Internal fielda and ferroelectric ordering in potassium ferrocyanide trihydrate.

Abstract

On the basis of the existing experimental data it is assumed that the mechanism responsible for the ferroelectric transition of potassium ferrocyanide trihydrate is a rotational reorientation of the water molecules. Accordingly, the electrostatic energy of the water molecules (approximated by three point charges) is calculated as a function of their orientation. The low temperature configuration is obtained by minimising the electrostatic energy. A possible model is then proposed for the ferroelectric to paraelectric transition, consisting in the switching of the water molecules between two energetically equivalent configurations. The results are in good agreement with the experimental data.