文摘
In order to improve the piezoelectric properties of ferroelectric materials, an optimization based method is developed to identify the topology of the piezoelectric material in the unit cell. A mathematical model is first established to identify the relationship between the piezoelectricity and some observable or measurable parameters in the unit cell. As for single crystal, the noncollinear polarization angles are chosen as the optimization variables. While for polycrystalline materials, the orientations of the grain are chosen as the optimization variables, which falling in a Gaussian distribution after poling. Since it is impossible to analyze all possible combinations of the distribution parameters or the angles, the differential evolution (DE) is applied to solve the proposed optimization model as a widely used global optimization method. Numerical experiments are carried out in Pb(Mg1/3Nb2/3)O3–PbTiO3(PMN–PT) for both single crystals and polycrystalline materials. A good agreement is achieved with the published data in single crystals, and the distribution parameters with enhanced piezoelectric properties are obtained for crystals. This study provides a fundamental perspective to enhance the piezoelectricity by designing of microscopic crystal morphology.