Electrically driven antiferroelectric-ferroelectric phase transition in thin films studied by in situ synchrotron x-ray diffraction
Phys. Rev. Materials 10, 014405 – Published 15 January, 2026
DOI: https://doi.org/10.1103/w6fz-psgb
Abstract
Electric-field-induced phase transitions are the most important characteristics of antiferroelectric materials, furnishing them with rich functional properties. While they are actively studied for their potential applications such as high-strain transducers and electrocaloric devices, the applied electric field needed to reach the polar phase makes structural studies throughout the full transition of utmost importance. Here, the evolution of both structure and strain in antiferroelectric thin films was investigated by in situ synchrotron x-ray diffraction during electrical actuation up to 700 kV/cm applied DC electric field. The ferroelectric phase, characterized by its polar order and resulting piezoelectric activity, was found to nucleate at an electric field of 200 kV/cm and to disappear below 160 kV/cm, showing a hysteretic behavior. The variation of the different Bragg peak widths of antiferroelectric and ferroelectric phases revealed the variation of strain distributions in the thin film where antiferroelectric and polar regions coexist during the phase transformation. In addition, the effective longitudinal piezoelectric coefficient of the ferroelectric phase itself, which remains inaccessible by classical macroscopic interferometric measurements, was determined for the first time and reached a value of 67 pm/V, which is quite significant for a thin film clamped on a substrate. These findings provide a clearer understanding of the dynamics of the electric-field-induced phase transition in antiferroelectric thin films.
