Correlation between in-field Jc enhancement and grain connectivity in co-doped MgB2 superconductor

We report the carbon (C) substitution effects in co-doped MgB2 bulk and wire samples of Mg0.98Al0.02(B1−xCx)2 on the lattice parameters, critical temperature, resistivity, and magnetic and transport critical current density as a function of SiC doping level in the range from 0.5 wt% to 5 wt% with fixed 2 wt% alumina (Al2O3). The co-doping composition of MgB2+2 wt% Al2O3+1 wt% SiC resulted in both low and high field Jc enhancement compared to the pristine MgB2 sample due to C-substitution, small grain size, and improved grain connectivity.