Microstructural and superconducting properties of C6H6 added bulk MgB2 superconductor

The effect of aromatic hydrocarbon (benzene, C6H6) addition on lattice parameters, microstructure, critical temperature (T-c), critical current density (J(c)) of bulk MgB2 has been studied. In this work only 2 mol% C6H6 addition was found to be very effective in increasing the J(c) values, while resulting in slight reduction of the T-c. J(c) values of 2 mol% C6H6 added MgB2 bulks reached to 1.83 x 106 A/cm(2) at 15 K and 0 T. Microstructural analyses suggest that J(c) enhancement is associated with the substitution of carbon with boron and which also results in the smaller MgB2 grain size. The change in the lattice parameters or the lattice disorder is claimed as a cause of the slight reduction in the T-c by carbon addition. We note that our results show the advantages of C6H6 addition include homogeneous mixing of precursor powders, avoidance of expansive nanoadditives, production of highly reactive C, and significant enhancement in J(c) of MgB2, compared to un-doped samples. (C) 2012 Elsevier By. All rights reserved.