Investigation of some physical properties of silver diffusion-doped YBa2Cu3O7-x superconductors

Silver diffusion in superconducting YBa2Cu3O7-x (YBCO) has been studied over the temperature range 500-800 0C by x-ray diffraction measurements. The diffusion coefficient of Ag in YBCO was determined from the observed increase (0.12%) in the lattice parameter c as compared with the undoped sample. It was shown that the diffusion coefficient of Ag in the temperature range 500-800 0C changed from 1 x 10-10 to 5 x 10-9 cm2 s-1 with an activation energy of about 1.06 eV. For the Ag-doped sample, the critical transition temperature and the critical current density were increased from 90 to 92.5 K and from 60 to 98 A cm-2 respectively in comparison with those of undoped YBCO. The possible reasons for the observed increases in Tc and Jc due to Ag diffusion were discussed