Giant piezodielectric effect near the polymorphic phase boundary of perovskites near resonant frequencies

<h2>Summary</h2> Traditional enhancement of piezoelectric properties via morphotropic phase boundary (MPB) engineering or the incorporation of relaxor ferroelectric (FE) materials faces limitations, including a reduced Curie temperature (<i>T</i>_C) and permittivity saturation. This article introduces a piezodielectric effect that capitalizes on the resonant frequency of common piezoelectric materials with dual-phase coexistence. This approach has yielded an extraordinary permittivity increase exceeding 1,000% at FE–FE phase transition temperature on permittivity-temperature curves. This method of magnifying the FE–FE permittivity shoulder provides a foundation for the precise determination of the MPB position on the phase diagram. In addition, by decoupling permittivity enhancement from <i>T</i>_C reduction, we achieved a colossal relative permittivity (>40,000) and a calculated piezoelectric coefficient (>5,000 pC/N) near room temperature alongside a relatively high <i>T</i>_C (>300°C) in relaxor ferroelectric ceramics. This breakthrough paves the way for amplifying dielectric and piezoelectric properties, offering significant benefits for the performance of transducers and sensors.