Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Superconductivity 'fingerprint' found at higher temperatures

A computer-generated representation of the data obtained by scanning a cuprate superconductor in sub-atomic steps. Each cross represents a "Cooper pair" of electrons. At a temperature below 37K (bottom sheet) the pairs are in an orderly arrangement and current can flow without resistance. At a higher temperature the Cooper pairs are still present, but no longer orderly.
A computer-generated representation of the data obtained by scanning a cuprate superconductor in sub-atomic steps. Each cross represents a "Cooper pair" of electrons. At a temperature below 37K (bottom sheet) the pairs are in an orderly arrangement and current can flow without resistance. At a higher temperature the Cooper pairs are still present, but no longer orderly.

Abstract:
New measurements at Cornell have shown that "high-temperature" superconductors may have the potential to go even higher, offering the possibility of creating room-temperature superconductors, or at least superconductors that will work with conventional refrigeration.

Superconductivity 'fingerprint' found at higher temperatures

Ithica, NY | Posted on August 27th, 2009

Such materials could lead to far more efficient electric generators, lossless power transmission and other energy-saving applications.

Superconductors conduct electricity with zero resistance, but only when cooled to very low temperatures. Recently developed materials called cuprates, consisting of copper oxide doped with other elements, superconduct up to temperatures as "high" as 150 kelvins (-123 C or -253 F).

In these superconductors electrons join up in pairs that somehow can move through a crystal lattice without bouncing off of atoms and slowing down. Theory and some experiments have suggested that these "Cooper pairs" are still formed in a temperature range up to 1.5 times the critical temperature at which superconductivity occurs.

But previous measurements were indirect and could be explained in other ways, said J.C. Séamus Davis, the J.G. White Distinguished Professor of Physical Sciences at Cornell and a senior scientist at Brookhaven National Laboratory. The new results show a definitive signature, Davis said. The research, a collaboration among Cornell, Brookhaven and scientists in Japan, is reported in the Aug. 28 issue of the journal Science (Vol. 325, Pg. 1099).

"For two decades people have wondered if [the behavior in this range] is related to superconductivity, and we have proved that it is," Davis said. "I think we have demonstrated very clearly that the electrons are in pairs up to a higher temperature."

Davis and his team worked with a cuprate containing bismuth, strontium and calcium that superconducts when cooled below 37 kelvins (-236 C or -393 F). They used an unusually sensitive scanning tunneling microscope (STM) mounted on massive supports to eliminate outside vibration to scan across a cuprate sample in steps smaller than the width of an atom. An STM scans with a probe so sharp that its tip is a single atom, and measures current flowing between the tip and a surface. By measuring current flow under a range of conditions, the researchers could determine the energy states of electrons below the probe.

The experiment offered serious technical challenges. Thermal motion of the atoms introduces noise in the signal, so the researchers chose an "underdoped" cuprate that superconducts at a very low temperature. To further increase the signal-to-noise ratio, measurements were taken very slowly, taking 10 days to scan a 45-nanometer square, possible only because of the extreme stability of the specially built STM. Special care was also taken in the manufacture of the STM's tiny probes.

"We found that the characteristic signature passes unchanged from the superconducting state into the parent state -- up to temperatures of at least 55 K, or 1.5 times the transition temperature," Davis said. But in that range, the scans showed that the physical orientation of the pairs becomes disorganized or "out of phase." Davis likens superconductivity to a group of dancers lined up for a Virginia reel, but carrying basketballs. If each couple tosses a ball to the next in a regular rhythm, the balls can move swiftly along the line. But if the dancers are scattered around the floor, say doing a polka, the balls will go every which way and make little progress.

"After you pass through the critical temperature at which superconductivity is lost you still have the same fingerprint," Davis said. "The theoretical explanation is that the process of making the pairs survives but the process of aligning them periodically is destroyed. If we could understand why these pairs lose their lockstep, that knowledge would be sufficient to engineer materials that keep that and then we would have high-T superconductors."

The research was supported by the U.S. Department of Energy, the U.S. Office of Naval Research, the U.S. Army Research Office, the Japanese Ministry of Science and Education and the Japan Society for the Promotion of Science.

####

About Cornell University
Once called "the first American university" by educational historian Frederick Rudolph, Cornell University represents a distinctive mix of eminent scholarship and democratic ideals. Adding practical subjects to the classics and admitting qualified students regardless of nationality, race, social circumstance, gender, or religion was quite a departure when Cornell was founded in 1865.

Today's Cornell reflects this heritage of egalitarian excellence. It is home to the nation's first colleges devoted to hotel administration, industrial and labor relations, and veterinary medicine. Both a private university and the land-grant institution of New York State, Cornell University is the most educationally diverse member of the Ivy League.

For more information, please click here

Contacts:
Media Contact:
Blaine Friedlander
(607) 254-8093


Cornell Chronicle:
Bill Steele
(607) 255-7164

Copyright © Cornell University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Evidence mounts for quantum criticality theory: Findings bolster theory that quantum fluctuations drive strange electronic phenomena January 30th, 2015

Everything You Need To Know About Nanopesticides January 30th, 2015

DNA nanoswitches reveal how life's molecules connect: An accessible new way to study molecular interactions could lower cost and time associated with discovering new drugs January 30th, 2015

Crystal light: New light-converting materials point to cheaper, more efficient solar power: University of Toronto engineers study first single crystal perovskites for new solar cell and LED applications January 30th, 2015

Govt.-Legislation/Regulation/Funding/Policy

Evidence mounts for quantum criticality theory: Findings bolster theory that quantum fluctuations drive strange electronic phenomena January 30th, 2015

Nanoscale Mirrored Cavities Amplify, Connect Quantum Memories: Advance could lead to quantum computing and the secure transfer of information over long-distance fiber optic networks January 28th, 2015

Detecting chemical weapons with a color-changing film January 28th, 2015

'Bulletproof' battery: Kevlar membrane for safer, thinner lithium rechargeables January 28th, 2015

Possible Futures

GS7 Graphene Sensor maybe Solution in Fight Against Cancer January 25th, 2015

Nanotechnology in Energy Applications Market Research Report 2014-2018: Radiant Insights, Inc January 15th, 2015

'Mind the gap' between atomically thin materials December 23rd, 2014

A novel method for identifying the body’s ‘noisiest’ networks November 19th, 2014

Announcements

Evidence mounts for quantum criticality theory: Findings bolster theory that quantum fluctuations drive strange electronic phenomena January 30th, 2015

Everything You Need To Know About Nanopesticides January 30th, 2015

DNA nanoswitches reveal how life's molecules connect: An accessible new way to study molecular interactions could lower cost and time associated with discovering new drugs January 30th, 2015

Crystal light: New light-converting materials point to cheaper, more efficient solar power: University of Toronto engineers study first single crystal perovskites for new solar cell and LED applications January 30th, 2015

Tools

Hiden Gas Analysers at PITTCON 2015 | Visit us on Booth No. 1127 January 29th, 2015

Advantest to Exhibit at SEMICON Korea in Seoul, South Korea February 4-6 Showcasing Broad Portfolio of Semiconductor Products, Technologies and Solutions January 29th, 2015

Park Systems Announces Innovations in Bio Cell Analysis with the Launch of Park NX-Bio, the only 3-in-1 Imaging Nanoscale Tool Available for Life Science Researchers January 29th, 2015

2015 Nanonics Image Contest January 29th, 2015

Environment

Iranian Scientists Use MOFs to Eliminate Dye Pollutants January 29th, 2015

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

Magnetic Nanosorbents Able to Eliminate Chemical Contaminants January 19th, 2015

Malaysian Nanotechnology Company Nanopac Innovation Ltd. lists on the NSX January 19th, 2015

Energy

Crystal light: New light-converting materials point to cheaper, more efficient solar power: University of Toronto engineers study first single crystal perovskites for new solar cell and LED applications January 30th, 2015

Los Alamos Develops New Technique for Growing High-Efficiency Perovskite Solar Cells: Researchers’ crystal-production insights resolve manufacturing difficulty January 29th, 2015

Carbon nanoballs can greatly contribute to sustainable energy supply January 27th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE