Magnetic field processing to enhance critical current densities of MgB2 superconductors

摘要

Magnetic field of up to 12 T was applied during the sintering process of pureMgB2 and carbon nanotube (CNT) doped MgB2 wires. We have demonstrated thatmagnetic field processing results in grain refinement, homogeneity andsignificant enhancement in Jc(H) and Hirr. The Jc of pure MgB2 wire increasedby up to a factor of 3 to 4 and CNT doped MgB2 by up to an order of magnitudein high field region respectively, compared to that of the non-field processedsamples. Hirr for CNT doped sample reached 7.7 T at 20 K. Magnetic fieldprocessing reduces the resistivity in CNT doped MgB2, straightens the entangledCNT and improves the adherence between CNTs and MgB2 matrix. No crystallinealignment of MgB2 was observed. This method can be easily scalable for acontinuous production and represents a new milestone in the development of MgB2superconductors and related systems.