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Open Access Research Article Issue
Magnetoresistivity studies for BiPb-2223 phase added by BaSnO3 nanoparticles
Journal of Advanced Ceramics 2017, 6 (2): 100-109
Published: 03 June 2017
Downloads:18

Co-precipitation method and conventional solid-state reaction technique were used to synthesize BaSnO3 nanoparticles and (BaSnO3)x/Bi1.6Pb0.4Sr2Ca2Cu3O10+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 Tc 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 Jc (0) estimated from AH parameter C(B), and upper critical magnetic field Bc2(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 κe above the superconducting transition temperature and suppressed it below Tc .

Open Access Research Article Issue
Superconducting parameter determination for (Co0.5Zn0.5Fe2O4)x/Cu0.5Tl0.5-1223 composite
Journal of Advanced Ceramics 2016, 5 (3): 210-218
Published: 21 August 2016
Downloads:9

The addition of magnetic Co0.5Zn0.5Fe2O4 nanoparticles to the superconducting Cu0.5Tl0.5-1223 phase has been used to investigate the electrical resistivity behavior of the composite above the superconducting transition temperature Tc. 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 (Tscf) change by increasing the addition of Co0.5Zn0.5Fe2O4 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 Tc, 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 (T3D–2D) in the mean field region was decreased by increasing the addition of Co0.5Zn0.5Fe2O4 nanoparticles, in accordance with the decrease in Tscf with x. The coherence length at 0 K along c-axis ξc(0), effective layer thickness of the 2D system d, and inter-layer coupling strength J were estimated as a function of Co0.5Zn0.5Fe2O4 nanoparticle addition. Moreover, the thermodynamics, lower and upper critical magnetic fields, as well as critical current density have been calculated from the Ginzburg number NG. It was found that the low concentration of Co0.5Zn0.5Fe2O4 nanoparticles up to x = 0.08 wt% improves the superconducting parameters of Cu0.5Tl0.5-1223 phase. On the contrary, these parameters were deteriorated for (Co0.5Zn0.5Fe2O4)x/Cu0.5Tl0.5-1223 composite with x > 0.08 wt%.

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