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Raman-active modes and the tetragonal-monoclinic phase transition in ZrO2 doped with 12mol% CeO2

1995; Elsevier BV; Volume: 56; Issue: 7 Linguagem: Inglês

10.1016/0022-3697(95)00027-5

1879-2553

T. Hirata,

Semiconductor materials and devices

For the first time, we present a Raman scattering study of the tetragonal-monoclinic phase transition at low temperature in tetragonal ZrO2-polycrystal doped with 12 mol% CeO2 (Ce-TZP). Raman-active modes of symmetry A1g, B1g and Eg, Ag and Bg for the tetragonal (D4th15;P42nmc) and monoclinic (C2h5;P21c) phases of Ce-TZP, are monitored in the temperature range 76–296 K by Raman scattering. It was found that the 139 cm−1 B1g and the 253 cm −1 Eg modes for the tetragonal phase never disappear, but they coexist with the Raman-active modes for the monoclinic phase after the tetragonal-monoclinic phase transition is induced at 121 K; all Raman-active modes (9Ag + 9Bg) for the monoclinic phase are not detected whereas all Raman-active modes (A1g + 2B1g + 3Eg) for the tetragonal phase are identified. The frequency, linewidth and intensity of each Raman-active mode are determined by Lorenzian-curve fitting to the Raman spectra before and after the phase transition. The 139 cm−1 B1g and the 253 cm−1 Eg modes, and the other Raman-active modes exhibit anomalies at 121 K in the frequency, intensity and linewidth vs temperature plot. The temperature dependence of frequency, linewidth and intensity for the Raman-active modes is discussed, with reference to structural or spectroscopic information on the tetragonal and monoclinic phases of ZrO2 and/or doped ZrO2.