Relationship between MgO particles addition and critical current density in Bi-2212 thick film grown on oxidized Ni substrate

Abstract

In order to substitute cheaper metal for Ag, superconducting Bi-2212 thick films were prepared on an oxidized Ni substrate. As one of the approaches enhancing the critical current characteristic in Bi-2212 thick films, several percent of fine MgO particles were doped during the specimen fabrications. The detailed investigations on MgO particles doped in Bi-2212 and their effect on the critical current density ( J c) were carried out. The results of EPMA analysis show that MgO particles disperse uniformly in Bi-2212. Apparent enhancements in J c were obtained in specimens with several volume percent of MgO doped, which is fairly similar to the results from the superconducting Bi-2212 bulk materials in our previous study. Since no apparent differences in physical and chemical properties could be recognized between the specimens with and without MgO particles doped, the enhancement of J c implies that the MgO particles act as effective flux pinning centers.