AC Magnetic Susceptibility Measurement of High Temperature YBCO Superconductor Doped by Silver Nanoparticles

In this study, the effect of of silver nanoparticles (Ag-NPs) inclusion on the AC magnetic susceptibility of high temperature YBa2Cu3O7-δ  (Y123) + x wt% Ag (x=0.00, 0.06, 0.10 and 0.30)  polycrystalline superconductors was investigated. The high temperature superconductors (Y123 + x wt% Ag) were fabricated by  the solid state reaction method. XRD analysis of the samples showed superconducting orthorhombic phase with symmetry of Pmmm space group. Analysis of scanning electron microscopy (SEM) images related to the surface morphology of the samples showed that increasing silver nanoparticles dopant causes a decrease in granule size of the compounds. Real magnetic susceptibility exhibited intrinsic diamagnetic behavior and grain boundary connections and imaginary components of magnetic susceptibility showed energy loss due to flux penetration and vortex movement at the grain boundary. The critical temperature of 92 K was obtained for pure Y123 by real component of magnetic susceptibility and complete diamagnetism was observed in all samples (x=0.00, 0.06, 0.10 and 0.30). Silver decreased the critical temperature and increased the critical current density. Based on the obtained values of maximum Josephson current and Josephson intergranular energy coupling, it can be concluded that x=0.10 is the best weight percentage for Ag among the Y123 doped samples. Indeed, the greater inter-granular Josephson coupling energy causes, the superior of the trapping force and consequently produces the better critical current density.