Dielectric relaxation and relaxor behavior of ferroelectric 0.8PbFe0.5Ta0.5O3-0.2PbTiO3 ceramics

(1 - x)PbFe0.5Ta0.5O3 (PFT)-xPbTiO(3) (PT) solid solution systems (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) were prepared by a solid-state reaction method. With increasing PbTiO3 content, the ferroelectric-paraelectric phase transition temperature, T-c, increased linearly, and the corresponding dielectric properties changed from a relaxor ferroelectric with a diffuse phase transition to a normal ferroelectric with a sharp dielectric peak. The dielectric properties of the 0.8PFT-0.2PT ceramics with x = 0.2 show a relaxor behavior at T-c = 64 degrees C, which is higher than that for the PFT ceramics with T-c = -24 degrees C. The ferroelectric P-E hysteresis loops of the 0.8PFT-0.2PT ceramics still remain above the phase transition temperature, due to the existence of polar microregions. The dielectric properties and P-E hysteresis loops of the 0.8PFT-0.2PT ceramics are investigated and explained. by the ferroelectric relaxor behaviors.