Dielectric, ferroelectric, and energy storage properties in dysprosium doped sodium bismuth titanate ceramics

Abstract : In this work, Na-0.5(Bi1-xDYx)(0.5)TiO3 (0 <= x <= 15%) ceramics were prepared via solid state reaction method and were characterized. A stable and pure perovskite phase was revealed by X-ray diffraction analysis for all compositions and a symmetry change from rhombohedral to orthorhombic phase was detected beyond 10% of Dy substitution. The incorporation of Dy3+ into Sodium Bismuth Titanate (Na0.5Bi0.5TiO3) matrix allows a substantial decrease of the coercive field, an increase in the resistivity, and leads to a high stability of the dielectric permittivity (Delta epsilon/epsilon((150) (degrees C)) <= +/- 15%) over a wide temperature range. Furthermore, this system was found to exhibit improved energy storage properties at high temperatures with a maximum energy density of 1.2 J/cm(3) obtained for 2%Dy composition at 200 degrees C. The obtained results are very promising for energy storage capacitors operating at high temperatures.