The high-pressure phase sequence in nanocrystalline zirconia

Abstract

X-ray diffraction and Raman data on the pressure induced phase transitions of a nanometric zirconia, ZrO2, are analyzed via a classical phenomenological Landau approach of the bulk. It is concluded that the initial tetragonal structure (D 4h15), which is a metastable bulk state of zirconia at ambient conditions, evolves continuously towards the ideal cubic fluorite structure (O h5) via an intermediate tetragonal form (D 4h14). The proposed phenomenological model describes consistently all experimental peculiarities, including the hybridization and softening of the low-frequency Raman active modes along with lattice-parameter anomalies. © EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2003.