The ferroelectric phase transition in small spherical particles

The ferroelectric phase transition in a small particle depends on its size. Analytical results concerning the size dependence of the transition temperature, and the polarization profile in the ferroelectric phase have been obtained within a phenomenological model, which has been previously studied only numerically. The model does not take into consideration the depolarization held, assuming full compensation of surface charges. The dynamic susceptibility deviates from Debye-like behaviour in exhibiting a broadening at higher frequencies. The static susceptibility obeys the Curie-Weiss law, and exhibits a similar divergency at the point of the size-driven transition.