What is Ferro Electricity?
Ferro-electricity is defined as the spontaneous alignment
of electric dipoles in the absence of an external field. The spontaneous polarization results from the relative
displacement of cations and anions from their symmetrical
positions. Therefore, ferroelectric materials must possess
permanent dipoles. Examples of ferroelectric materials: BaTiO₃, Rochelle salt
(NaKC₄H₄O₆ .4H₂O), potassium dihydrogen phosphate
(KH₂PO₄), potassium niobate (KNbO₃ ), lead zirconate
titanate [Pb (ZrO₃, TiO₃)]. These materials have extremely high dielectric constants
at relatively low applied field frequencies. Hence,
capacitors made from ferroelectric materials are smaller
than those made from other dielectric materials.
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| Ferro Electricity |
What is Piezoelectricity?
Piezo-electricity is defined as the conversion of electrical
energy into mechanical strain and vice versa. It arises due to polarization induced by an external force.
Thus by reversing the direction of external force, the direction of
the established field can be reversed i.e. the application of an
external electric field alters the net dipole length causing a
dimensional change. Application for these materials includes microphones,
ultrasonic generators, sonar detectors, and mechanical strain
gauges. Examples: Barium titanate (BaTiO₃), lead titanate (PbTiO₃), lead zirconate
(PbZrO₃), ammonium dihydrogen phosphate (NH₄H₂PO₄ ),
and quartz.
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| Piezoelectricity |