EFFECT OF WO3 DOPING ON THE PROPERTIES OF YBA2CU3O7-X SUPERCONDUCTOR

Tungsten-doped YBa2Cu3O7-x superconducting samples are characterized with the help of resistivity, crystal structural, microstructural, density d, and critical current density Jc studies for doping concentrations varying from 0.00 to 0.14 mol % of WO3. It has been found that doping of WO3 has hardly any influence of T c, whereas it seems that d and Jc are affected. d and Jc of the samples increase in the range 0<WO3≤0.04, but above this range, both start decreasing. The maximum Jc obtained at 77 K and zero magnetic field in YBa2Cu3O7-x doped with 0.04 mol % of WO3 is 450 A/cm2. The lower concentrations (<0.04 mol %) seem to improve the density, whereas higher concentrations lead to porous structure and also induce the formation of BaCuO2 and Y2Ba1Cu1O5 nonsuperconducting phase as revealed by scanning electron microscopy, energy dispersive spectral, and x-ray diffraction analyses. The x-ray diffraction analysis also showed no appreciable change in the lattice parameters with WO3 doping. It appears that the WO3 doping changes the microstructure of YBa2Cu3O7-x to influence its Jc.