We synthesized the YBa m Cu 1+m O y superconductors; m = 2, 3, 4, 5 that were Y123 ( YBa 2 Cu 3 O 7-x), Y134 ( YBa 3 Cu 4 O 9-x), Y145 ( YBa 4 Cu 5 O 11-x), Y156 ( YBa 5 Cu 6 O 13-x), by solid state reaction with the Y 2 O 3, BaCO 3 and CuO as the beginning materials. The calcination temperature was 950°C and varied the sintering temperature to be 950°C and 980°C. The resistivity measurement by four-point-probe technique showed that the Tconset of Y123, Y134, Y145, Y156 were at 97, 93, 91, 85 K, respectively. The XRD and Rietveld full-profile analysis method were used and found that the crystal structure was in the orthorhombic with Pmmm space group with the ratio c/a were 3.0, 4.0, 5.0 and 6.0 for Y123, Y134, Y145 and Y156, respectively. The oxygen content was characterized by Iodometric titration. The ( Cu 3+/ Cu 2+ and Oxygen content) were (0.28, 6.83), (0.19, 8.81), (0.13, 10.79), (0.16, 12.92) of Y123, Y134, Y145, Y156, respectively. We also found that the increasing of sintering temperature has reduced the oxygen content and the critical temperature of all samples.

In this research, we synthesized and characterized the physical properties of YBa2Cu3Ox (Y123) and YBa4Cu5Ox (Y145) superconductors by solid state reaction and melt process. The raw materials Y2O3, BaCO3 and CuO were mixed, ground and react in the air atmosphere at 950 °C, at 980 °C for solid state reaction and melt process, respectively. The samples obtained were characterized by the resistivity measurement, SEM, EDX, XRD and DTA. It was found that the critical temperature onset of Y145 is 94 K and 96 K for solid state reaction and melt process, respectively. The samples were inhomogeneous with no impurity. The crystal structures was orthorhombic which a = 3.80446 Å, b = 3.86474 Å and c = 19.37104 Å for Y145 solid state reaction and a = 3.80180 Å, b = 3.86483 Å and c = 19.38194 Å for melt process. The peritectic temperature of Y145 is 1018 °C.

In this research, we synthesized Y123 superconductor and Y235 superconductor doped with fluorine by solid sate reaction with Y2O3, BaCO3, CuO and CuF2 as precursor. The physical properties of Y235+Fx (Y2Ba3Cu5Oy-xFx) and Y123+Fx (YBa2Cu3Oy-xFx) superconductors were studied at x = 0,0.1, 0.2. The calcinations process was done twice in air at 810 °C for 24 hr and was increased to 925 °C for one hour. The sintering process was done at 925 °C for 24 hr and reduced to 500 °C for 24 hr. Our samples obtained were characterization by the four point probe technique, SEM and EDX, respectively. The surface of all samples were inhomogeneous and no impurity. The critical temperature onset of Y123+Fx and Y235+Fx were equal to 92 K, 95 K, 93 K and 92 K, 93 K, 92 K with x= 0, 0.1, 0.2, respectively.

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.