Phonons and phase transitions in zirconia

Abstract

AbstractThe martensitic‐austenitic phase transition in zirconia was investigated as a function of temperature and pressure using Raman and IR spectroscopy. The frequencies and symmetries of the phonon modes corresponding to the monoclinic (M),C(4 molecules per unit cell) structure were identified at 300 K and 1 atm. The temperatureinduced transition to the tetragonal (TI),Dstructure (2 molecules per unit cell) showed thermal hysteresis (1225 ↔ 1425 K). The corresponding pressure‐induced transition at room temperature showed a pressure hysteresis (3.4 ↔ 3.95 GPa). However, the structural transition was to a different tetragonal modification (TII) withD2horC4vsymmetry with 4 molecules per unit cell.