Effect of MgO nanoparticles embedded into Bi-2212/Ag tapes on the microstructure and superconducting properties

摘要

Magnesium oxide nanoparticles embedded into Bi-2212/Ag tapes may significantly improve transport properties of the tapes in magnetic fields as flux pinning centres. The effect of the addition of ultra-fine MgO particles, obtained by Mg combustion, in Bi-2212/Ag tapes was investigated in order to improve critical current densities of the tapes in magnetic fields. Optimization of the MgO concentration and uniformity of the MgO particles distribution across the tapes were also investigated. Microstructure of Bi-2212 ceramic layer and J_c of the tapes were enhanced with addition of MgO nanoparticles with concentrations of up to 4 wt.%. Higher MgO concentrations lead to degradation of the samples' microstructure and a corresponding decrease of absolute J_c values in self-field.