Para-ferro phase coexistence in DKDP crystals

Abstract

The coexistence between the paraelectric (paraelastic) and the ferroelectric (ferroelastic) phases in DKDP crystals near 215 K is an interesting example of competition between chemical, electrostatical and mechanical energies. Without applied electric field or stress, the phase front shapes in different thermal conditions are experimentally observed and explained. The domain texture in the ferroelectric region appears as quasi monodomain during the phase coexistence in particular situations. The dielectric constant is demonstrated as the sum of three contributions: a monodomain one, a polydomain one and another due to the existence of the phase front in the sample.

Key Words:

• Phase transitions
• solid-solid interfaces
• domains
• electric permittivity