Electrical properties of non-stoichiometric PZT 95/5 ferroelectric ceramics

Pb-0.99(Zr0.95Ti0.05)(0.98)Nb0.02O3 (denoted as PZT 95/5) ceramics were prepared according to the nominal composition of Pb0.99+x (Zr0.95Ti0.05)(0.98)Nb0.02O3+x (-0.01 a parts per thousand currency sign x a parts per thousand currency sign 0.04). The electrical properties as a function of lead oxide (Pb) stoichiometry were evaluated. X-ray diffraction analysis shows that all the as-synthesized PZT 95/5 powders are pure perovskite phase and the unit cell volume increases with the addition of Pb. SEM micrographs indicate the fracture mode tends to be predominately intergranular and grain size gets bigger with the increase of Pb content. The coercive field decreases with the increase of Pb till x = 0.02 and then increases when the excess Pb is over x = 0.02. The remnant polarization first increases and then decreases with the increasing amount of excess Pb. Sample with excess Pb x = 0.03 has the biggest value of remnant polarization.