A Study of Structural Phase Transitions in Antiferroelectric PbZrO3 by Neutron Diffraction

Abstract

Temperature dependence of neutron diffraction intensities of PbZrO 3 was measured in the room-temperature antiferroelectric phase. Intensities of strong superlattice reflections with wave vectors q Σ ≡(1/4 1/4 0) and q R ≡(1/2 1/2 1/2) show different temperature dependence each other. Intensities of weak superlattice reflections with q P ≡(1/4 1/4 1/2)= q Σ + q R and products of intensities of reflections with q Σ and q R show the same temperature dependence. The crystal structure previously determined by Fujishita et al. [ref. 4] was reexamined; the structure was found to be described by a sum of modulations associated with lattice vibrational modes Σ 3 , R 25 x and R 25 y . Successive phase transitions concerning these modulations were observed at 233°C and at around 235°C on heating, and at around 235°C and at 228°C on cooling. Because the modulation with q R is associated with mode R 25 , another antiferroelectric structural modulation which exists only in the intermediate antiferroelectric phase is r...