* * *

      property of certain nonconducting crystals, or dielectrics, that exhibit spontaneous electric polarization (separation of the centre of positive and negative electric charge, making one side of the crystal positive and the opposite side negative) that can be reversed in direction by the application of an appropriate electric field. Ferroelectricity is named by analogy with ferromagnetism, which occurs in such materials as iron. Iron atoms, being tiny magnets, spontaneously align themselves in clusters called ferromagnetic domains, which in turn can be oriented predominantly in a given direction by the application of an external magnetic field.

      Ferroelectric materials—for example, barium titanate (BaTiO3) and Rochelle salt—are composed of crystals in which the structural units are tiny electric dipoles; (electric dipole) that is, in each unit the centres of positive charge and of negative charge are slightly separated. In some crystals these electric dipoles spontaneously line up in clusters called domains, and in ferroelectric crystals the domains can be oriented predominantly in one direction by a strong external electric field. Reversing the external field reverses the predominant orientation of the ferroelectric domains, though the switching to a new direction lags somewhat behind the change in the external electric field. This lag of electric polarization behind the applied electric field is ferroelectric hysteresis, named by analogy with ferromagnetic hysteresis.

      Ferroelectricity ceases in a given material above a characteristic temperature, called its Curie temperature, because the heat agitates the dipoles sufficiently to overcome the forces that spontaneously align them.

* * *

Universalium. 2010.

Look at other dictionaries:

  • Ferroelectricity — is a property of certain materials which possess a spontaneous electric polarization that can be reversed by the application of an external electric field.[1][2] The term is used in analogy to ferromagnetism, in which a material exhibits a… …   Wikipedia

  • ferroelectricity — feroelektra statusas T sritis fizika atitikmenys: angl. ferroelectricity; Seignette electricity vok. Ferroelektrizität, f; Seignetteelektrizität, f rus. сегнетоэлектричество, n; ферроэлектричество, n pranc. ferro électricité, f …   Fizikos terminų žodynas

  • ferroelectricity — noun see ferroelectric …   New Collegiate Dictionary

  • ferroelectricity — noun The electric polarization of a substance (spontaneous presence of a dipole moment) that is analagous to ferromagnetism See Also: ferroelectric …   Wiktionary

  • ferroelectricity — spontaneous alignment of electric dipoles within a material under the influence of an electric field, resulting in a hysteresis loop when the direction of electric field is switched …   Mechanics glossary

  • ferroelectricity — fer·ro·electricity …   English syllables

  • ferroelectricity — noun see ferroelectric I …   Useful english dictionary

  • Multiferroics — have been formally defined as materials that exhibit more than one primary ferroic order parameter simultaneously (i.e. in a single phase).[1] The four basic primary ferroic order parameters are ferromagnetism, ferroelectricity, ferroelasticity… …   Wikipedia

  • Ceramic materials — Ceramic Si3N4 bearing parts Ceramic materials are inorganic, non metallic materials and things made from them. They may be crystalline or partly crystalline. They are formed by the action of heat and subsequent cooling.[1] Clay was one of the… …   Wikipedia

  • Paraelectricity — is the ability of many materials (specifically ceramic crystals) to become polarized under an applied electric field. Unlike Ferroelectricity; this can happen even if there is no permanent electric dipole that exists in the material, and removal… …   Wikipedia