Study of Structural Modification in YBa2Cu3O7-y + x Sb2O3 Superconductor Composite
Keywords:HTSC, RAMAN, Electrical conductivity, Grain boundary, Microstructure.
A series of YBa2Cu3O7-y + x Sb2O3 (x = 0.0, 0.01, 0.03, 0.05, 0.08, 0.2 wt. %) samples were prepared using the solid state reaction method. The structural disorder has been studied using XRD and Raman techniques. XRD graphs show the unchanged orthorhombic structure. The increase in peak width of the XRD pattern in
the composites signifies the decrease in crystallite size with Sb2O3 addition. Raman analysis confirms all the
vibration modes in pure YBCO along with some peaks of antimony. The structural changes are marked by peak sifting in the XRD pattern and the softening in the Raman modes. Linear relation is portrayed between oxygen content and the c axis lattice parameter. The c axis tends to increase with the decrease in oxygen content
as calculated from XRD and Raman data. EDX analysis shows the incorporation of Sb2O3 to grain boundary region along with the presence of all the compositional elements. Microstructure analysis has been studied through SEM. SEM graphs shows that pristine YBCO exhibits large and elongated grains randomly oriented
in all directions. The grain size decrease in low wt. % addition of Sb2O3 and increase in higher wt. % addition.