Magnetic field processing to enhance critical current densities of MgB_2 superconductors

摘要

A magnetic field of up to 12 T was applied during the sintering process of pure MgB_2 and carbon nanotube (CNT) doped MgB_2 wires. The authors have demonstrated that magnetic field processing results in grain refinement, homogeneity, and enhancement in J_c(H) and H_(irr). The extent of improvement in J_c increases with increasing field. The J_c for a 10 T field processed CNT doped sample increases by a factor of 3 at 10 K and 8 T and at 20 K and 5 T, respectively. H_(irr) for the 10 T field processed CNT doped sample reached 9 T at 20 K, which exceeded the best value of SiC doped MgB_2 at 20 K. Magnetic field processing reduces the resistivity in CNT doped MgB_2, straightens the entangled CNTs, and improves the adherence between CNTs and the MgB_2 matrix.