The first widespread ferroelectric ceramics material, which had ferroelectric properties not only in the form of a single crystal, but in the polycrystalline state, i.e. in the form of ceramic barium titanate was BaO•TiO2, which is important now.
A significant nonlinearity of capacitance capacitor having ferroelectric ceramics materials, so-called varikondy, types of VC-1 VC-2, VC-3 and others.
Ferroelectric ceramics are used in capacitors, sensors, actuators, non-volatile memory, and medical devices due to their ability to maintain and reverse electric polarization.
[1] Due to their piezoelectric and pyroelectric properties, they are also used in energy harvesting, infrared detectors, and ultrasonic transducers.
Additionally, they are employed in RF filters, electro-optic devices, and various energy-efficient applications.