Structural investigation of Y3Ba5Cu8O18+ and Y3Ba5Ca2Cu8O18+ superconductor samples

In this study, Y3Ba5Cu8O18 and Ca doped Y3Ba5Ca2Cu8O18 superconductor compounds were prepared by using the sol-gel method. Before the compounds were prepared, their structural properties were investigated in detail from the literature. For this reason, in the first part of this work; the microstructural and physical properties of superconductivity and superconducting families, including LBCO, BSSCO, HBCCO and YBCO have been summarized. Micro structural and physical properties of both undoped and Ca doped samples were investigated by using Differantial Thermal Analysis (DTA), Thermo Gravimetric Analysis (TGA), Electrical Resistivity Measurements (R-T), Activation Energy Measurement, Scanned Electron Microscope (SEM), Energy Dispersion Spectrum (EDX), X-Ray Difraction Pattern (XRD) and Atomic Force Microscope (AFM). Structural analyses show that Y3Ba5Cu8O18 and Y3Ba5Ca2Cu8O18 superconductors are formed perfectly and exhibit characteristic features of YBCO family, however, it has been observed that the Ca doping effects the superconductivity in negative direction. I.e., Tc shifts to lower temperatures and the transition is not so sharp.