Preparation and Characterization of the Sn x Ba 4 Ca 2 Cu x+4 O y and Y n Ba 5 Cu Compounds

The present study includes the preparation of Sn xBa4Ca andYnBa5Cun+5O compounds with (x = 3, 4, 5, 6, 7) and (n=3, 5, 7) by solid state reaction (SSR) method. The study was to conclude the erconductor behavior of both compounds. The prepared samples were analyzed by Meissner effect primary, and the excess oxygen content was measured by using Iodomertric titration method. The samples characterized by XRD patterns with computer program that was used to determine the value of lattice constant, Scanning Electron Microscope (SEM), Energy dispersive Xray spectroscopy (EDS) to study the grain morphology and also resistivity measurement was performed by Van der Pauw method to conclude the nature of behavior. yThe resistivity measurement results of Sn-Ba-Ca-Cu-O system showed that the semiconducting behavior, increases with decreasing the temperature toward low temperature, the lowest and the highest normal resistivity were found at x=6 and at x=4, respectively. The system Y-Ba-Cu-O showed a2Cux+4Oy superconductor behavior with high transition temperature, the T at n=3 of about (113.6 K), the sample prepared with n=5 has Tc=113 K, meanwhile the sample prepared with n=7 has Tc=105 K. The x-ray analyses for SnxBa4Ca2Cux+4O samples showed that the tetragonal structure, and the c-parameter increased by increasing the value of (x) until reach to maximum value at x=5 then return back decreasing at x=6 and 7. The x-ray diffraction analysis of the compound YynBa has orthorhombic phase and when Y-atom concentration and the number of CuO layer increased tend to increase b and c-axis. The Scanning Electron Microscopy (SEM) results showed that the appearance of nanostructure in Sn 6Ba4Ca2Cu10O22 and Snsamples in the range (100-300 nm), whereas the other samples of Sn-family 75BacCu4n+5Ca2OCuy11O224 was a microstructure. On the other hand, the Y-358 had large grains randomly comparable with Y-5 5 10, Y-7 5 12 addition to absent the interfaces distances from Y-358. The results of EDS showed that the agreement of the peaks appeared with the theoretical values.