Negative Piezoelectric Effect in Quasi-2d Hybrid Improper Ferroelectric Sr3zr2o7 Ceramics with Enhanced Ferroelectric Properties

Abstract

Hybrid Improper Ferroelectrics with Ruddlesden-Popper structure recently have attracted much attention, due to their inherent ferroelectric mechanism and special physical properties. However, these materials often exhibit low remnant polarization and high coercive fields, and limited testing of their piezoelectric properties. Enhancing remnant polarization and reducing coercive fields remain significant challenges, accurately measuring the piezoelectric coefficients could also provide valuable insights. This study investigates the effects of 9% excess SrO on the crystal structure and electric properties of quasi-two-dimensional Sr3Zr2O7 ceramics. It is found that addition of SrO could effectively decrease the content of impurity phase of SrZrO3, and obviously increase the remnant polarization and dramatically reduce the coercive field. Using the high-purity Sr3Zr2O7, the piezoelectric coefficient, optical band gap and leakage current were probed to be -66.7 pm/V, 5.18 eV and 10-7 A/cm2, respectively. At the same time, first principle calculation is performed to investigate the polarization, piezoelectric properties, energy band gap and phonon property of Sr3Zr2O7. Our study demonstrates that compositional tuning proves to be an effective strategy for modulating coercive fields and polarization in Sr3Zr2O7 ceramics, offering a new approach to improving the ferroelectric performance of Ruddlesden-Popper structure Hybrid Improper Ferroelectrics.

Keywords: Ferroelectric material, Coercive field, Band gap, Absorption spectra