Electric field induced polarization rotation in squaric acid crystals revisited

TL;DR

This study revisits the electric field induced polarization rotation in squaric acid crystals using an alternative model, confirming its validity through comparison with experimental data and analyzing phase diagrams and polarization curves.

Contribution

It introduces an alternative parameter set for the model of squaric acid crystals and validates its effectiveness against experimental data.

Findings

The alternative model parameters are consistent with experimental data.

No significant advantage of the new parameters over previous ones.

Phase diagrams and polarization curves are accurately reproduced.

Abstract

Using the previously developed model we revisit the problem of the electric field induced polarization rotation in antiferroelectric crystals of squaric acid. We test an alternative set of the model parameters, according to which the dipole moments associated with the H$_2$C$_4$O$_4$ groups are assumed to be parallel to the diagonals of the $ac$ plane. The $T$-$E$ phase diagrams and the polarization curves $P(E)$ for the fields directed along the $a$ axis and along one of the diagonals are considered. Comparison of the theoretical results with the newly published experimental data confirm the validity of the model. The calculations reveal no apparent advantage of the new set of the parameters over the previously used set.