Thermodynamic and phase-field studies of phase transitions, domain structures, and switching for Ba(Zr_xTi_{1− x})O₃ solid solutions

While extensive experimental activities have been carried out to study the phase transitions and ferroelectric properties of BaZr_xTi_{1- x}O₃ solid solutions, the corresponding theoretical understanding is largely lacking due to the unavailability of thermodynamic potentials for this system. In this work, an eighth-order polynomial of thermodynamic potential for BaZr_xTi_{1- x}O₃ (x≤0.3) solid solutions is established based on the existing potential coefficients of BaTiO₃ and theexperimentally measured phase diagram of BaZr_xTi_{1- x}O₃ solid solutions. It is then employed to predict and understand the domain structures and switching for BaZr_xTi_{1- x}O₃ (x ≤0.3) single crystals using phase-field simulations. The simulated domain structures and switching are consistent with thermodynamic analysis and available experimental measurements, validating the established thermodynamic potential. It is expected that this thermodynamic potential will find wide applications to studying the phase transitions and ferroelectric properties of BaZr_xTi_{1- x}O₃ (x ≤0.3) bulk and nanoscale materials.