Doping effect of Ag nanoparticles on critical current of YBa2Cu3O7-δ bulk superconductor

The objective of this work is to investigate the effect of Ag nanoparticles on critical current of YBa2Cu3O7-delta (YBCO) superconductor. Ag nanoparticles with different particle sizes from 30 to 1000 nm were prepared through the chemical reduction of AgNO3 in an alcohol solution. Then, samples of YBCO superconductors were doped by 1 and 2 wt.% of Ag nanoparticles with different sizes. Samples were characterized with XRD, SEM and EDX measurements. Critical current measurements were performed using a standard four-probe technique at liquid nitrogen temperature. The results showed by increasing of Ag nanoparticles up to 700 nm the J(c) increases, but decreases by further increase in Ag particles size. The critical current enhancement is attributed to the improved connectivity between the grain boundaries and better crystallization of the grains. (C) 2010 Elsevier B.V. All rights reserved.