Phase diagrams of single-domain ferroelectric-dielectric superlattices

Using the thermodynamic theory, the authors developed misfit strain-temperature phase diagrams of single-domain ferroelectric-dielectric superlattices grown on cubic substrates. Owing to internal electric fields appearing in such multilayers, the superlattice diagrams are expected to be very different from phase maps of homogeneous ferroelectric films. The calculations show, however, that this electrostatic effect does not change relative positions of phase transition lines. It only shifts the diagram as a whole along the line separating stability ranges of paraelectric phase and in-plane polarization state. The magnitude of this shift is governed by the capacitance of dielectric layer and the thickness of ferroelectric one. (c) 2007 American Institute of Physics.