High-pressure XAFS study of pure ZrO₂ and stabilized cubic ZrO₂

X-ray absorption fine structure (XAFS) measurements near the Zr K-edge for pure ZrO₂ and stabilized cubic ZrO₂ (+8% Y ₂O₃) were performed under pressure up to 7.8 GPa using a multi-anvil high-pressure device and synchrotron radiation at BL14B1, SPring-8, Hyogo. The edge feature of XANES spectra for stabilized ZrO₂ with defect-fluorite type structure looks like an addition of both shapes for the P2₁/c and Pbca phases in pure ZrO₂. The pressure dependence of Zr-O distances is almost similar in the pure and stabilized ZrO₂. The contribution of the thermal vibration can be extracted from σ2 by temperature-dependent EXAFS experiments. The contribution of static disorder is extremely large compared with other super ionic conductors. The potential coefficient a for an effective pair potential, V(u) = au ²/2, has been evaluated from the experimental σ2 and is 8.44(6) eV Å^-2. Local structure and compression effect for stabilized cubic ZrO₂ especially looks like those in the Pbca phase of pure ZrO₂.