LAUSR

Interface strain significantly affects polarization in ferroelectric devices. In this paper, an innovative strategy is proposed to substantially enhance ferroelectric polarization using an ultra‐thin “soft‐buffer‐layer” (SBL), which reduces dislocation density and increases the tetragonality of ferroelectric thin films because of small elastic constants of Ti3Al along x and y axes. And in this work, it is demonstrated that PbZr0.4Ti0.6O3 (PZT) thin films are perfect c‐axis‐oriented epitaxial structures on (001) SrTiO3 (STO) substrates. The PZT capacitor with Ti3Al buffer layer exhibits a remarkable remnant polarization, reaching up to 131.93 µC cm−2 at an applied voltage of 5.00 V. Surprisingly, under the clamping effect of SrRuO3 and STO, Ti3Al films exhibit cubic structure and facilitate matching to the PZT film. It is proposed that the introduction of the Ti3Al buffer layer notably improves the tetragonality (c/a) ratio from 1.002 to 1.024, and significantly enhancing the polarization. There is no doubt that this adjustment reduces dislocation density and decreases stress influence from STO substrate. Given these advantages, the SBL method presents a compelling option for epitaxial PZT films, and also for enhancing the physical properties of other functional thin film materials.