Structure and Dielectric Properties of Solid Solutions Bi_(4+x)Sr_(2-x)Ti_xTa_(4-x)O_(18) (x= 0.0, 0.5, 1.0, 1.5, 2.0)

摘要

The structure and dielectric properties of a numbers of layered perovskite-like of Bi4+xSr2-xTixTa4-xO18 (x= 0.0, 0.5, 1.0, 1.5, 2.0) oxides with the APs structure have been studied. The temperature dependences of the relative permittivity ε/ε_0(T) and tangents to the tangential dielectric losses tan δ have been measured. Single-phase and space groups (A21 am, Z= 36) of the Aurivillius phases (m= 2) have been determined from X-ray powder diffraction data. The relationship between crystal lattice distortions (parameters a, b, c) and the chemical composition of synthesized compounds have been established. The temperature of the second-order phase transition from the paraelectric state to the ferroelectric state varies with the parameter x, respectively. The activation energies have been calculated.