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The bulk samples of milled and unmilled synthesized by conventional solid-state reaction. The powder X-ray diffraction and Rietveld refinement software program characterized crystal structure. The elementary mapping technique was used EDXS. For the onset critical temperature (Tconset) and offset critical temperature (Tcoffset) the four-probes measurement method was utilized. The superconducting compound and non-superconducting compound were incorporated in the samples. The Y123 was highest superconducting compound and lowest the non-superconducting compound. The clattice parameter of milled samples was longer than unmilled samples. The anisotropy parameter of the milled samples had a lower value than the unmilled samples. The mapping technique showed that the without any impurity and composite of Y, Ba, Cu, and O. The critical temperature of milled, Y358, and Y7-11-18 were higher than unmilled. Conversely, the critical temperatures of milled and unmilled Y123 were closed to Y358 and Y7-11-18.

In this paper, the Y145 superconductor doped Ag2O were synthesized by solid state reaction. The calcinations and sintering temperature were at 920 °C and annealing temperature was at 550 °C. The highest critical temperature was in Y145+0.1Ag sample with Tc onset at 96 K and the lowest was found in pure Y145 at 95 K. We found that the surface of Y145 superconductor was improved by Ag adding on the porous structure.

In this paper . W e synthesized Y134 superconductor doped Ag2O by solid state reaction and investigated the effect of Ag2O addition on the critical temperature of Y134 superconductor and SEM micrographs shown Y134 doped Ag2O has rather smooth and small pores feature . The maximum critical temperature found at an optimal doping ,0.1 Ag, with Tc onset =97 K.

The YBa5Cu6Ox (Y156) superconductors were synthesized by melt process method with sintering at 980 °C. The samples were characterized by the SEM, EDX, XRD and resistance measurement. The critical temperature onset () and the critical temperature offset () were found at 90 K and 80 K respectively. The crystal structures was orthorhombic performed by Rietveld full-profile analysis method with lattice parameter a = 3.80078 Å, b = 3.89068 Å and c = 22.94436 Å. The c/a ratio was 6.04 and the anisotropy was 2.33. The lower c/a ratio and higher anisotropic were found as increasing the sintering temperature with little change in a and b-axis value. We found that as increasing of sintering temperature, the critical temperature was decreased but the anisotropy was increased.

In this research, the Y123 (YBa2Cu3Ox) and Y134 (YBa3Cu4Ox) superconductors were synthesized by solid state reaction and melt process, respectively. The crystal structure of all the samples were then determined using the Rietveld full-profile analysis method to indicate orthorhombic structure. The resistivity measurements showing Tc onset of Y123 lower than Y134 for solid state reaction but higher than Y134 melt process. However, the critical temperature off-set of Y134 has lower than of Y123. The SEM and EDX show that all samples were inhomogeneous. The SEM micrograph for solid state reaction Y123 has many pores between the grain and the grain size clearly demonstrated and bigger than Y134. It was seen that these pores are party eliminated in melt process samples. FTIR spectra detected the trace of carbonate residue in all samples.

The new superconductors of Y-based compound, Y7Ba11Cu18Oy(Y7-11-18), has been discovered by solid state reaction with the different ratios of raw materials. All obtained samples were analyzed and characterized by XRD and the FULLPROF program. The lattice parameters of Y7-11-18 were a=3.8268 Å, b=3.8810 Å and c= 69.8794 Å. The Y7-11-18 showed the sharp transition curve of resistivity (ρ) at the critical temperature (Tc) =94 K. The doping of Y2BaCuO5 (Y211) showed that the higher Y211, the lower Tc and c lattice parameter. The SEM and EDX micrographs showed the grain size about 1-5 μm and without impurities. The DTA analysis resulted the decreasing of peritectic temperature from 962.74 oC by the higher Y211 contents.