Combining Experiments and Modeling to Characterize New Compositions of Relaxor Ferroelectric Single Crystals

Field induced phase transformations in relaxor ferroelectric single crystals with compositions near the morphotropic phase boundary can be induced by electrical or mechanical loading above a certain threshold. Concurrent electrical and mechanical loading of [011]_C cut and poled crystals drives the ferroelectric rhombohedral to ferroelectric orthorhombic phase transformation at lower threshold levels than either load alone. Likewise, electrical loading of [001]_C cut and poled crystals hinders the mechanically driven ferroelectric rhombohedral to ferroelectric orthorhombic phase transformation. The current experimental technique for characterization of the large field behavior including the phase transformation requires an extensive set of measurements performed under electric field cycling at different stress preloads and stress cycling at different bias electric fields, repeated at multiple temperatures. This procedure requires specialized equipment and training, and is very time-consuming. In this work a mechanism based model is combined with a more limited set of experiments to obtain the same results. The model utilizes a work-energy criterion that calculates the work required to induce the transformation by overcoming an energy barrier. This approach reduces the number of required experiments while potentially eliminating the need of a load frame for mechanical loading of [011]_C crystals. This decreases the time and resources required for characterization of new compositions. The results of the combined experiment / modeling approach are compared to the fully experimental approach and error is discussed.