IMF2017

Ferroelectric properties of BaTiO₃ (BTO) nano-materials, especially the possible existence of ferroelectric critical size, are extensively studied for the use in devices of nanoscale memory storage and integrated microelectronics. Approaching the estimated ferroelectric critical size (2.5–3.6 nm), we first report the presence of ferroelectricity on BTO nanocrystal assemblies with an average crystal size of from 4.5 nm down to 2.8 nm. Crystal structure analyses based on atomic distribution function (PDF) revealed good structural coherence and confirmed the non-centrosymmetric phase structure of these nanocrystals at room temperature. With increase of the temperature, declined ferroelectric features and responses are observed by Raman scattering and second harmonic generation (SGH), indicating a quite diffuse phase transition of the nanocrystals. After self-assembled into a compact thin film, selectively written and read electric polarization of the nanocrystals shows direct evidence for the presence of ferroelectricity, which provides theoretical supports for the high-density ferroelectric memories. Owing to the remarkable ferroelectric properties, these nanocrystals are prospective to be used in various devices and offer promising candidates for the future printing electronic applications.