The sintering temperature effect on the microstructure and dielectric properties of Bi$_4$Ti$_3$O$_{12}$ doped with neodymium

A new set of perovskite-like Bi$_{4-x}$Nd$_x$Ti$_3$O$_{12}$ ($x$ = 0.1, 0.3, 0.5, 0.7) oxides were synthesized by the method of high-temperature solid-phase reaction at the temperatures of 1000$^\circ$C and 1050$^\circ$C. X-ray diffraction study showed that these compounds are single-phase and have the structure of the Aurivillius phases (AP) family with parameters close to the orthorhombic unit cell corresponding to the space group B2cb (41). The microstructure was studied for all obtained Bi$_{4-x}$Nd$_x$Ti$_3$O$_{12}$ ($x$ = 0.1, 0.3, 0.5, 0.7) compositions sintered at temperatures of 1000$^\circ$C and 1050$^\circ$C. Its analysis also showed that the crystallites are similar one of AP family and characterized with a lamellar-like shape. The relative permittivity $\varepsilon/\varepsilon_0$ and the dielectric loss tangent $\operatorname{tg}\delta$ were measured as a function of temperature at frequencies in the range of 100 kHz to 1 MHz.