PhysicsWeb - Explaining High-Tc Superconductors Explaining highTc superconductors Physics in Action December 1999. Thisis what gives superconductors their unusual properties. http://physicsweb.org/article/world/12/12/3
Extractions: Even a decade and a half after the discovery of high-temperature superconductivity in ceramic compounds containing copper-oxide planes, these materials continue to puzzle condensed-matter theorists. The challenge is not simply to find a reasonable formula that predicts the uniquely high values for the superconducting transition temperature in the cuprates. Rather, superconductivity is but one aspect of the unique and complex phase diagram exhibited by this class of materials. Depending on the temperature and the level of doping, the cuprates can be insulators, metals or superconductors. The non-superconducting or "normal" phase also exhibits unusual properties (see figure). c , of 36 K. Similar materials with higher transition temperatures soon followed, including yttrium barium copper oxide (YBCO), which has a T
PLUTONIUM SUPERCONDUCTOR Describes the way that scientists found a way to use plutonium as a supercondutor. http://superconductors.org/PlutonSC.htm
Extractions: GAINESVILLE, Fla. - Scientists have discovered superconductivity in a most unlikely place: the highly radioactive element used to make nuclear weapons. In an article in the journal Nature , a group of researchers, including a University of Florida physicist, report discovering a plutonium-based electrical superconductor. The finding is significant because plutonium, the active ingredient in atomic bombs, has physical properties that should prevent it from behaving as a superconductor - suggesting current theories about this phenomenon may not apply to this element. This is anomalous superconductivity, which is fascinating, said Gregory Stewart, a UF professor of physics and contributing author to the paper. Stewart said John Sarrao, the lead author on the Nature paper, and his colleagues at the Los Alamos National Laboratory in New Mexico discovered the plutonium compound PuCoGa superconducted while they were measuring its magnetic behavior. To their surprise, a probe of the materials magnetic properties revealed diamagnetic, or anti-magnetic behavior, a telltale indicator of superconductivity, he said. That was unexpected because plutonium, a heavy element in the actinide group, very often forms compounds that are highly magnetic; never before had a compound containing plutonium been found to be superconducting.
Making High-Temperature Superconductors Making HighTemperature superconductors. Copyright 1988, Colorado Futurescience,Inc. What follows the air. TESTING THE superconductors. http://www.futurescience.com/scpart1.html
Extractions: What follows are the instructions for making ceramic superconductors in a high school science laboratory. These were originally the instructions that were included in a Colorado Futurescience kit for superconductor fabrication. We no longer sell the fabrication kit, so we decided to put these instructions on the Web. We do, however, still sell other superconductivity kits. Since we're making this information available without charge, we can assume no liability for the safety or reliability of the procedure. This procedure was written for High School Science labs; but, of course, it can also be used at colleges and in other settings. Individuals unaffilated with any research laboratory or educational institution have also used this procedure successfully. Unaffiliated individuals, however, may have difficulty obtaining the required chemicals. None of the major suppliers of research chemicals will sell chemicals to individuals. Colorado Futurescience also no longer sells these chemicals. Some larger cities have science stores that do sell small quantities of these chemicals to individuals. Also, some re-sellers of scientific supplies, such as those listed in the classified ads in publications such as Popular Science will sell these chemicals to individuals. One option for the unaffiliated individual with a scientific background is to volunteer to assist a High School Science Department with this project. Many schools are in need of qualified volunteers to assist with science projects.
Colorado Futurescience Good introductory material on superconductors, including instructions for Making superconductors in a High School Science Laboratory, and complete superconductor kits for science educators. http://www.webcom.com/cfsc/
Extractions: Superconductors. We make superconductor demonstration kits and accessory items for science education. Our superconductor products are available directly from Futurescience, Inc. The complete manuals for all of our superconductor kits are now online. THE ACCORD PUBLISHING STORE sells the complete line of calendars, science stuff, children's books, and much more from Accord Publishing. Futurescience compiles the material each year for the Easy Answer Science Calendar , published by Accord Publishing. For an abundance of information on the latest research into the possibilities of a longer, healthier life than most people ever thought possible, see Jerry Emanuelson's free comprehensive manual on the practical applications of scientific research into a
Introduction To Superconductors Copyright 1987,1989, 1999 Colorado Futurescience, Inc. AN INTRODUCTION TO THENEW OXIDE superconductors. by. Jerry Emanuelson. Colorado Futurescience, Inc. http://www.futurescience.com/scintro.html
Extractions: Superconductivity was discovered in 1911 by Heike Kamerlingh Onnes, the Dutch physicist known for his research into phenomona at extremely low temperature. In 1908, Onnes had become the first person to liquify helium. He was investigating the electrical properties of various substances at liquid helium temperature (4.2 degrees Kelvin) when he noticed that the resistivity of mercury dropped abruptly at 4.2 K to a value below the resolution of his instruments. In 1933, W. Meissner and R. Oschenfeld discovered that a metal cooled into the superconducting state in a weak magnetic field expels the magnetic field from its interior. In 1945, the Russian physicist V. Arkadiev first performed the now-classic experiment of using this expulsion of a magnetic field to levitate a small bar magnet above the surface of a superconductor. Advances in superconductivity continued to proceed slowly. During the first 75 years of superconductivity research, the critical temperature (the temperature below which superconductivity is present) was raised by less than 20 degrees . In 1973, a niobium alloy was produced with a critical temperature of 23.2 K. This is still the highest temperature for a metallic superconductor.
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).
404 Error Message The best option for seamless power may be energy storage technologies. Discusses batteries, flywheels, supercapacitors, and superconductors. Includes figuresElectrical Construction Maintenance http://ecmweb.com/ar/electric_success_energy_storage/index.htm
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.
Oxide Physics Research The programme is a collaboration of experimental and theoretical physicists working on the behaviour of correlated electrons in oxide materials. Based in the School of Physics and Astronomy at Birmingham University, United Kingdom. Materials of interest include the high temperature cuprate superconductors, nonFermi liquid physics near quantum critical points, unconventional superconductivity in the ruthanates and heavy fermion behaviour in lithium vanadate. http://www.oxides.bham.ac.uk/
Extractions: Welcome to the web pages of the Oxide Research Programme. The research programme is a collaborative effort between experimental and theoretical physicists, together with material scientists, with the common goal of understanding of the behaviour of correlated electrons in oxide materials. The work is distributed across the collaborating institutions: at the University of St Andrews (School of Physics and Astronomy), at the University of Birmingham (in the School of Physics and Astronomy and also the School of Chemistry) and in the Low Temperature Physics group at the Cavendish Laboratory in Cambridge. We also work with a number of international collaborations. The experimental work is headed by Professor Andy Mackenzie (St Andrews) and the theoretical work by Professor Andy Schofield (Birmingham). What are correlated electrons?
Superconductivity - Uses Of Superconductors Uses of superconductors. The US Department of Energy are actively encouragesthe use of superconductors as energy efficient devices. http://www.chemsoc.org/exemplarchem/entries/igrant/uses_noflash.html
Extractions: Superconductors have many uses - the most obvious being as very efficient conductors; if the national grid were made of superconductors rather than aluminium, then the savings would be enormous - there would be no need to transform the electricity to a higher voltage (this lowers the current, which reduces energy loss to heat) and then back down again. Superconducting magnets are also more efficient in generating electricity than conventional copper wire generators - in fact, a superconducting generator about half the size of a copper wire generator is about 99% efficient; typical generators are around 50% efficient. The US Department of Energy are actively encourages the use of superconductors as energy efficient devices. At the moment, the problem lies with the critical temperature - unless a material is found that can superconduct above 300K, some sort of cooling system needs to be employed, which would be expensive, although companies are developing prototypes - in December 1998, Pirelli Wire built a test 150ft cable that transmitted electricity using high temperature superconducting materials.
Home Page Of Ivan Sergienko Research interests include multiple phase transitions in piezoelectrics and superconductors. http://www.physics.mun.ca/~isergien/
Extractions: I work as a Postdoctoral Fellow for Prof. S. H. Curnoe I am interested in systems displaying multiple phase transitions and also new superconducting states. The symmetry provides certain selection rules for possible orderings. No matter which kind of ordering you study, the general ideas of the phase transition theory proposed by L. D. Landau WORK! So far, I have dealt with ferroelectrics, ferroelastics and superconductors. Please scan through my publication list for details. The selected results are featured below. Mixed-parity superconductivity
Superconductivity - Wikipedia, The Free Encyclopedia Elementary properties of superconductors. superconductors in science fiction.Superconductivity has long been a staple of science fiction. http://en.wikipedia.org/wiki/Superconductor
Extractions: Superconductivity is a phenomenon occurring in certain materials at low temperatures , characterised by the complete absence of electrical resistance and the damping of the interior magnetic field (the Meissner effect Superconductivity occurs in a wide variety of materials, including simple elements like tin and aluminum , various metallic alloys , some heavily-doped semiconductors , and certain ceramic compounds containing planes of copper and oxygen atoms . The latter class of compounds, known as the cuprates , are high-temperature superconductors. Superconductivity does not occur in noble metals like gold and silver , nor in ferromagnetic metals. In conventional superconductors , superconductivity is caused by a force of attraction between certain conduction electrons arising from the exchange of phonons , which causes the conduction electrons to exhibit a superfluid phase composed of correlated pairs of electrons. There also exists a class of materials, known as
Physics News Update Number 683 2, April 29, 2004 by Phil Schewe and Ben Stein MagnesiumDiboridesuperconductors. Magnesium-diboride superconductors http://www.aip.org/enews/physnews/2004/split/683-2.html
Extractions: advanced search Subscribe to Physics News Update Physics News Graphics Physics News Links Archives Number 683 April 29, 2004 by Phil Schewe and Ben Stein Magnesium-Diboride Superconductors Magnesium-diboride superconductors can tolerate twice the usual amount of magnetic field if you spike them with some carbon atoms. The main reason superconducting wires are used as the windings in magnets is not because they save energy, but because they can generate large magnetic fields by carrying large current densities without the resistive heating associated with ordinary copper wire, giving you a much more intense field for the same amount of volume employed in your MRI machine. MgB superconductors, which made their debut three years ago (see Update 530 ), become superconducting at around 40 K, in a colder regime than for the ceramic superconductors (which can be bathed in liquid nitrogen), but much warmer than traditional metal superconductors (such as niobium-tin) which must be cooled in liquid helium. Some consider that the MgB materials (which can be chilled with refrigerators without the use of expensive liquid helium) might be advantageous in some applications where Nb Sn is presently used. For this to happen, the MgB
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
Physics News Update Pressing Forward from Teeth to superconductors. Found headache. But suchphosphorus superconductors might be very useful in spintronics. http://www.aip.org/enews/physnews/2003/split/652-2.html
Extractions: advanced search Subscribe to Physics News Update Physics News Graphics Physics News Links Archives Number 652 September 4, 2003 by Phil Schewe, James Riordon, and Ben Stein Pressing Forward from Teeth to Superconductors Found in teeth and bones as well as fertilizers and DNA, phosphorus is an insulator at room temperature. However, exerting a large amount of pressure on a stable specimen of phosphorus changes its crystalline structure, enabling it to superconduct at temperatures of around 10 K. Exerting even more pressure (2.5 Mbar, about 30,000 times greater than the pressure of clenching your teeth) can transform it again, to a body-centered-cubic (bcc) crystal structure (Akahama et al. Phys Rev B , 1 Feb 2000). Now, Sergey Ostanin of the University of Warwick in the UK and his colleagues have shown that bcc phosphorus crystals achieve superconductivity at higher temperatures, somewhere between 14-22 K. This is still much lower than the temperature of your mouth, even after an ice-cream headache. But such phosphorus superconductors might be very useful in spintronics. For example, they could be help in the construction of a superconducting spin switch, specifically one in which the phosphorus layer would lie in between a pair of ferromagnets, an arrangement that could alter its identity from superconductor to regular conductor (L. R. Tagirov
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 LHC Design Report 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 Configurations ... Tunnel Who's Who Mechanical 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 ...
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: power to the pentaquark old as the m4 planet elegant universe catch an earthquake ... 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.
Ceramics WebBook WebHTS Query Society Journal of Materials Research, MRS Bulletin, and MRS Symposium ProceedingsAmerican Chemical Society CA Selects Oxide superconductors DISCLAIMERS A http://www.ceramics.nist.gov/srd/hts/htsquery.htm
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?
One Step Closer To Superconductors | Csmonitor.com edition One step closer to superconductors. By Peter N. Spotts Staffwriter of The Christian Science Monitor. Call it the 135 K wall. http://www.csmonitor.com/2004/0202/p12s01-stss.html
Extractions: Call it the 135 K wall. What might sound like the end of a torturous foot race is a temperature barrier (135 degrees Kelvin) that scientists have yet to breach in their quest for new materials that, when properly chilled, carry electricity without any resistance. Known as superconductors, these materials hold the promise of smaller, faster computers, smaller and more powerful electric motors, and a more reliable and energy-efficient electrical-utility grid. The goal is to push superconductor operating temperatures higher, so they can work without expensive equipment that keeps them chilled at more than 200 degrees below F. BREAKING THE COLD BARRIER: Deborah Jin, Markus Greiner, and Cindy Regal created a state of matter that could help superconductor research.