Direct interpretation of the X-ray and neutron three-dimensional difference pair distribution functions (3D-DPDFs) of yttria-stabilized zirconia

Three-dimensional difference pair distribution functions (3D-Delta PDFs) from X-ray and neutron diffraction experiments are reported for yttria-stabilized zirconia (Zr0.82Y0.18O1.91). A quantitative analysis of the signatures in the threedimensional difference pair distribution functions is used to establish that oxygen ions neighbouring a vacancy shift by 0.525 (5) angstrom along h1, 0, 0i towards the vacancy while metal ions neighbouring a vacancy shift by 0.465 (2) angstrom along h1, 1, 1i away from the vacancy. The neutron 3D-Delta PDF shows a tendency for vacancies to cluster along < 1/ 2, 1 /2, 1/ 2 >, which results in sixfold coordinated metal ions.