Bending-Induced Giant Polarization in Ferroelectric MEMS Diaphragm

Zhihong Wang, Weiguang Zhu

    Research output: Chapter in Book/Report/Conference proceedingChapter

    Abstract

    The polarization induced by the strain gradient, i.e. the flexoelectric effect, has been observed in a micromachined Pb(Zr0.52Ti0.48)O3 (PZT) diaphragms. Applying air pressure to bend a flat diaphragm which initially does not exhibit any electromechanical coupling can induce a resonance peak in its impedance spectrum. This result supposes that bending, thus the strain gradient in the diaphragm causes polarization in PZT film. We also investigated the switching behaviors of the polarization in response to an external electric field in a bent diaphragm and further quantified the polarization induced by the strain gradient. The effective flexoelectric coefficient of the PZT film has been calculated as large as 2.0 × 10−4 C/m. A giant flexoelectric polarization of the order of 1 μC/cm2 was characterized which is of the same order of magnitude as the normal remnant ferroelectric polarization of PZT film. The suggested explanation for the giant polarization is the large strain gradient in the diaphragm and the strain gradient induced reorientation of the polar nanodomains.
    Original languageEnglish (US)
    Title of host publicationFlexoelectricity in Solids
    PublisherWorld Scientific Pub Co Pte Lt
    Pages337-365
    Number of pages29
    ISBN (Print)9789814719315
    DOIs
    StatePublished - Sep 9 2016

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