The structure analyse with doping atoms on bizmuth based ceramic superconducters

In this thesis, effect of Sb doping on the critical temperature, sperconductivity and structural properties of Bi1,75Pb0,25Sr2Ca2Cu3-xSbxOy ceramic superconducters were investigated. Partial molar replacement of Bi by Sb was investigated in x=0,00-0,20 substitutional range. Samples, which were prepared by conventional solid state reaction method; sintered at 850 0C after applying pelletization pressure at 450-500 mPa range. Critical temperatures of samples and magnetization-temperature dependence were determined by VSM system applying 55 Oe magnetic field. XRD measurements were done by powder x-ray diffraction method. Superconductor phases and crystal lattice paremeter were determined. Data on the microstructure of samples were obtained from scanning electron microscope (SEM) photographs. The weight ratios of elements in different regions of sampleswere investigated by EDAX analysis. Data on the granular structure of samples were obtained from scanning electron microscope (SEM) photographs with x2000, x3500, x8000, x10000, x15000 magnifications. The density values for all samples were determined by using Arshimed methods. Comparison the results obtained from magnetizaion- temperatre, XRD measurements, SEM microphotographs and calculated unit cell paremeters indicate that the strucural and superconducting properties are better for sample C (x=0,10). Superconductivity phases were disappeared and structure was disordered by increasing doping ratios.