Enhancement of dielectric and ferroelectric properties by addition of Pt particles to a PZT matrix

Ferroelectric/metal composites have been characterized for their electric field dependence of the dielectric and ferroelectric properties. The composites show an interesting change of dielectric properties with increasing metal concentration. A relatively high dielectric constant, up to four times as high as that of monolithic lead zirconate titanate (PZT), is observed in the investigated composition range. The dielectric properties are clearly electric field dependent. The tunability of the composite, defined as the difference between the dielectric constant with no applied voltage and the dielectric constant with an applied voltage, divided by the dielectric constant with no applied voltage, was found to be ∼ 17, whilst for the monolithic PZT ceramics it is about 3 only. This offers perspectives for application of these composites in lighting electronics and voltage controllers. Ferroelectric hysteresis measurements on these composites revealed a square-shaped hysteresis loop with remnant polarization comparable with single PZT ceramics, while the coercive field was much lower than that of pure PZT ceramics. This might be interesting for application of these composites as a ferroelectric memory material with decreased switching voltage.