Tackling the agglomeration of Mg2Si dopant in MgB2 superconductor using cast Mg–Si alloy

Abstract The work demonstrates a method to tackle the agglomeration of Mg 2 Si dopant in chemical doping in MgB 2 superconductor to enhance its in-field critical current density. Mg-Si alloy which has uniformly distributed Mg 2 Si particles in it is prepared by casting technique. The alloy is used as the Mg source for the preparation of MgB 2 samples doped with various weight percentage of nano carbon. XRD patterns show peaks of Mg 2 Si in all Si containing samples. SEM images show a microstructure with distinctly smaller grains and reduced crystallinity in doped samples. HRTEM analysis confirms that the method led to better distribution of Mg 2 Si particles within the MgB 2 grains as compared to the normally prepared sample. It is found that doping has not severely affected the transition temperature of the samples and at the same time enhanced the in-field critical current density.