1. Piezoelectric actuators

1.1 Basic principle

This first family of actuators exploits the inverse piezoelectric effect, identified by the Curie brothers in the 1880s. This effect enables mechanical deformation to be generated in a material by applying an electric field. A wide range of materials can be used to achieve this effect, including quartz and ceramics with perovskite or tungsten-bronze crystalline structures. For actuation, ferroelectric ceramics are widely preferred, in particular lead titano-zirconate (hereinafter conventionally referred to as PZT), and possibly lead titanate PbTiO3 or barium titanate BaTiO3. A semi-crystalline polymer such as PVDF also exhibits a piezoelectric effect, but its use as an actuator remains very limited.

Ferroelectric ceramics such as PZT are...