Model of the polarization response of single-crystal lead magnesium niobate-lead titanate for transducer applications

摘要

A theoretical model is developed and applied to experimentally measured polarization acquired from lead magnesium niobate lead titanite (PMN-PT) single crystals. The model is shown to describe well the polarization behavior with respect to changes in temperature and applied electric field at a variety of levels of applied prestress. Including the effects of prestress is important if the model is to be used in transducer design and output control. Large prestresses are applied to the active materials used in transducers in order to prevent the driver from extending. (Damage to the driver is much more likely should it go into extension during operation, and large applied prestress reduces this possibility.) Physically, the model accounts for both rotation and stretching of elementary dipoles, and realistic values for the elementary dipole moment and dipole concentration are deduced from the measurements using the model. Reasonable dipole behavior with respect to changes in temperature, stress, and electric field is also seen. The model has been shown to successfully interpolate and extrapolate measurements in temperature and electric field at various levels of applied prestress, thus allowing a significant reduction in the number of measurements that must be acquired to characterize single-crystal PMN-PT for transducer applications.