Ferro electric crystals are classified into two main groups 1.Displacive Type 2.Order-Disorder Type Displacive: If in the Paraelectric state the atomic displacements or oscillations about a non polar site then after a displacive transition the oscillations are about a polar site. If the soft optical phonon mode can propagate in a crystal at the transition is displacive. it induces ionic crystal structures closely related to Perovskite and Ilmenite. Order-Disorder: If in the paraelectric phase the displacements are about some Double well or multi well configuration of sites then in an order- disorder transition the dispacements are about an ordered subset of these wells.
Yes, there are naturally occurring crystals present in the human body, such as calcium oxalate crystals in the kidneys and uric acid crystals in joints.
Double refraction in calcite crystals occurs due to the unique arrangement of atoms within the crystal structure, which causes light to split into two separate rays when passing through the crystal. This phenomenon is significant in mineralogy because it allows for the identification of calcite crystals and helps in determining their orientation and properties. Additionally, double refraction can provide valuable information about the internal structure and composition of minerals, aiding in their classification and study.
Snowflakes and snow crystals are both formed from frozen water vapor, but they have different structures. Snowflakes are clusters of snow crystals that stick together as they fall from the sky. Snow crystals are individual ice crystals that form in the atmosphere. Snowflakes can have a variety of shapes and sizes, while snow crystals typically have a hexagonal shape.
Sandstone typically does not have crystals. It is primarily composed of sand-sized mineral particles that are cemented together, giving it a granular appearance. If sandstone does contain crystals, they are usually very small and not easily visible to the naked eye.
Becquerel left his crystals in the sunlight to study the phenomenon of fluorescence. He discovered that the uranium crystals emitted radiation that fogged photographic plates, leading to the discovery of radioactivity.
V. L. Aksenov has written: 'Neutron scattering by ferroelectrics' -- subject(s): Diffraction, Ferroelectric crystals, Neutrons
Ferroelectric domains are regions within a ferroelectric material where the electric dipoles are aligned in a specific direction. These domains can switch orientation when an external electric field is applied, allowing the material to exhibit ferroelectric properties. The presence of domains allows ferroelectric materials to have unique properties such as piezoelectricity and non-volatile memory storage.
Iron is not ferroelectric. Ferroelectric materials possess a permanent electric dipole moment that can be reversed by an external electric field. Copper does not have this property because it lacks a crystal structure that allows for the alignment of dipoles.
A ferroelectric substance is a material that exhibits a spontaneous electric polarization that can be reversed by the application of an external electric field. This property allows ferroelectric materials to be used in various applications such as memory storage devices, sensors, and actuators. Examples of ferroelectric substances include lead zirconate titanate (PZT) and barium titanate.
Not ferrous, but ferroelectric !
In physics the ferroelectric effect is an electrical phenomenon whereby certain materials may exhibit a spontaneous dipole moment, the direction of which can be switched between equivalent states by the application of an external electric field. Placing a ferroelectric material between two conductive plates creates a ferroelectric capacitor. Ferroelectric capacitors exhibit nonlinear properties and usually have very high dielectric constants. The fact that the internal electric dipoles can be forced to change their direction by the application of an external voltage gives rise to hysteresis in the "polarization vs voltage" property of the capacitor. In this case, polarization is defined as the total charge stored on the plates of the capacitor divided by the area of the plates. Hysteresis means memory and ferroelectric capacitors are used to make ferroelectric RAM for computers and RFID cards. Above retrieved from Answers.com Viper1
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The hysteresis loop of ferroelectric materials can be measured using a ferroelectric tester or a precision impedance analyzer. These instruments apply a voltage sweep to the material and measure the resulting polarization response, capturing the hysteresis loop which shows the relationship between polarization and applied electric field.
Rosemary M Dyer has written: 'The classification of ambiguous ice particle shadowgraphs by consensus' -- subject(s): Ice crystals, Classification, Particle size determination
Its not true that electrocaloric effect (ECE) is observed only in ferroelectric polymers. ECE can be found in any typical dielectric material. If polarization switches from one direction to the other upon application or withdrawl of electric filed, the temperature of the material changes. It happens both in organic as well as inorganic materials. It is found that the EC coefficent is high near ferroelectric phase transition temperature.
Todd C. MacLeod has written: 'Modeling of metal-ferroelectric-semiconductor field effect transistors' -- subject(s): Field effect transistors, Current density, Electric potential, Ferroelectric materials, Mathematical models, Hysteresis
Steven W. Wood has written: 'Ferroelectric memory design'