2-DIMENSIONALLY PERIODIC DOMAIN-STRUCTURE OF A FERROELECTRIC INCLUSION IN A MATRIX

An equilibrium domain structure is predicted for a ferroelectric inclu sion interacting elastically with a paraelectric matrix in the case of a phase transition from a cubic to a tetragonal phase. This is a two- dimensionally periodic structure of domains in the shape of slabs of r ectangular cross section elongated along the [110] direction. The incl usion contains four types of ferroelectric domains. All the domain wal ls are neutral and represent invariant planes free of elastic stresses . Calculations are reported of the periods of the domain structure, go verned by the competition between the energy of domain walls and the e nergy of electric and elastic fields penetrating the matrix surroundin g the inclusion.