The BiI.7Sbo.JSr..,.,cal.OlCuJ.IOy superconductors are prepared by
sol·gel method and the effect ofW~ and MnOz additives on their properties
are studied. Structural studies show that the find samples are homogeneous
and are mainly composed of 2223 and lower percents of 2212 phases.
Analysis ofthe X-ray diffraction patterns indicate that the penetration of~
ions into superconducting phase considerably increases for more than 2 wt%
additives. Also. the penetrating ~ ions preferentially occupy 4e and 2a
crystallographic sites of eu atoms. The electrical measurements show that
the best superconducting properties obtain for the sample with I wt% of
WOJ additive, while superconductivity is weakened for higher amounts of
WO,. For the sample with O.S wt% of MnOz additive, the best
superconducting properties are obtained after sintering at 830 OC.

In this article, we have employed GSAS software to do Reitveld profile refinement on XRD patterns from H-T_c superconductor powder YBa2_-xK_xCu₃O_7-y (02. On the other hand, substituting of K instead of Ba led to oxygen depletion and also lowering the Ba (K) plane position along the Z direction (||c). The structural phase ratio of tetragonal to orthorhombic increased and it means that the superconductivity exist even in samples with dominant tetragonal phase.

In this paper Sb₂O₃ nanoparticles are synthesized by solution method. The effect of these nanoparticles on the Bi-2223 superconductor properties has been investigated. The critical temperature, critical current density and activation energy were measured by the standard four-probe method. Magnetic properties of the samples were measured by using the AC magnetic susceptibility. The microstructure and morphology of samples have been studied by X-ray diffraction, scanning electron microscope and energy dispersive X-ray. The results of X-ray diffraction patterns show that the low amount of Sb₂O₃ and long annealing time enhance the fraction of Bi -2223 phase. Also the results show that the Sb₂O₃ nanoparticles do not change the phases and critical temperature of Bi-2223 superconductor, but by increasing the amount of Sb₂O₃ nanoparticles, the critical current density and the activation energy of the samples increase.

In this research, YBa₂Cu₃O_7-d (0 < d < 1) nanocrystalite superconductor was prepared by mechanochemical alloying method. We synthesized YBa₂Cu₃O_7-d via mixing the BaCO₃, Y₂O₃, CuO powders and milling in SPEX 8000 for 5h with weight ratio of ball to powder 10:1 and steel balls of 11mm diameter, followed by heating for 4h at 850 ˚C. The superconductor phase formation process was completed with sintering treatment under oxygen partial pressures.The superconducting transition temperature of the samples was investigated using the four-probe method. Then transition temperature of xMnO₂ + (1-x) YBa₂Cu₃O_7-d compounds was studied. The superconducting transition temperature of the final samples with x = 0, 0.005, 0.01 is found to be 83 K, and for the samples with x > 0.015, the superconductivity was vanished.ر

Gd₂O₃ nanoparticles were synthesized for the first time by sol-gel combustion method and YBCO high temperature superconductor by sol-gel method. X-ray powder diffraction pattern of the nanoparticles and prepared superconductor showed single phase by both methods. The average size of Gd₂O₃ nanoparticles, according to the Scherrer formula, computed 29 nm, which is consistent with the results obtained from the TEM images. The nanoparticles with two weight perecent of 0.05 and 0.1 were added to YBCO superconductor. The morphology, structure and superconducting properties investigated by scanning electron microscopy, X-ray diffraction and AC susceptibility in product powders respectively. Rietveld refinements from X-ray diffraction data and results of characteristic showed that both Gd₂O₃ and YBCO phases coexisted in the products and critical temperature of superconductor decreased with increasing additive content.

In this paper, the CdO nanoparticles were prepared by chemical reduction method. Then, the CdO nanoparticles were doped in the Bi_1.64Pb_0.36Sr₂Ca_2-xCd_xCu₃Oy with
 x = 0.0, 0.01, 0.02, 0.03, 0.04, 0.1 superconductor.  The samples were synthesized by the standard solid-state reaction technique. The structural properties, microstructure and morphology of the samples have been studied by XRD, SEM and TGA-DTA. After synthesizing the samples and observing the Meissner effect, the study of the crystallography, critical current density (Jc), critical temperature (Tc), SEM, and Thermogravimetry-Differential thermal analysis shows of samples have been down. The results of the critical current density measurements show that the sample with x = 0.01, with annealing time 270h and the size of 16nm, has the maximum JC. Although the critical tempeprature increases with subittiution of Cd for Ca but the results of the critical temperature measurements of the samples with the CdO nanoparticles reveal that no remarkable increasing in the critical temperature was observed. With increasing annealing time, critical temperature and critical current density of all samples increases too.  

In this paper, β-PbO nanoparticles were prepared by microwave irradiation. Then, the PbO nanoparticles with size of 32 nm were doped in the Bi_2-xPb_xSr₂Ca₂Cu₄O_y superconductor with x = 0.0, 0.2, 0.4 and 0.6. The samples were synthesized by the standard solid state reaction method. The structural properties, microstructure and morphology of the samples have been studied by XRD and SEM. After synthesizing the samples and observing the Meissner effect, the study of the critical current density (J_c), critical temperature (T_c) and thermogravimetry-differential thermal analysis shows that samples have been down. The results of the critical current density measurements show that the sample with x = 0.4 and an annealing time 60 h has the maximum J_c. Substitution of PbO nanoparticles for Bi reveal that remarkable increases in the critical temperature. The volume of the unit cell of doped samples were increased with respect to that of the undoped samples, which is shown Bi⁺³ substituted by Pb⁺².