Distribution of MgO nanoparticles in Bi-2212/Ag tapes and their effect on the superconducting properties

Bi-2212/Ag tapes are fabricated by a combination of dip-coating and partial melt processing. We investigate the effect of addition of MgO particles obtained by Mg combustion. Two different methods of MgO particle embedment in the Bi-2212 matrix are applied. Microstructural studies of processed tapes show that the distribution of MgO particles in the Bi-2212 matrix depends on the methods of tape preparation. If particles were added to the slurry, MgO formed clusters, which depressed Bi-2212 grain alignment and led to degradation of the tape's transport properties. MgO particles, introduced in the Bi-2212 matrix by direct deposition during Mg combustion, significantly enhance the transport properties of the tapes. This improvement also depends on the magnitude of the magnetic field and operating temperatures. At 25 K, the Bi-2212 tape with the MgO added by direct deposition has 2.5 times higher J(c) value compared to the tapes without MgO doping.