Geometry.Net - Basic_S: Superconductors

Physics Central Physics In Action - Superconductivity
These elements require cooling by liquid helium to become superconductors.Such materials are called lowtemperature superconductors. .
http://www.physicscentral.com/action/action-01-3.html

Extractions: matters of state gravity waves far out planets whole grains ... physics in action archives About Superconductivity How would you like to board a Maglev train and then speed off to your destination at more than 300 miles per hour? The magnets that levitate these trains are an application of superconductivity Metals are good conductors of electric current. That is, they have very low electrical resistance, but this resistance is not zero. A voltage difference is still required to generate the current in the metal, and the metal heats up while the current is flowing. The electrical resistance of an object depends on its temperature and declines slowly as the temperature falls. Early in the last century, however, a Dutch physicist discovered that a sample of mercury, when cooled below a certain temperature close to absolute zero, loses all electrical resistance. When the mercury is in this state, an electric current flows indefinitely, even in the absence of any applied voltage. This effect is called "superconductivity." The table lists the everyday metals that exhibit superconductivity and the temperature below which electrical resistance disappears. These elements require cooling by liquid helium to become superconductors. Such materials are called "low-temperature superconductors." Much later, in the 1980s, physicists discovered ceramic compounds that exhibit superconductivity at temperatures as high as -145º Celsius. This temperature is high enough that the materials need be cooled only with liquid nitrogen, which is far less expensive to do than with liquid helium.
Intermagnetics General Corporation | Introduction
IGC is a developer and manufacturer of superconducting materials, radiofrequency coils, magnets, superconducting wire, cable and tape, and related refrigeration equipment. In Latham, New York, with manufacturing plants in several states. Several major divisions, including IGC-SuperPower, IGC-APD Cryogenics, and IGC-Advanced superconductors (IGC-AS).
http://www.igc.com
Organic Superconductors
Their history started in 1964 when Bill Little (Stanford U.) suggested that thecritical temperature of superconductors could be increased and he applied his
http://physics.clarku.edu/superconductor/superconductor.html

Extractions: Organic conductors are materials made of relatively large organic molecules, about 20 atoms each. Their history started in 1964 when Bill Little (Stanford U.) suggested that the critical temperature of superconductors could be increased and he applied his theory to a polymer chain. Most materials composed of organic molecules are normally not metals because of hybridization which leaves their conduction and valence bands filled. This property was first overcome by combining planar organic molecules with nonorganic anions (ClO , PF etc.) which serve as acceptors or donors thus resulting in the appearance of partially filled conduction and/or valence bands. Such materials are called charge transfer salts. In 1981 Bechgard synthesized (TMTSF) ClO (see diagram below), the first organic material that was superconducting at ambient pressure. Although, it has a relatively low superconducting transition temperature (1.2 K), the interest in superconductivity and other rather unusual properties in organic materials exploded after this discovery. Because organic conductors are complicated organic salts, they have many free parameters that can be adjusted to carefully fine tune their chemical structure. Consequently their electronic sucture can also be esily adjusted and fine tuned. In addition their electronic structure is unique because they have low Fermi energies and are electronically very clean, making it easy to study the intricacies of their Fermi surfaces through the observation of quantum oscillations. The low Fermi energy makes high magnetic field experiments more interesting due to the impact of the magnetic energy on the Fermi surface structure. As an example, Ef = 7.0 eV for Pb, whereas Ef for a typical organic is approximately 0.01 eV (50 T ~ 0.003 eV). These properties make them ideal for a number of solid state physics studies such as the ones descirbed below.
LHC - The Large Hadron Collider Home Page
A very interesting discussion of superconductors, cryogenics and magnets.
http://cern.web.cern.ch/CERN/LHC/YellowBook95/LHC95/LHC95.html

Extractions: General Information Organization Publications Seminars Illustrations CERN Click here to go to the LHC Progress Dashboard Beam Parameters Hardware Parameters Click here to go to the LHC General Co-ordination Schedule Design Performance Cryogenics Beam Dynamics ... Layout Integration Installation General Tunnel Who's Who ... Pits and Surface Buildings Access Permits List of Assemblies General Documentation Database Navigator Installation Drawings Database Utilities Equipment Catalog EDMS Doc. Version Management Baseline Documentation ...
Superconductors
next up previous contents index Next Questions Up Diamagnets and superconductorsPrevious Diamagnets and superconductors. superconductors.
http://theory.uwinnipeg.ca/mod_tech/node107.html

Extractions: Superconductors An extreme example of a diamagnet is a superconductor . These materials are known primarily through their electrical properties - at some relatively low temperature their electrical resistance is exactly zero. Thus, one can establish a current in a superconductor and it will never die away due to resistance, even when the source of potential difference that started the current is removed. Superconductors also have interesting magnetic properties; they are perfect diamagnets: when an applied magnetic field is applied, eddy currents in the superconductor induce a magnetic field which exactly cancels the applied magnetic field. This is the Meissner effect This effect is responsible for the magnetic levitation of a magnet when placed above a superconductor. Suppose, as in Fig. , we place a magnet above a superconductor. The induced magnetic field inside the superconductor is exactly equal and opposite in direction to the applied magnetic field, so that they cancel within the superconductor. What we then have are two magnets equal in strength with poles of the same type facing each other. These poles will repel each other, and the force of repulsion is enough to float the magnet. Such magnetic levitation devices are being tried on train tracks in Japan; if successful, this would make train travel much faster, smoother, and more efficient due to the lack of friction between the tracks and train (in some cases, rather than superconductors, strong electromagnets are used to provide the magnetic levitation).
Diamagnets And Superconductors
next up previous contents index Next superconductors Up Currents from magnetismPrevious Magnetic tape reader. Diamagnets and superconductors. superconductors.
http://theory.uwinnipeg.ca/mod_tech/node106.html

Extractions: Diamagnets and superconductors There exists a class of materials called diamagnets which exhibit some interesting properties when an external magnetic field is applied. In these materials, eddy currents consisting of circulating electrons are induced whose magnetic effects are such as to cancel part of the applied external field (typically about 0.1%). A metal detector is a device which relies on this property. In this device, a magnetic field is generated from an electromagnet, which causes eddy currents to be produced. The magnetic fields from the induced currents are in turn picked up by the detector in the form of small currents being produced. Most diamagnetic materials are metals, which have good electrical conductivity properties and so the eddy currents can be relatively easily established. This is the reason these detectors can readily sense metallic objects but not plastics or other poor conductors.
Superconductors - Georg Bednorz And Karl Alex Müller
breathing new life into a dying branch of physics and posing a daunting problem fortheorists explaining how high-temperature superconductors work.
http://inventors.about.com/library/inventors/blsuperconductors.htm

Extractions: Superconductors K. Alex Mueller IBM Press Release: K. Alex Mueller, along with his colleague, J. Georg Bednorz, was awarded the Nobel Prize in Physics in 1987 for his discovery of high-temperature superconductivity in a new class of materials. Drs. Mueller and Bednorz startled the world by reporting superconductivity in a layered, ceramic material at a then-record-high temperature 33 degrees above absolute zero, or Kelvin (roughly -460 degrees Fahrenheit). Their discovery set off an avalanche of research worldwide into related materials that yielded dozens of new superconductors, eventually reaching a transition temperature of 135 Kelvin. Born in Basle, Switzerland, on April 20, 1927, Dr. Mueller was educated at the Evangelical College in Schiers, Switzerland, and received his doctorate degree from the Swiss Federal Institute of Technology in Zurich in 1958. After spending five years at the Battelle Institute in Geneva as a project manager, he joined the IBM Zurich Research Laboratory in 1963. The University of Zurich appointed him a Lecturer in 1962, Titular Professor in 1970 and Professor in 1987. Dr. Mueller was manager of the physics department of the IBM Zurich Research Laboratory from 1973 to 1985. After that, he devoted his time fully to basic research. He was appointed an IBM Fellow in 1987. He retired from IBM in 1992.
The Maglev 2000 Of Florida Corporation
superconductors history. Certain materials, when cooled below their transitiontemperatures, become superconducting that is, electrical
http://www.maglev2000.com/works/how-07.html

Extractions: Superconductors history Certain materials, when cooled below their transition temperatures, become superconducting - that is, electrical currents travel in them with zero resistance. There is no resistive heating, and if the superconductor forms a closed circuit, the current will continue to flow forever, without any voltage drop or decrease in magnitude. In this mode, superconductor circuits can serve as powerful, lightweight permanent magnets. A detailed description of the physics of superconductivity is complex, and beyond the scope of this summary. Basically, at sufficiently low temperatures, the conducting electrons drop down to an energy level below their normal state. In this new state, the electrons can travel through the superconductor without colliding with, and losing energy to, its atomic matrix. Because they lose no energy, they can travel forever through the conductor, needing no voltage input. Superconductivity was discovered in 1911 by Kamerlingh Ohnes, the first person to liquefy helium. Since then, there has been a continued rise in superconductor transition temperatures. High transition temperatures are desirable, because the amount of electric power input to the refrigerator that keeps the superconductor at low temperature decreases as transition temperature increases. For example, at 4.2 degrees Kelvin, the normal boiling point of liquid helium, to keep the superconductor cold, approximately 500 watts of electrical power is consumed by the 4.2 K refrigerator to remove one watt of thermal heat that leaks in through the surrounding insulation. (4.2 degrees Kelvin is equivalent to minus 459 degrees Fahrenheit - a very cold place indeed.)
Living Up To The Hype: Superconductors
NASA Science News NASA has helped make a giant leap toward the realizationof superconductors. Living up to the Hype superconductors.
http://science.nasa.gov/headlines/y2003/05feb_superconductor.htm

Extractions: Headlines the world over trumpeted the discovery of "high temperature" superconductors (abbreviated HTS), and the media and scientists alike gushed over the marvels that we could soon expect from this promising young technology. Levitating 300-mph trains, ultra-fast computers, and cheaper, cleaner electricity were to be just the beginning of its long and illustrious career. Above : The experimental "maglev" train, currently being tested by Japan's Railway Technical Research Institute , uses "old fashioned" low-temperature superconductors that require liquid helium for a coolant. High-temperature superconductors can use liquid nitrogen instead, which is cheaper, more abundant, and easier to handle. Image courtesy RTRI Today we might ask, like a Hollywood gossip columnist: what ever happened to the "high-temp" hype?
WestTech MIS - What Are Superconductors?
A Brief History of superconductors The first discovery of a superconductive materialtook place in 1911 when a Dutch scientist named Heike Kammerlingh Onnes
http://www.superconductorweek.com/superconductors.htm

Extractions: Superconductors are materials that conduct electricity with no resistance. This means that, unlike the more familiar conductors such as copper or steel, a superconductor can carry a current indefinitely without losing any energy. They also have several other very important properties, such as the fact that no magnetic field can exist within a superconductor. Superconductors already have drastically changed the world of medicine with the advent of MRI machines, which have meant a reduction in exploratory surgery. Power utilities, electronics companies, the military, transportation and theoretical physics have all benefited strongly from the discovery of these materials. A Brief History of Superconductors The first discovery of a superconductive material took place in 1911 when a Dutch scientist named Heike Kammerlingh Onnes cooled mercury down to -269° C. Practical difficulties involved with refrigeration meant that this phenomenon was of mostly theoretical interest until 1986, when new materials were discovered that became superconductive at -173° C. While this may still seem incredibly cold, it is far easier to reach these temperatures in an industrial setting. The discovery of these "High Temperature Superconductors" has created vast interest and an entire industry dedicated to the research and commercial development of these materials and their applications.
Corrosion Of Glass, Ceramics And Ceramic Superconductors
Corrosion of Glass, Ceramics and Ceramic superconductors. And. Expand thisnode, Section 4. Corrosion of Ceramic superconductors, Index, Text.
http://www.knovel.com/knovel2/Toc.jsp?BookID=362
Wiley Superconductors
superconductors (8), Listings 18, Sort listing by
http://www.wiley.com/cda/sec/0,,2834,00.html
High Temperature Superconductors
High Temperature superconductors. Ceramic materials are Energy Gap insuperconductors as a Function of Temperature. The effective energy
http://hyperphysics.phy-astr.gsu.edu/hbase/solids/hitc.html

Extractions: High Temperature Superconductors Ceramic materials are expected to be insulators certainly not superconductors, but that is just what Georg Bednorz and Alex Muller found when they studied the conductivity of a lanthanum-barium-copper oxide ceramic in 1986. Its critical temperature of 30 K was the highest which had been measured to date, but their discovery started a surge of activity which discovered superconducting behavior as high as 125 K. Click on any of the compound formuli for further details. Show phase diagram Index See also June 91 issue of Physics Today ( 7 articles). HyperPhysics Condensed Matter R Nave Go Back Cuprate Superconductor Phases Illustrative of the complexity of the high-temperature superconductor materials is this phase diagram which applies to the cuprate materials. At very low doping, they show the long range order of an antiferromagnet. Doping breaks up the antiferromagnetic order and they become insulators. Only with doping fraction between about 0.1 and 0.2 do they become superconductors. Index
Superconductors Power Up
superconductors Power Up They find uses in medicine and in cellphonesystems; the next step is Detroit's electric power grid. By
http://www.memagazine.org/backissues/january99/features/superpower/superpower.ht

Extractions: M ore than a decade has passed since the 1986 superconductivity milestone event, which introduced a new set of ceramic compounds that could conduct electricity without energy losses, at much higher temperatures than previously thought possible. c , its critical temperature for superconductivity. Already, because of the sophisticated magnets superconductors can produce, superconducting quantum interference devices (dubbed "SQUIDs") are being designed into nuclear magnetic resonance imaging equipment that has provided awe-inspiring insight into biological tissue make-up. MRI equipment has used superconducting components, like current leads, for years. Because high temperature superconductor (HTS) materials are ultrareceptive to high-frequency signals and cheap enough to cool in a remote box, superconductive communications filters are deployed in the infrastructure that carries wireless phone calls. Now, superconductors are heading, in small steps, into the power grid. Decades of work remain to be accomplished, but the science is ready for engineering development into our daily lives. One high-profile demonstration project has just begun in the United States. Energy Secretary Bill Richardson announced that the Department of Energy has contracted to install the world's first HTS power cable system in an electric utility network.
Nexans
superconductors. Nexans superconductors emerged from the HTS activitiesof the former Hoechst AG (Aventis Research and Technologies).
http://www.nexans.com/dyn/site.php3?page_id=313
Organic SuperConductors
Organic superconductors. Organic The smaller dark and light blue spheresrepresent an alkali metal. Making Organic superconductors. Organic
http://www.physics.uq.edu.au/people/brake/osc.html

Extractions: Organic superconductors are a recent addition to the group of known superconductors, and have been the subject of large amounts of research effort. They have properties that are different to most other superconductors, and a full understanding of their behavior has yet to develop. The following is a brief overview of the topic, and is intended to inspire an interest in the subject. The first interest in organic superconductors was aroused in 1964 when W A Little proposed a model of a superconductor that could possibly superconduct at very high temperatures. Little's model comprised of a conducting chain with polarisable molecules attached to it. These polarisable molecules would have a similar effect on electron movement as atoms in a normal superconductor do, but because the effects are caused by the movement of electrons, not whole atoms, the effects would be noticed at much higher temperatures. Unfortunately, Little's model is a one dimensional system, and so any superconducting properties would be destroyed due to a Peierls transition, which would destroy the homogenousity of the material, and so cause the material to enter an insulating phase.
High Tc Cuprate Superconductors
High Tc Cuprate superconductors. Introduction. They are type II superconductors,and have a number of unusual physical properties.
http://www.physics.uq.edu.au/people/brake/hsc.html

Extractions: The first High T c Cuprate Superconductors was found in 1986 by J. Georg Bednorz and K. Alexander Müller working at an IBM lab in Zurich. they found that lanthanum copper oxide doped with barium or strontium would superconduct up to 38K. This added around 10 degrees kelvin to the highest known critical temperature (T c , which had remained constant for twenty years, and broke the theoretical limit for T c , whih was 30K. Their discovery caused a great amount of research into these new superconductors, and the current record for T c now stands at 160K for a mercury based cuprate, as well as earning Bednorz and Müller the Nobel Prize in 1987, the shortest amount of time between a discovery and the awarding of a Nobel Prize for physics. General Properties High T c Cuprate Superconductors are made of crystals containg copper oxide (CuO ) and other atoms, usually rare earth elements, but other atoms such mercury have been used. They have a planar crystal stucture, with set of planes of copper oxide being seperated by planes of other atoms. The number of planes within a set of copper oxide planes is between one and three, and there are also layers of other atoms between the copper oxide planes within a set. However, the distances between copper oxide planes within a set of planes is much less than the distance between sets of planes, normally less than half.
Superconductors - III. Superconductors
III. superconductors. 3.1. Què és la superconductivitat? 3.2. Classes de superconductors.Els superconductors es poden classificar en dos grans grups.
http://www.geocities.com/treball_sc/supercon.html

Extractions: III. S UPERCONDUCTORS 3.1. Què és la superconductivitat? 3.1.1. Definició de superconductor Un superconductor és un element, una aleació inter-metàl·lica o un compost la propietat més important del qual és conduir el corrent elèctric sense resistència per sota d'una certa temperatura, anomenada temperatura crítica. Tots els superconductors coneguts són sòlids, cap és gas o líquid, i tots requereixen un fred extrem per passar a l'estat superconductor. Una vegada en moviment, el corrent elèctric circularà per sempre en un anell tancat de material superconductor. Els científics es refereixen a la superconductivitat com a un "fenomen quàntic macroscòpic" Tot i que es necessiten condicions força especials per poder observar la superconductivitat en un material, no és del tot estrany en els materials: gairebé una quarta part dels elements naturals són superconductors, i hi ha literalment milers de compostos i aleacions amb aquesta propietat. Malgrat tot, la superconductivitat només s'esdevé a temperatures molt per sota de les que estem acostumats L'estat superconductor és un estat més ordenat que l'estat normal del material, és a dir, té menys entropia. Tot i això, aquest major ordenament no és degut a l'estructura cristal·lina del àtoms, que no varia en passar de l'estat normal al superconductor, sinó als electrons, que si que estan més ordenats
Superconductors - Annex A: Materials Superconductors
Translate this page ANNEX A MATERIALS superconductors. superconductors Tipus I. En verd,superconductors sota pressions extremes. superconductors Tipus II.
http://www.geocities.com/treball_sc/annex_a.html

Extractions: A NNEX A: M ATERIALS SUPERCONDUCTORS Superconductors Tipus I Els elements de la següent llista són superconductors Tipus I coneguts, amb les seves Tc sota una pressió atmosfèrica normal. Sota altes pressions, alguns d'aquests elements poden augmentar la seva Tc, i altres elements poden esdevenir superconductors. La taula periòdica de sota mostra tots els elements superconductors coneguts, incluïts aquells que només ho són sota altes pressions i també el Niobi, el Tecneci i el Vanadi, que són superconductors Tipus II. Substància T c (K) H c (G), quan T Al (alumini) Am (americi) Be (beril·li) Cd (cadmi) Ga (gal·li) Gd (gadolini) Hf (hafni) Hg (mercuri) In (indi) Ir (iridi) La (lantani) Lu (luteci) Mo (molibdè) Nb (niobi) Os (osmi) Pa (protoactini) Pb (plom) Pt (platí) Re (reni) Rh (rodi) Ru (ruteni) Sn (estany) Ta (tàntal) Tc (tecneci) Te (tel·luri) Th (tori) Ti (titani) Tl (tal·li) U (urani) V (vanadi) W (tungstè) Zn (zinc) Zr (zirconi) Ferromagnètic per sobre T c diamagnètic per sota T c
Welcome To Gravity Control Technologies
Galactic Explorers Society Spin Off Technologies Technology ConsultingPower of the Dream Ventures. Types copper - gold - rhodium
http://www.gctspace.com/products/superconductors/

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