Electrical properties and fluctuation induced conductivity studies of Bi-based superconductors added by CuS nanoparticles synthesized through the aqueous route

Abstract

The effect of copper sulfide (CuS) nanoparticles synthesized by aqueous route on the electrical transport and on the fluctuation induced conductivity of polycrystalline (Bi,Pb)2Sr2Ca2Cu3Oy (denoted Bi-2223) was reported. The global critical current densities versus temperature, Jct(T), at self and applied magnetic field was analyzed within the collective pinning model. The electrical resistivity versus temperature, ρ(T), above the mean-field temperature Tc was analyzed using Aslamazov-Larkin (AL) and Lawrence-Doniach (LD) models. Different fluctuation regimes indicated by short-wave region (SWR), three-dimensional (3D), two-dimensional (2D), one-dimensional (1D), and critical region (CR) fluctuations were identified. The zero-temperature coherence length, the effective layer thickness, the critical magnetic fields, and the critical current densities are determined. It was found that samples sintered with an additional amount of CuS nanoparticles (< 0.4 wt%) exhibit higher upper critical magnetic fields and critical current densities compared to the pure one and the highest values of these parameters are obtained in the 0.2 wt% CuS added sample. Consequently, the addition of CuS nanoparticles could introduce strong pinning centers that contribute to the decrease of magnetic vortex motion which enhances the flux pinning capacities and the transport abilities inside the Bi-2223 system.