Dielectric properties and phase transition in SrBi2Nb2O9–SrBi2Ta2O9 solid solution

Structural and dielectric properties of SrBi2(Nb1−xTax)2O9 solid solution, (SBNT), with x = 0.0, 0.1, 0.2, 0.3, 0.5, 0.7, 1.0 were investigated. Crystal structure at room temperature was analyzed by X-ray diffraction study. SBNT exhibits an Aurivillius structure and the c lattice constant decreases with increasing concentration of Ta in the solution. The studies of real (ɛ′) and imaginary (ɛ″) parts of permittivity as a function of temperature (20–500 °C) and frequency (0.1–100 kHz) were carried out, as well. The anomalies of ɛ′(T) and ɛ″(T) associated with phase transition from the tetragonal paraelectric phase (PT) to the orthorhombic ferroelectric phase (FO) were observed. They are strongly dependent on the Ta content in the solution. The grain structure and chemical composition were examined by a scanning electron microscope (SEM), with an energy dispersion spectrometer (EDS). The EDS analysis indicated a homogeneous distribution of all elements of ceramics within the grains.