Temperature dependence of Raman scattering in stabilized cubic zirconia

The temperature dependence of Raman spectra of cubic yttria-stabilized zirconia (YSZ) for three yttria concentrations (10, 15, and 20 wt %) is investigated in the range 40--1470 K. The variation of the spectra with temperature implies that first-order scattering (one-phonon processes) is dominant in this material, providing further evidence that the broad features observed in the spectra are caused mainly by partial lattice disorder rather than by combination (higher-order) processes. The high-temperature phase of YSZ is entirely stable in this range and remains cubic throughout. The temperature-induced frequency shifts of the band at {~}600 cm^-1 (attributed to the F2g zone-center optic mode) are determined for the three different yttria concentrations. Furthermore, using uniaxial stress data as well, the volume contribution to such shifts is calculated and compared to the lattice anharmonicity contribution. It is found that the volume contribution is larger than the total effect (by a factor of about 2) for all three compositions at 300 K, implying that the bonding in cubic YSZ has ionic character.