Ferroelectric effect

In physics, the ferroelectric effect is an electrical phenomenon whereby certain crystals may exhibit a spontaneous dipole moment (which is called ferroelectric by analogy with ferromagnetic - exhibiting a permanent magnetic moment[?]). The effect in the most typical case, barium titanate, is due to a polarization catastrophe[?], in which the local electric fields due to the polarization itself increase faster than the elastic restoring forces on the ions in the crystal, thereby leading to an asymmetrical shift in ionic positions and hence to a permanent dipole moment. Ferroelectric crystals often show several Curie points, domain structure hysteresis[?], much as do ferromagnetic crystals.