Relaxor ferroelectric single crystals such as PMN-PT and PIN-PMN-PT undergo field driven phase transformations when electrically or mechanically loaded in crystallographic directions that provide a positive driving force for the transformation. The observed behavior in certain compositions is a phase transformation distributed over a range of field levels without a distinct forward or reverse coercive field. This work focuses on the material behavior that is observed when the crystals are loaded sufficiently to drive a partial transformation and then unloaded as might occur when driving a transducer to achieve high power levels. A set of experiments was conducted to characterize the minor hysteresis loops that occur with the partial transformations. Distributed transformations have been modeled using a Gaussian distribution of transformation thresholds. In this work the Gaussian model is extended to include the partial transformations that occur when the field is reversed before the transformation is complete. The resulting minor hysteresis loops produced by the model are in good agreement with the experimental results.

This content is only available via PDF.
You do not currently have access to this content.