Microstructure and texture dependence of the dielectric anomalies and dc conductivity of $Bi3TiNbO9$ ferroelectric ceramics Available to Purchase

Ceramics of composition $Bi3TiNbO9$ (BTN) and perovskite-layered structure (Aurivillius type) [B. Aurivillius, Ark. Kemi 1, 463 (1949)] were processed by natural sintering and hot pressing from amorphous precursors. Precursors were obtained by mechanochemical activation of stoichiometric mixtures of oxides. These materials are in general interesting for their use as high-temperature piezoelectrics. Among them, BTN possesses the highest ferroparaelectric phase-transition temperature $(>900°C)$⁠. The transition temperature establishes the working limit of the ceramic and the electric properties, especially the dc conductivity, affect on its polarizability. In this work, dielectric studies of BTN ceramics with controlled texture and microstructure have been made at 1, $100KHz$⁠, and $1MHZ$ and in the temperature range from $200°C$ up to the ferroparaelectric transition temperature. Values of $ε′∼250$ at $200°C$ are achieved in ceramics hot pressed at temperatures as low as $700°C$ for $1h$⁠.