Films of PMMA and PMMA doped with NiCl 2 with different contents were prepared using the casting technique. The optical properties of all films were investigated using spectrophotometric measurements of absorbance and transmittance in the wavelength range 200-800 nm. The change of the calculated values of the optical energy gaps with increasing NiCl 2 content has been interpreted in terms of the structural modifications of the PMMA matrix. The optical energy gap decreased from 3.6 to 3.05 eV with increasing the NiCl 2 concentration to 0.4%. The effect of doping on the optical constants of films such as refractive index, extinction coefficient, real and imaginary parts of dielectric constant, optical conductivity, and skin depth has been reported. All these constants were increased with increasing NiCl 2 concentration with the exception of skin depth which is different result.
Investigating the Preparation Conditions on Superconducting Properties of Bi 2−x Li x Pb 0.3 Sr 2 Ca 2 Cu 3 O 10+δ. Materials Sciences and Applications, 6, 310-321.
Bi 17 Pb 0.3 Sr 2 Ca 2 Cu 3 O 10+δ superconductor samples were synthesized by the conventional solid-state reaction method. To study the effects of the addition of yttrium nanoparticles to the superconducting system, nano Y 2 O 3 was introduced by small weight percentages (0.2, 0.4, 0.6, 0.8, and 1.0 wt%) in the first step of the synthesis process. Phase identification and microstructural characterization of the samples were investigated using X-ray diffraction and scanning electronic microscopy (SEM). Energydispersive X-ray spectroscopy (EDX) analysis was utilized to confirm the presence of the desired elements in the chemical composition of the samples. Moreover, DC electrical resistivity as a function of the temperature, critical current density (J c ), AC magnetic susceptibility, and DC magnetization measurements were carried to evaluate the relative performance of samples. XRD analysis showed that both (Bi,Pb)-2223 and Bi-2212 phases coexist in the samples having an orthorhombic crystal structure. Both the onset critical temperatures (T c ) (onset) and zero electrical resistivity critical temperatures (T c ) (R = 0) of the samples were determined from the DC electrical resistivity measurements. An improvement of the superconducting transition temperature of 3.0 % was obtained with increasing Y 2 O 3 nanoparticles to x = 1.0 wt%, while the critical current density is improved by 200 %. AC magnetic susceptibility measurement showed that the diamagnetic fraction and intergranular coupling of the x = 1.0 wt% sample are greater than those of the others. The variation of magnetization with temperature (M-T curve) of the samples was measured by cooling the sample in zero fields (ZFC) and an applied field of 10 Oe (FC). The results of AC magnetic susceptibility and DC magnetization measurements were in good agreement with DC electrical resistivity measurement.
Effect of adding silver nanoparticles on Bi1.7Pb0.3Sr2Ca2Cu3O10+δ superconductor phase by solid state reaction technique. It was studied the significant variations in the superconducting, magnetic and structural properties of Bi-2223 phase. Ag NPs concentration of tiny particles varied, (0 - 1,25) % from the total weight mass of the BPSCCO compound were characterized by X-ray diffraction (XRD) and EDX spectrum measurements. It was found that adding Ag nanoparticles to BSCCO was enhanced the (Bi, Pb)-2223 phase formation up to x=1.25 wt%. On the other hand, the low concentrations of Ag nanoparticles of 0.25 wt% retarded the high-Tc phase formation and (Tc) measured that had the maximum improvement in Tc for most samples. The surface morphology investigated were examined by SEM, which the grain size increased with an increase Ag NPs, while the grain size examination showed that both the size and number of voids were reduced. Magnetization variance was measured of the samples by M - T curve, where the highest value for x = 1.25 wt%, and it become clear when the magnetic and resistance transition points are close to each other. Moreover, Critical current density (Jc
) characteristic curves were measured at temperature range (2-150) K.
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