Ferroelectricity has been one of the most used and studied phenomena in both scientific and industrial communities. Properties of ferroelectrics materials make them particularly suitable for a wide range of applications, ranging from sensors and actuators to optical or memory devices. Since the discovery of ferroelectricity in Rochelle Salt (which used to be used since 1665) in 1921 by J. Valasek, numerous applications using such an effect have been developed.