Enhanced flux pinning and critical current density in YBa2Cu3O7-d through dual nanoparticle doping: A comparative investigation of PbO/semiconductor oxide and Ag/semiconductor oxide

The distinctive feature of this work lies in the role of co-adding different types of nanoparticles ($\text{NPs}$) systems to enhance magnetic flux pinning ($\text{MFP}$) and critical physical parameters ($\text{CPP}$). Two different types of $\text{NPs}$ inclusion in YBa₂Cu₃O_7-d ($Y123$) material are considered, namely metal-semiconductor ($M-\text{SC}$) or semiconductor-semiconductor ($\text{SC-SC}$). The primary metal and semiconductor additives selected are $Ag$ and $PbO$, while $Ti{O}_2$ and $W{O}_3$ serve as secondary $SC$ additives. Phase purity was confirmed through powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM) analysis. Electrical conductivity analysis near the beginning of the superconducting transition ($\text{ST}$) was used to calculate key $\text{CPP}$ at temperature 0K, such as the critical current density $J_{co}$, the lower and the upper critical magnetic fields, $B_{co1}$ and $B_{co2}$, respectively, and the flux creep activation energy ($U_a$) was extracted from electrical resistivity close to the end of ST. Despite the presence of Ag along with $\text{SC}$ that advances the transition to the superconducting state, mixing $\text{PbO}$ and $W{O}_3$ in the $Y123$ proved to work better for vortex pinning traits, and strengthening the $\text{CPP}$ and characteristics of the grain coupling barriers.