Dielectric properties of (Na0.5Bi0.5)(1-x)Me(x)TiO3 ceramics near morphotropic phase boundary

• Published in: Journal of materials science Vol. 36; no. 8; pp. 1981 - 1985
• Main Authors: Suchanicz, J, Kus, Cz, Gavshin, M G, Kudzin, A Yu
• Format: Journal Article
• Language: English
• Published: 15.04.2001
• ISSN: 0022-2461

Ceramic samples of modified ferroelectric sodium-bismuth titanate (Na0.5Bi0.5)0.87Me0.13TiO3 (Me = Pb, Sr and Pb+Sr) were prepared using conventional solid state reaction techniques. The studies of powder X-ray diffraction of the obtained compounds revealed their rhombohedral symmetry at room temperature, the increase of lattice constant, and the increase of rhombohedral lattice distortion (except for the material with Sr dopant, where distortion decreases). Temperature (room temperature to 400 C) and frequency (20 Hz to 1 MHz) dielectric measurements reveal that A-site cations addition of Pb and/or Sr have resulted in an increase of relative electric permittivity. However, the temperature Tm (when the electric permittivity is a maximum) increases after Pb or Sr doping and decreases after (Pb+ Sr) doping. The pyroelectric and current loop measurements have shown that all samples were ferroelectric. The results of these measurements also allowed us to determine the temperature variation of the remanent and spontaneous polarizations. The polarizations are found to decrease after Pb or Sr doping and increase after (Pb+Sr) doping. The piezoelectric constants (d33 and d31) and electromechanical coupling factors (k33 and k31) were obtained from resonance-antiresonance measurements method. (Author)