In physics, the ferroelectric effect is an electrical phenomenon whereby certain ionic crystals may exhibit a spontaneous dipole moment. The term ferroelectricity refers to the similarity with ferromagnetism, in which a material exhibits a permanent magnetic moment. Since antiquity, people have tried to understand the behavior of matter: why unsupported objects drop to the ground, why different materials have different properties, and so forth. ... Electrical phenomena are commonplace and unusual events that can be observed which illuminate the principles of the physics of electricity and are explained by them. ... Quartz crystal A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ... This article is about the electromagnetic phenomenon. ... Ferromagnetism is a phenomenon by which a material can exhibit a spontaneous magnetization, and is one of the strongest forms of magnetism. ... In physics, the magnetic moment of an object is a vector relating the aligning torque in a magnetic field experienced by the object to the field vector itself. ...

There are two main types of ferroelectrics: displacive and order-disorder. The effect in barium titanate, a typical ferroelectric of the displacive type, is due to a polarization catastrophe, in which, if an ion is displaced from equilibrium slightly, the force from the local electric fields due to the ions in the crystal increase faster than the elastic restoring forces. This leads to an asymmetrical shift in the equilibrium ion positions and hence to a permanent dipole moment. In an order-disorder ferroelectric, there is a dipole moment in each unit cell, but at high temperatures they are pointing in random directions. Upon lowering the temperature and going through the phase transition, the dipoles order, all pointing in the same direction within a domain. General Name, Symbol, Number barium, Ba, 56 Chemical series alkaline earth metals Group, Period, Block 2, 6, s Appearance silvery white Atomic mass 137. ... General Name, Symbol, Number titanium, Ti, 22 Chemical series transition metals Group, Period, Block 4, 4, d Appearance silvery metallic Atomic mass 47. ... Jump to: navigation, search In physics, an electric field or E-field is an effect produced by an electric charge that exerts a force on charged objects in its vicinity. ... There are separate articles about elasticity in economics, and about British rubber bands. ... In physics, a net force acting on a body causes that body to accelerate; that is, to change its velocity. ...

Another important ferroelectric material is lead zirconate titanate. Lead zirconium titanate (PZT, also Lead zirconate titanate) is a ceramic perovskite material that shows a marked piezoelectric effect - that is, it develops a voltage difference across two of its faces when compressed, and ferroelectric effect. ...

Ferroelectric crystals often show several Curie points and domain structure hysteresis, much as do ferromagnetic crystals. By analogy to magnetic core memory, this hysteresis can be used to store information in ferroelectric RAM, which has ferroelectric capacitors as memory cells. The nature of the phase transition in some ferroelectric crystals is still not well understood. Crystal (disambiguation) Insulin crystals A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ... In physics, the Curie point, or Curie temperature, is the temperature above which a ferromagnet loses its ferromagnetic ability to possess a net (spontaneous) magnetization in the absence of an external magnetic field. ... Jump to: navigation, search Hysteresis is a property of systems (usually physical systems) that do not instantly follow the forces applied to them, but react slowly, or do not return completely to their original state: that is, systems whose states depend on their immediate history. ... Ferromagnetism is a phenomenon by which a material can exhibit a spontaneous magnetization, and is one of the strongest forms of magnetism. ... A 16×16 cm area core memory plane of 128×128 bits, i. ... Ferroelectric RAM (FRAM) is a type of non-volatile memory similar to EEPROM but based on electric field orientation and with near-unlimited number (exceeding 1010 for 5V devices and even more for 3. ... Ferroelectric capacitor is a capacitor used in digital electronics as a component of computer memory. ... In physics, a phase transition is the transformation of a thermodynamic system from one phase to another. ...

Ferroelectrics often have very large dielectric constants, and thus are often found in capacitors. They also often have unusually large nonlinear optical coefficients. The dielectric constant εr (represented as or K in some cases) is defined as the ratio: where εs is the static permittivity of the material in question, and ε0 is the vacuum permittivity. ... Jump to: navigation, search Various types of capacitors A capacitor is a device that stores energy in the electric field created between a pair of conductors on which equal but opposite electric charges have been placed. ... Nonlinear optics is the branch of optics that describes the behaviour of light in nonlinear media, that is, media in which the polarization P responds nonlinearly to the electric field E of the light. ...

Older publications used the term electret for ferroelectric materials. Electret (formed of elektr- from electricity and -et from magnet) is material that has been permanently electrically charged (polarised). ...

See also

Physics

• Pyroelectricity
• Condensed matter physics
• Spintronics
• Ceramics

Jump to: navigation, search Pyroelectricity is the electrical potential created in certain materials when they are heated. ... Condensed matter physics is the field of physics that deals with the macroscopic physical properties of matter. ... Unsolved problems in physics: Is it possible to construct a practical electronic device that operates on the spin of the electron, rather than its charge? Spintronics (a neologism for spin-based electronics), also known as magnetoelectronics, is an emergent technology which exploits the quantum propensity of electrons to spin as... Jump to: navigation, search The word ceramic is derived from the Greek word Κεραμεικος (-keramos- the name of a suburb of Athens), and in its strictest sense refers to clay in all its forms. ...

People

• Oliver Heaviside

Oliver Heaviside (May 18, 1850 – February 3, 1925) was a self-taught English engineer, mathematician and physicist who adapted complex numbers to the study of electrical circuits, developed techniques for applying Laplace transforms to the solution of differential equations, reformulated Maxwells field equations in terms of electric and magnetic...

Lists

• Examples of electrical phenomena
• List of physics topics
• List of electronics topics