Atomistic configurations of yttria-stabilized zirconia between 3 and 10 mol % ${\mathrm{Y}}_2{\mathrm{O}}_3$ were relaxed using the pseudopotential technique. The results showed a phase transition to the cubic (c) $\left({\mathrm{ZrO}}_2{)}_{100-x}\right({\mathrm{Y}}_2{\mathrm{O}}_3{)}_x$ at $x\sim 10\mathrm{mol}\%.\mathrm{}$ The electron-energy-loss near-edge spectra, calculated using the linear muffin-tin orbital method and relaxed defect geometry, agree with experiment. In the displacive limit of the double-well potential model, the vibration modes, corresponding to a soft phonon of $c-{\mathrm{ZrO}}_2,$ were calculated for each composition of yttria-stabilized zirconia. The effect of anharmonicity yields the fine structure in the spectral density which is associated with stabilization at $x<\mathrm{}10\mathrm{}\mathrm{mol}\%.\mathrm{}$ In studying the phonon dynamics, we use the displacement probability density which quantifies accurately the transition temperature above which the c phase is stabilized.

• Received 11 June 2002

DOI:https://doi.org/10.1103/PhysRevB.66.132105