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Topic: Ferroelectric effect

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	U.S. Patent: 5198994 - Ferroelectric memory device - March 30, 1993
		The nonvolatile semiconductor memory according to claim 1, wherein said ferroelectric insulation film is a ferroelectric gate insulation film, and said first field-effect transistor comprises a semiconductor substrate and a non-ferroelectric insulation film between the semiconductor substrate and said ferroelectric gate insulation film.
		The nonvolatile semiconductor memory according to claim 10, wherein said ferroelectric insulation film is a ferroelectric gate insulation film, and said first field-effect transistor comprises a semiconductor substrate and a non-ferroelectric insulation film formed between the semiconductor substrate and said ferroelectric gate insulation film.
		Since the ferroelectric insulation film fails to function normally after it has undergone inversion of polarization a predetermined number of times, the capacitor cannot be used long as a memory cell.
	www.everypatent.com /comp/pat5198994.html (4784 words)

	Ferroelectric transistors, semiconductor storage devices, method of operating ferroelectric transistors and method of ...
		The above-mentioned ferroelectric transistor may prevent the constituting elements of the ferroelectric from being diffused in the course of a heated process, simplify the wiring process, facilitate the control of the elements and thus is suitable for obtaining a fine structure of the device.
		In this structure, the diffusion of the constituting elements of the ferroelectric in a thermal process may be avoided, the wiring or the interconnection may be simpler, the device may be controlled in an easier manner, and an integration to a further microscopic level may be possible.
		Further, in accordance with a method of manufacturing the ferroelectric transistor of the present invention, between the formation of the ferroelectric layer 70 and the formation of the first insulation layer 72, a third conductive layer is formed on the ferroelectric layer is inserted.
	www.freepatentsonline.com /6107656.html (16467 words)

	Applications of Ferroelectric Ceramic Materials
		The biggest use of ferroelectric ceramics have been in the areas such as dielectric ceramics for capacitor applications, ferroelectric thin films for non volatile memories, piezoelectric materials for medical ultrasound imaging and actuators, and electro-optic materials for data storage and displays.
		C, the ferroelectric orthorhombic phase is stable with the polarization along one of the [110] directions in the original cubic structure.
		Hence the piezoelectric and pyroelectric properties depend on the degree of crystallinity of the polymer and the ferroelectric polarization of the crystalline phase [63, 64].
	www.rci.rutgers.edu /~ecerg/projects/ferroelectric.html (10045 words)

	Colossal Storage Corp. -The Atomic / Photonic / Quantum Switch-
		Ferroelectric densities of.2 to.5 Petabits = 200 to 500 Terabits sq.
		A ferroelectric storage drive device the size of an iPod nano or 3.5 inch drive could hold enough MP3 music to play for 300,000 years without repeating a song or enough DVD quality video to play movies for 10,000 years without repetition.
		Certain crystals also exhibit a linear electro-optic effect such that the birefringence occurs when it is placed in an electric field and a beam of light is passed through the sample in the direction of the field.
	www.colossalstorage.net /colossal5j.htm (1937 words)

	Crystal Growing K-12 Experiments for Lesson Plans & Science Fair Projects
		Some crystalline materials may exhibit special electrical properties such as the ferroelectric effect or the piezoelectric effect.
		This is analogous to ferromagnetism, in that, in the absence of an electric field during production, the ferroelectric crystal does not exhibit a polarisation.
		However, it is important to note that, although they are called ferroelectrics, the effect is due to the crystal structure, not the presence of a ferrous metal.
	www.juliantrubin.com /encyclopedia/chemistry/crystal.html (2408 words)

	Ferroelectricity - Wikipedia, the free encyclopedia
		In physics, the ferroelectric effect is an electrical phenomenon whereby certain ionic crystals and piezoelectric polymers may exhibit a spontaneous dipole moment, which can be reversed by the application of an electric field.
		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.
		Ferroelectrics often have very large dielectric constants, and thus are often used as the dielectric material in capacitors.
	en.wikipedia.org /wiki/Ferroelectric_effect (446 words)

	[No title]
		Time-dependent change of ferroelectric, dielectric and piezoelectric properties (so-called aging phenomena) is well observed in ferroelectrics and is an important issue both in physics and in applications.
		The result of this important experiment excludes the long-believed mysterious "domain-wall-pinning effect" as the primary origin of aging, and strongly suggests that volume effect is the governing mechanism for ferroelectric aging.
		With this clear microscopic mechanism, she is able to explain all known ferroelectric aging effect, including not only the aging in large signal properties (hysteresis loop), but also the small signal aging of dielectric and piezoelectric constant.
	unit.xjtu.edu.cn /mmrc/news_en/LXZhang06_03_01.htm (210 words)

	Semiconductor nonvolatile storage element and method of fabricating the same - Patent 6784473
		Other thereof is a ferroelectric transistor having a structure of MFMIS (Metal-Ferroelectric-Metal-Insulator-Semiconductor) (or conductor layer-ferroelectric layer-conductor layer-insulating layer-semiconductor) as a gate structure, in which a conductor layer (M) (or referred to as floating gate) is sandwiched between a ferroelectric layer (F) and an insulating layer (I) of an MFIS structure.
		Voltage distributed to the ferroelectric capacitor is dependent on a coupling ratio (C.sub.I /(C.sub.I +C.sub.F)) between the capacitance (C.sub.F) of the ferromagnetic capacitor and the capacitance (C.sub.I) of the gate insulator capacitor.
		According to the constitution of the invention, in the ferroelectric nonvolatile storage element including the field effect transistor, the second insulator thin films are interposed between the third and the fourth conductors of the source portion and the drain portion of the semiconductor substrate and the first conductor layer of the gate portion.
	www.freepatentsonline.com /6784473.html (6723 words)

	NEPP - Parts Experts (Site not responding. Last check: 2007-10-11)
		Ferroelectric memory (FRAM) is a RAM-based device that uses the ferroelectric effect as the charge storage mechanism, and is very different from the floating-gate based nonvolatile memories.
		The ferroelectric effect is the ability of material to store an electric polarization in the absence of an applied electric field.
		A FRAM memory cell is fabricated by depositing a film of ferroelectric material in crystal form between two electrode plates to form a capacitor, which is very similar to a DRAM capacitor.
	nepp.nasa.gov /index_nasa.cfm/469/2D8DF528-6D10-4DEA-92CB51F8B362F8A4 (312 words)

	Ferroelectric dynamic random access memory - Patent 6067244
		The memory of claim 4 wherein in each memory cell in the array of memory cells, the select transistor is connected to a gate of the ferroelectric FET in that memory cell.
		The memory of claim 4 wherein in each memory cell in the array of memory cells, the select transistor is connected to one of a source and drain of the ferroelectric FET in that memory cell.
		Without a buffer layer between the ferroelectric film and the underlying semiconductor, it is also difficult to avoid inter-diffusion between elements in the ferroelectric film and the semiconductor, which can either degrade the ferroelectric properties or the transistor characteristics (or both) of the FEDRAM.
	www.freepatentsonline.com /6067244.html (4900 words)

	"Bionic" Eye (Site not responding. Last check: 2007-10-11)
		Ceramic optical detectors based on the photo-ferroelectric effect are being developed for direct implantation into the eyes of patients with retinal dystrophies.
		The detector currently being developed for this application jointly with the University of Texas Health Science Center is a thin film ferroelectric detector, which under optical illumination can generate a local photocurrent and photovoltage.
		The local electric current generated by this miniature detector excites the retinal neural circuit resulting in a signal at the optic nerve that may be translated by the cortex of the brain as "seeing light".
	www.svec.uh.edu /BIONIC.html (188 words)

	Small defects have large impact
		This so-called size effect, the sources of which may be quite diverse, can be a road block for the miniaturization of electronic, electromechanic, and electrooptic components.
		Ferroelectric oxides can be used to construct "non-volatile" memory cells in silicon-based microelectronics - cells that do not lose their information when the supply voltage is switched off.
		If the ferroelectric island is so small that most of its volume consists of such tubes of deformed material, the island has no longer any storing properties.
	www.eurekalert.org /pub_releases/2004-01/m-sdh011904.php (731 words)

	Water, nanoelectronics will mix to create ultra-dense memory storage
		Ferroelectrics are technologically important "smart" materials for many applications because they have local dipoles, which can switch up and down to encode and store information.
		In this investigation, led by Hongkun Park of Harvard and Andrew Rappe of Penn, the researchers probed oxide nanowires individually to characterize the size-dependence of ferroelectricity and performed calculations and experiments to validate the presence of molecules on oxide surfaces and detail their important role in nanoscale ferroelectricity.
		The dipoles electrical polarity of the ferroelectric molecule physically changes the transmiscivity, spintronics, interference, excitons, diffraction, surface morphology / topography, opacity, fluorescence, iridescence, positive and negative index of refraction, and opalescence.
	www.physorg.com /news65283661.html (771 words)

	Ceramic - find information about Ceramic at BigServing.com (Site not responding. Last check: 2007-10-11)
		Barium titanate (often mixed with strontium titanate) displays ferroelectricity, meaning that its mechanical, electrical, and thermal responses are coupled to one another and also history-dependent.
		The piezoelectric effect is generally stronger in materials that also exhibit pyroelectricity, and all pyroelectric materials are also piezoelectric.
		In turn, pyroelectricity is seen most strongly in materials which also display the ferroelectric effect, in which a stable electric dipole can be oriented or reversed by applying an electrostatic field.
	www.bigserving.com /bigserving/ceramic.htm (4867 words)

	Ferroelectric/Semiconductor Tunable Microstrip Patch Antenna Developed (Site not responding. Last check: 2007-10-11)
		The structure consists of a rectangular metallic "patch" radiator patterned on a thin ferroelectric film that was grown on high-resistivity silicon.
		Operating the antenna in a higher order odd mode produced a second useful frequency of operation, and the ferroelectric effect was used for vernier tuning.
		This phenomenon is believed to be due to a tunneling process that may be enhanced by the polarization of the ferroelectric layer.
	www.grc.nasa.gov /WWW/RT2000/5000/5640romanofsky.html (526 words)

	Local switching of two-dimensional superconductivity using the ferroelectric field effect: Nature
		Atomic force microscopy is used to locally reverse the ferroelectric polarization, thus inducing large resistivity and carrier modulations, resulting in a clear shift in the superconducting critical temperature.
		Field-induced switching from the normal state to the (zero resistance) superconducting state was achieved at a well-defined temperature.
		Impact of misfit dislocations on the polarization instability of epitaxial nanostructured ferroelectric perovskites
	www.nature.com /nature/journal/v441/n7090/abs/nature04731.html (351 words)

	MMRC
		Ferroic materials play an indispensable role in our modern society as major functional materials, and are expected to gain their importance in our electronic and information age in which conversion of different forms of energy (mechanical, electrical, magnetic, etc) is crucial.
		However, in recent years it has been gradually realized that fundamental physics in these apparently different groups of material bears striking similarity or analogy, and knowledge obtained in one group of materials can be applied to understanding parallel physical phenomena in other groups.
		Possible exotic multiscale phenomena in ferroelectric materials, effect of point defect, aging effect, possible colossal piezoelectric effect and unusual memory effect.
	unit.xjtu.edu.cn /mmrc/research/research_en.htm (520 words)

	Session AT2 - Plasma Propulsion.
		Ferroelectric emission (FEE) cathodes are currently being studied at the NASA Glenn Research Center as zero expellant flow rate cathodes sources.
		The cathodes rely on the strong ferroelectric effect, induced by rapidly pulsing several kV across a ferroelectric ceramic, to emit electrons.
		The effects of ferroelectric dielectric constant, grid geometry, and pulse geometry are being examined.
	flux.aps.org /meetings/YR01/GEC01/abs/S20.html (839 words)

	Search results : ferroelectric : Nature (Site not responding. Last check: 2007-10-11)
		SUMMARY: A ferroelectric crystal exhibits a stable and switchable electrical polarization that is manifested in the form of cooperative atomic displacements.
		CONTEXT: One main difference between ferroelectric (FE) nanostructures and (infinite) bulk materials is the existence in the former of depolarizing field, because of the uncompensated...
		In the ferroelectric crystal or crystallite, there is a substructure of electrically polar domains that can...
	search.nature.com /search/?sp-q=ferroelectric&sp-x-9=cat&sp-s=date&sp-q-9=Nature&sp-a=sp1001702d&sp-sfvl-field=subject\|ujournal&sp-t=results&sp-x-1=ujournal&sp-p-1=phrase&sp-p=all (459 words)

	Session K38 - General Poster Session II.
		The effect of quenching on the dielectric behavior of PLZT 7/70/30 and 11/65/35 ceramics is studied.
		A decrease in the lattice constants was observed with an increase in Sr concentration.
		Effects of tip/sample bias polarity present in these images are attributed to the semiconductor nature of the surface layers.
	flux.aps.org /meetings/YR98/BAPSMAR98/abs/S2225.html (15660 words)

	[No title] (Site not responding. Last check: 2007-10-11)
		] The dependence of the polarization of ferroelectric materials not only on the applied electric field but also on their previous history; analogous to magnetic hysteresis in ferromagnetic materials.
		] An electronic display that employs a liquid crystal that is ferroelectric, such as smectic C*, which has two different stable molecular configurations; polarizers are positioned such that one state is optically transmissive while the other is dark.
		] A shutter consisting of a slab of ferroelectric crystal located between polarizers whose planes are at right angles; opens to pass light when activated by a pulse of up to 100 volts.
	www.accessscience.com /Dictionary/F/F6/DictF6.html (1365 words)

	Ferroelectric capacitor - Wikipedia, the free encyclopedia
		Ferroelectric capacitor is a capacitor used in digital electronics as a component of ferroelectric RAM, a type of non-volatile computer memory.
		In a ferroelectric capacitor, the dielectric layer is replaced with a thin ferroelectric film, typically made of lead zirconate titanate (PZT).
		The stored value is read by applying an electric field on the memory capacitor.
	en.wikipedia.org /wiki/Ferroelectric_capacitor (184 words)

	Title page for ETD etd-092099-110827 (Site not responding. Last check: 2007-10-11)
		Three types of major process-induced damage which hampers the realization of FRAM (ferroelectric random access memory) device are investigated; dry etching induced damage, hydrogen-induced degradation, and stress effect.
		Since ferroelectric capacitors utilize the movement of body-centered atoms in perovskite structure, Ti or Zr in the case of Pb(Zr/x Ti/1-x)O3 (PZT), the movement can be suppressed or inhibited by many factors such as space charges, defects, chemical reactions, and stress of stacked layers.
		Unlike conventional silicon processes, the integration of ferroelectric capacitor module requires high density plasma to pattern their shapes because of a low volatility of etched byproducts, therefore the degradation of ferroelectric capacitor performance could occur by the collision of high energetic particles.
	scholar.lib.vt.edu /theses/available/etd-092099-110827 (609 words)

	Size Effect in Ferroelectric Materials (Site not responding. Last check: 2007-10-11)
		Ferroelectric ceramic have been used in a diverse field of applications including multilayer capacitors, resonators, sensors, actuators, electro-optics, nanocomposites and thin films.
		Miniaturization of electronic components and the design of smart integrated structure has been the major trend in electronic applications for the last decade imposing very high requirements on material properties in terms of performance and microstructure.
		The purpose of this project is to contribute to the elucidation of the underlying physico-chemical phenomena associated with the finite crystal size effects in ferroelectric polycrystals and to compare the behavior of of an psuedo-cubic ferroelectric (BaTiO
	www.rci.rutgers.edu /~ecerg/projects/p11.html (154 words)

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