Study of of 77 nm thick single crystal ferroelectric capacitors showing that the intrinsic response is exactly that of bulk.
Stoichiometry, doping, defect chemistry and also ceramic microstructure often control ferroelectric properties in bulk materials.
The family of ferroelectric ceramic materials such as barium titanate and lead zirconate titanate (PZT) were developed in the 1940s.
All pyroelectric crystals are necessarily piezoelectric, with some also being ferroelectric.
By applying a bias voltage across the capacitors, an electric field is set up within the ferroelectric, causing its permitivity to change.