Crystal structure and dielectric properties of layered perovskite-like solid solutions Bi_(3-x)Gd_(x)TiTaO_(9)(x=0.0,0.1,0.2,0.3)with high Curie temperature

The Aurivillius phases[Bi_(2)O_(2)][A_(n−1)B_(n)O3_(n+1)]are well-known ferroelectrics with high Curie temperatures T_(C).High-temperature piezoceramics Bi_(3-x)Gd_(x)TiTaO_(9)(BGdTTa,x=0.0,0.1,0.2,0.3)were prepared by a solid-state reaction method.The structural and electrophysical characteristics of BGdTTa 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 Aurivillius phases(m=2)with the orthorhombic crystal lattice(space group A2_(1)am).The temperature dependence of the relative permittivity ε/ε_(o)(T)of the compounds was measured and showed that the Curie temperature T_(C) of perovskite-like oxides Bi_(3-x)Gd_(x)TiTaO_(9)increases linearly with an increase in the substitution parameter x to TC=925℃.The activation energies of charge carriers have been found in different temperature ranges.