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Pyroelectricity is the phenomenon that the charges appear on the surface of certain materials when they are heated or cooled. Continue reading
Ferroelectricity is a property which material of ferroelectrics has. The material has polarization that can be reversed by application of an external electric field. The polarization of the material in the state that an external electric field does not be applied to it is called spontaneous polarization or remanent/remnant polarization. Though pyroelectric material also has the spontaneous polarization, it has no ferroelectricity because polarity of the polarization cannot be reversed by an external electric field. The material with ferroelectricity combines pyroelectric and piezoelectric properties.