Natural-superlattice structured CaBi2Nb2O9-Bi4Ti3O12 ferroelectric thin films

Natural-superlattice-structured/intergrowth CaBi2Nb2O9-Bi4Ti3O12 (CBNO-BIT) ferroelectric thin films were successfully prepared via a magnetron sputtering process. XRD and TEM analysis revealed the [Bi2O2-(CaNb2O7)-Bi2O2-(Bi2Ti3O10)]n intergrowth structure of the film, as well as a (200)/(020) texture. XPS and EDS results confirmed that the film composition is close to the chemical stoichiometry. With its microstructure being successfully tailored at the nanoscale, the CBNO-BIT film exhibits good electrical properties, including a large dielectric constant (εr ∼390), a high piezoelectric coefficient (d33 ∼90 pm/V) as well as a high energy storage density (WE ∼76 J/cm3). Finally, the intergrowth nature of the film was verified by the measured temperature-dependent dielectric response (C-T).