Direct interpretation of the X-ray and neutron 3D-$Δ$PDFs of yittria stabilized zirconia
Three dimensional difference pair distribution functions from X-ray and neutron diffraction experiments are reported for yttria stabilized zirconia (Zr$_{0.82}$Y$_{0.18}$O$_{1.91}$). We use a quantitative analysis of the signatures in the 3D-$Δ$PDFs to establish that oxygen ions neighbouring a vacancy shift by 0.515(5)~Å along $\langle 1,0,0 \rangle$ towards the vacancy while metal ions neighbouring a vacancy shift by 0.269(2)~Å along $\langle 1,1,1 \rangle$ away from the vacancy. The neutron 3D-$Δ$PDF shows a tendency for vacancies to cluster along $\langle \frac{1}{2},\frac{1}{2},\frac{1}{2}\rangle$, which results in 6-fold coordinated metal ions.
cond-mat.mtrl-sci↗