Pyroelectric Materials

A pyroelectric material characteristically develops an electric polarization as its temperature is changed. The magnitude of the polarization generated per unit area is less in a polycrystalline sample for a given temperature interval than in a single crystal, but is maximized if the crystallites are fully ordered along the polar direction. All pyroelectric crystals are necessarily piezoelectric (see Piezoelectric Materials); some pyroelectrics are also ferroelectric (see Ferroelectric Materials). Pyroelectric materials are used in a variety of devices, including infrared detectors and television cameras.