2013 Volume 54 Issue 12 Pages 2258-2264
MgB2 grains were coated with metal nanoparticles (Ag, Zn and Sn) using the barrel sputtering technique, and transport and superconducting properties were evaluated. Almost all MgB2 grains were uniformly coated with metal nanoparticles with average diameters of less than 20 nm. The electrical resistivity of the coated MgB2 decreased as the amount of metal coating increased. The critical current densities of almost all coated MgB2 were enhanced compared to those of bare MgB2. These results explained the improvement of intergranular connectivity between MgB2 grains by the insertion of metal nanoparticle in grain boundaries. After annealing at 473 K, only MgB2 coated with Sn nanoparticles showed a decrease in electrical resistivity and the enhancement of the critical current density. These results can be understood by the effect of improvement of intergranular connectivity between MgB2 grains by annealing.