Influence of Nanostructural Inhomogeneities on Superconducting Characteristics of MgB2

The distribution of nanostructural inhomogeneities, such as areas with high concentration of B and impurity O, plays one of the key roles on the variation of the critical current density, j c, of MgB2 materials. The effect of O and B redistribution can be enhanced by Ti addition and thus leads to the j c increase. The effect of Ti addition and the mechanism of this effect are discussed based on experiments of MgB2 synthesis under 2 GPa pressure at 800 and 1,050 °C.