Co-precipitation method and conventional solid-state reaction technique were used to synthesize BaSnO₃ nanoparticles and (BaSnO₃)_x/Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O_10+δ (0 ≤ x ≤ 1.50 wt%) samples, respectively. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and electrical resistivity data were used to characterize BiPb-2223 phase added by BaSnO₃ nanoparticles. The relative volume fraction and superconducting transition temperature T_c of BiPb-2223 phase were enhanced by increasing BaSnO₃ addition up to 0.50 wt%. These parameters were decreased with further increase of x. The resistive transition broadening under different applied DC magnetic fields (0.29-4.40 kG) was analyzed through thermally activated flux creep (TAFC) model and Ambegaokar-Halperin (AH) theory. Improvements of the derived flux pinning energy U, critical current density J_c (0) estimated from AH parameter C(B), and upper critical magnetic field $B_{\text{c2}}\text{(0)}$, were recorded by adding BaSnO₃ nanoparticles up to 0.50 wt%, beyond which these parameters were suppressed. The magnetic field dependence of the flux pinning energy and critical current density decreased as a power-law relation, which indicated the single junction sensitivity between the superconducting grains to the applied magnetic field. Furthermore, the increase in the applied magnetic field did not affect the electronic thermal conductivity ${\kappa }_{\text{e}}$ above the superconducting transition temperature and suppressed it below T_c .

The addition of magnetic Co_0.5Zn_0.5Fe₂O₄ nanoparticles to the superconducting Cu_0.5Tl_0.5-1223 phase has been used to investigate the electrical resistivity behavior of the composite above the superconducting transition temperature T_c. This was studied according to the opening of spin gap and fluctuation conductivity. The results indicated that the pseudogap temperature (T^*) and superconducting fluctuation temperature (T_scf) change by increasing the addition of Co_0.5Zn_0.5Fe₂O₄ nanoparticles. It was found that T^* is related to hole carrier concentration P and it also depends on the antiferromagnetic fluctuation affected by magnetic nanoparticles. The excess-conductivity analysis showed four different fluctuation regions started from high temperature up to T_c, and they were denoted by short wave (sw), two-dimensional (2D), three-dimensional (3D), and critical (cr) fluctuations. The crossover temperature between 3D and 2D (T_3D–2D) in the mean field region was decreased by increasing the addition of Co_0.5Zn_0.5Fe₂O₄ nanoparticles, in accordance with the decrease in T_scf with x. The coherence length at 0 K along c-axis ξ_c(0), effective layer thickness of the 2D system d, and inter-layer coupling strength J were estimated as a function of Co_0.5Zn_0.5Fe₂O₄ nanoparticle addition. Moreover, the thermodynamics, lower and upper critical magnetic fields, as well as critical current density have been calculated from the Ginzburg number N_G. It was found that the low concentration of Co_0.5Zn_0.5Fe₂O₄ nanoparticles up to x = 0.08 wt% improves the superconducting parameters of Cu_0.5Tl_0.5-1223 phase. On the contrary, these parameters were deteriorated for (Co_0.5Zn_0.5Fe₂O₄)_x/Cu_0.5Tl_0.5-1223 composite with x > 0.08 wt%.