Magnetic Field Dependence of Critical Current Density in Silver-Doped Y-Ba-Cu-O Superconductors
Effects of silver doping on critical current density in the bulk superconductor Y-Ba-Cu-O system are investigated by measuring the variation of critical current density in low magnetic fields. Below a newly defined characteristic field value Hc’, the critical current is mainly controlled by intergranular effects due to Josephson weak-link coupling. This field Hc’, which signifies a crossover between regions dominated by inter- and intra-granular effects, is found to vary with the silver content. An optimum enhancement of both the critical current density and Hc’ is obtained with silver doping around 5 – 10%. These results lend direct support to the interpretation that the Josephson coupling is enhanced due to the presence of silver atoms along the grain boundaries in the material.
KeywordsCritical Current Density Magnetic Field Dependence Silver Cluster Superconducting Order Parameter Semilog Plot
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