Critical current density in MgB2 bulk samples after co-doping with nano-SiC and poly zinc acrylate complexes

The co-doped MgB2 bulk samples have been synthesized using an in situ reaction processing. The additives is 8 wt.% SiC nano powders and 10 wt.% [(CH2CHCOO)2Zn]n poly zinc acrylate complexes (PZA). A systematic study was performed on samples doped with SiC or PZA and samples co-doped with both of them. The effects of doping and co-doping on phase formation, microstructure, and the variation of lattice parameters were studied. The amount of substituted carbon, the critical temperature (Tc) and the critical current density (Jc) were determined. The calculated lattice parameters show the decrease of the a-axis, while no obvious change was detected for c-axis parameter in co-doped samples. This indicates that the carbon was substituted by boron in MgB2. The amount of substituted carbon for the co-doped sample shows an enhancement compared to that of the both single doped samples. The co-doped samples perform the highest Jc values, which reaches 3.3 × 104 A/cm2 at 5 K and 7 T. It is shown that co-doping with SiC and organic compound is an effective way to further improve the superconducting properties of MgB2.

► SiC and poly zinc acrylate complexes co-doped MgB2 bulk has been synthesized.
► Co-doping can cause higher carbon substitutions and the second phase particles.
► Co-doping can further increase the Jc value of MgB2 bulk on the base of the SiC doping.