Direct Electric-Field Induced Phase Transformation in Paraelectric Zirconia via Electrical Susceptibility Mismatch.

Electric field driven phase transformations require two phases with a mismatch in their electric polarization, as seen in antiferroelectric-to-ferroelectric transformations, where the ferroelectric phase has a permanent polarization that is favored under field. Many other nonferroelectric dielectric materials can become electrically polarized according to their electrical susceptibility, yet such induced polarizations are not generally considered capable of enabling a phase transformation. Here we explore a susceptibility-mismatch phase transformation in a paraelectric ceramic, yttria-doped zirconia. Using in situ x-ray diffraction at 550 °C we show that the monoclinic-to-tetragonal transformation can be driven directly by an electric field, providing experimental evidence of a paraelectric-to-paraelectric phase transformation. Considering the ∼1% mechanical strain of this transformation, the resulting electromechanical coupling may have potential for solid-state electrical actuators.