Structural change and some associated anomalies in the ferroelectric PbK₂LiNb₅O₁₅

Abstract

The knowledge of the structural change occurring between the ferroelectric and paraelectric phases in the newly discovered PbK₂LiNb₅O₁₅ is improved by means of X-ray diffraction, TEM, DSC, and dielectric constant studies. The room temperature phase is of Pba2 symmetry, which confirms the ferroelectric and ferroelastic nature of the structural change. It is shown that the transition between the tetragonal phase at high temperature and the Pba2 phase occurs via some intermediate phase(s) and that its mechanism is complex.

Key Words:

• phase transition
• ferroelectric
• ferroelastic
• structure
• domains