High Critical Current Density of Nanostructured MgB2 Bulk Superconductor Densified by Spark Plasma Sintering

In situ MgB2 superconducting samples were prepared by using the spark plasma sintering method. The density of the obtained bulks was up to 95% of the theoretical value predicted for the material. The structural and microstructural characterizations of the samples were investigated using X-ray diffraction and SEM and correlated to their superconducting properties, in particular their critical current densities, J(c), which was measured at 20 K. Extremely high critical current densities of up to 6.75 x 10(5) A/cm(2) in the self-field and above 10(4) A/cm(2) at 4 T were measured at 20 K, indicating that vortex pinning is very strong. This property is mainly attributed to the sample density and MgB2 nanograins in connection to the presence of MgO precipitates and areas rich in boron.

Automated summary

In this study, in situ MgB2 superconducting samples were prepared using the spark plasma sintering method. The samples exhibited high critical current densities and strong vortex pinning ability, which can be attributed to the sample density and the presence of MgB2 nanograins in connection to MgO precipitates and areas rich in boron.