Superconducting Properties of MgB2: Polycarbosilane Versus Conventional Nano-SiC Doping

The effect of polycarbosilane (PCS) doping on the superconducting properties of MgB₂ was systematically investigated. Highly reactive C and Si appeared after PCS decomposition facilitating incorporation of C into the MgB₂ lattice, as well as the reaction between Si and Mg, resulting in formation of a large number of small Mg₂Si particles within MgB₂ grains. C-substitution induced crystal lattice defects and impurities act as strong pinning centers, significantly improving J_c(B_a) performance in the high field region. The differences in the effects of SiC and PCS doping have been studied and are described to the structural transformation that occurs in MgB₂ after doping with these two materials.