Coherence Length and Transport Critical Current Density in Y3Ba5Cu8O18-δ/Co Composite Superconductor

Abstract

We have investigated how the low concentrations of ferromagnetic Co-nanoparticles in intergranular networks of multi-layered Y₃Ba₅Cu₈O_18-δ (Y358) superconductor affect the coherence length (ξ_c) at absolute zero temperature and critical current density, J_c, near the superconducting phase transition region. Fluctuation-induced conductivity (FIC) is used to extract ξ_c (0). An increasing trend of ξ_c (0) with increasing concentration of Co is observed, attributed to the deterioration of the superconducting properties. We have extracted J_c from current–voltage (IV) characteristics in the phase transition region. Reduction in J_c has also been observed with increasing the concentration of Co-nanoparticles.