Dielectric and ferroelectric properties of 0.82K0.5Bi0.5TiO3-0.18PbTiO3 ceramic: effect of uniaxial pressure

0.82K0.5Bi0.5TiO3-0.18PbTiO3 ceramic was fabricated by the mixed oxide method. An X-ray study shows that the obtained ceramic has a pure perovskite structure. The ϵ(T) and tanδ(T) show a peak centered at about 468 °C and 421 °C, respectively, and related to the tetragonal–cubic phase transition. The effect of uniaxial pressure (0–1500 bar) on dielectric and ferroelectric behavior of this ceramic was investigated. It was shown that uniaxial pressure significantly influences these properties. With the increasing pressure, (1) the maximum value of the electric permittivity and dielectric losses tanδ decreases and increases, respectively, (2) the peaks of ϵ and tanδ shift to higher temperatures, (3) the permittivity characteristics are smeared and the thermal hysteresis decreases, (4) hysteresis loops are smeared. The results were interpreted in term of domains (domains walls) change and de-aging process under the action of uniaxial pressure.