Crystal structure and dielectric properties of layered perovskite-like solid solutions Bi3−xGdxTiNbO9 (x=0, 0.1, 0.2, 0.3) with high Curie temperature.

The Aurivillius phases (APs) [Bi₂O₂] 2 + [ A m − 1 B m O 3 m + 1 ] 2 − are well-known ferroelectrics with high Curie temperatures. High-temperature piezoceramics Bi 3 − x Gd_xTiNbO₉(BiGdTiNb, x = 0 , 0.1, 0.2, 0.3) were prepared by a solid-state reaction method. The structural and electrophysical characteristics of BiGdTiNb ceramics have been studied. According to the data of powder X-ray diffraction, all the compounds are single-phase with the structures of two-layer APs (m = 2) with the orthorhombic crystal lattice (space group A 2 1 a m). The temperature dependence of the relative permittivity ε ∕ ε 0 (T) of the compounds was measured and showed that the Curie temperature of perovskite-like oxides Bi 3 − x Gd_xTiNbO₉ increases linearly with an increase in the substitution parameter x to T C = 9 5 0 ∘ C. The activation energies of charge carriers have been found in different temperature ranges. [ABSTRACT FROM AUTHOR]