Dielectric and Ferroelectric Response of Multiphase Bi‐Fe‐O Ceramics

The structural, dielectric, and ferroelectric characterization of multiphase Bi‐Fe‐O prepared with an excess of Bi up to 20% is reported. It is found that the dominant phase in all samples is the BiFeO3perovskite in addition to an increasing amount of the Bi‐rich sillenite phases (Bi12.5Fe0.5O19.48/Bi25FeO39) with the Bi excess content. At room temperature, the multiphase Bi‐Fe‐O results in advanced electrical properties, with higher dielectric constant (161 at 1 MHz) and low losses (tanδ = 0.032 at 1 MHz). The ferroelectric character of multiphase ceramics is confirmed by PUND measurements, which shows increased polarization values and coercive field with respect to the single phase ceramics. Multiphase Bi‐Fe‐O ceramicsprepared with Bi excess (up to 20%) are morphologically, structurally, dielectrically, and ferroelectrically investigated. Improved dielectric and ferroelectric properties are observed in the multiphase samples with respect to the single phase bismuth ferrite and further insight on the effect of microstructure on the ceramics dielectric properties is achieved.