Enhanced Critical Current Density of MgB_2 Superconductor Synthesized in High Magnetic Fields

摘要

The effect of high magnetic fields on the current carrying properties of magnesium diboride (MgB_2) bulks and Fe-sheathed tapes was investigated following different thermal sequences. It is found that application of a large magnetic field during processing results in the quite uniform microstructure and the better connectivity between the MgB_2 grains. As a result, the J_c of these samples has shown much higher value than that of the MgB_2 samples in the absence of magnetic field. The possible mechanism of the J_c enhancement under an external magnetic field is also discussed.