Extended X-ray absorption fine structure study of Gd doped ZrO2 systems

ZrO2 samples with 7%, 9%, 11%, and 13% Gd doping have been prepared by co-precipitation route followed by high temperature sintering for potential application as high conductivity electrolytes in solid oxide fuel cells. The samples have been characterised by extended x-ray absorption fine structure (EXAFS) spectroscopy measurement around Gd L3 edge with Synchrotron radiation. The EXAFS spectra have been analysed to find out relevant local structure parameters of the Gd-O and Gd-Gd(Zr) shells, viz., bond distances, co-ordination numbers, and disorder parameters. The results were explained in the light of our earlier propositions from EXAFS measurements on the samples at Zr edge that Gd doping creates oxygen vacancies near the Zr sites and doping ∼9% is optimum for generation of oxygen vacancies in the ZrO2 matrix. The experimental results have also been corroborated by ab-initio first principle calculations of the energetics of the systems.