Preparation and dielectric and piezoelectric properties of Bi3TiNbO9, Bi2CaNb2O9, and Bi2.5Na0.5Nb2O9 ceramics doped with various elements

Ceramic samples of the Aurivillius phases Bi3TiNbO9, Bi2CaNb2O9 and Bi2.5Na0.5Nb2O9 doped with a variety of elements have been prepared by hot pressing. The ceramics have been characterized by X-ray diffraction and their dielectric and piezoelectric properties have been studied. The temperature dependences of their dielectric permittivity, dielectric loss tangent, and piezoelectric response have been investigated at temperatures from 290 to 1250 K and frequencies from 25 Hz to 1 MHz. The samples have been shown to possess ferroelectric properties with a Curie temperature in the range 1060–1210 K. The piezoelectric charge coefficient d 33 of poled ceramic samples is 11–18 pC/N at room temperature and remains unchanged up to 800 K.