB2 is around 0.10. The superconducting current Ic(4.2 K, 3 T) of our IMD MgB2 wire reaches 650 A. The highest layer-superconducting current density Jc(4.2K, 3T) is 8.9×10^5 A cm-2 and the engineering superconducting current density Je(4.2K, 3T) is 8.3×10^4 A cm-2. Meanwhile, the copper ration of our IMD MgB2 wire is around 0.28 and the RRR(300K/40K) is above 50. The high copper ration can enhance the thermal stability of low-temperature application. The flux pinning mechanism, mechanical properties, and hysteresis loss of the IMD MgB2 wire have also been studied. Finally, we are sincerely looking forward to give an oral prensention about our work in the conference.
