Enhanced critical current density of MgB2 superconductor synthesized in   high magnetic fields
  The effect of high magnetic fields on the current carrying properties of both MgB2 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 MgB2 grains. As a result, the Jc of these samples has shown much higher value than that of the MgB2 samples in the absence of magnetic field. The possible mechanism of the Jc enhancement under an external magnetic field is also discussed. 
Yanwei Ma, Aixia Xu, Xianping Zhang, Xiaohang Li, S. Awaji, K.   Watanabe