Ferroelectric Domains and Incommensuration in the Intermediate Phase Region of Lead Zirconate

Electron microscopy of lead zirconate (PbZrO 3 ) identified the presence of an intermediate region between the high‐temperature cubic state and the low‐temperature antiferro‐electric state. Ferroelectric domains were found to occur between 200° and 230°C on cooling. Convergent‐beam electron diffraction studies identified rhombohedral symmetry for the ferroelectric phase. Selected area electron diffraction patterns determined ½{110} superlattice reflections in the ferroelectric state. The reflections were associated with a softening of an M‐type oxygen octahedral rotation mode. In addition, 1/x{110} incommensurate superlattice reflections were detected within a narrow temperature range for PbZrO 3 between the intermediate ferroelectric and low‐temperature antiferroelectric states.