  Phase field modeling of domain structures in ferroelectrics nanorods of
different shape and sizes is presented. The vortex domain configurations in
confined ferroelectrics have been explored by varying the ratio of the energies
of electrostatic and elastic interactions. It is shown that a strong effect of
the electrostatic interactions can cause the formation of 90o domain walls that
do not satisfy the condition of strain compatibility. A good agreement between
the results of phase field modeling and the results of atomistic calculations
for nano ferroelectrics demonstrates that the phase field approach provides an
effective tool for the analysis of domain structures in nano-ferroelectrics.
