Bridging domain mechanism for phase coexistence in morphotropic phase boundary ferroelectrics

Computer modeling and simulation reveals a bridging domain mechanism that explains the phase coexistence commonly observed around the morphotropic phase boundaries of ferroelectric solid solutions. The simulation takes into account the important role of coupled ferroelectric and ferroelastic domain microstructures in phase coexistence phenomenon. It shows that minor domains of metastable phase spontaneously coexist with and bridge major domains of stable phase to reduce total system free energy, including bulk free energy, domain wall energy, and long-range electrostatic and elastostatic energies. The existence of bridging domains also explains the enhanced piezoelectric response in the vicinity of morphotropic phase boundaries. (C) 2007 American Institute of Physics.