  We propose an order-disorder type microscopic model for BaTiO$_3$-like
Ferroelectric Substance. Our model has three phase transitions and four phases.
The symmetry and directions of the polarizations of the ordered phases agree
with the experimental results of BaTiO$_3$. The intermediate phases in our
model are known as an incompletely ordered phase, which appears in a
generalized clock model.

Statistical Mechanics;Materials Science