Investigation of structural, electrical and mechanical properties of Co doped YBCO-358 polycrystalline superconductors produced by solid state reaction method

In this study, we aimed to analyze effect of Co nanopowder partial substitution with Cu in the Y 3 Ba 5 Cu 8-x Co x O 18-δ system with x=0, 0.05, 0.1, 0.15, 0.2 by performing X- ray Diffractometer (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Vicker's Microhardness Tester and Electrical Resistivity Measurement System (R-T). The conventional solid state reaction method chosen to fabricate the system. In the fabrication process we applied 930oC for 24 hours after 3 times calcination at 850oC 24h. From the XRD and resistance versus temperature measurements, it was found that the crystal structure of the obtained samples except Y358-50 did not deviate from the orthorhombic structure by doping, while the zero resistivity of the produced samples decreased with increasing Co nanoparticle concentration in the system. As a result of increasing of doping amount in the system, the microhardness values of the produced bulk samples changed. All samples showed reverse indentation size effect behavior (RISE).