Excess Mg addition MgB2 /Fe wires with enhanced critical current density

MgB2 /Fe wires with 10 at. % excess Mg produced by in situ powder-in-tube processing were

compared to normal stoichiometric MgB2 /Fe wires prepared by the same method. It was found that

the critical current density Jc and the irreversibility field Hirr were significantly enhanced for

MgB2 /Fe wires with excess Mg. The transport Jc for 10 at. % Mg excess samples sintered at

800 °C, measured at a field of up to 14 T, increased by a factor of 2 compared to that for the normal

MgB2 wires. The best Jc results for the 10 at. % Mg excess sample were obtained by heating the

sample at 600 °C for 1 h; the Jc at a field of 8 T and at temperature of 10 K reached 3

104 A/cm2. The detailed analysis of the effect of excess Mg on the microstructures, the Jc, and

the Hirr, of MgB2 /Fe wires are presented in this paper.