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
forcess 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.