Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanoscale imaging reveals unexpected behaviors in high-temperature superconductors

31.05.2007
Recent discoveries regarding the physics of ceramic superconductors may help improve scientists' understanding of resistance-free electrical power.

Tiny, isolated patches of superconductivity exist within these substances at higher temperatures than previously were known, according to a paper by Princeton scientists, who have developed new techniques to image superconducting behavior at the nanoscale.

Superconductivity, the ability to carry electrical current without resistance, could revolutionize electrical power transmission if the property ever appeared in a material at close to room temperature. Even the so-called high-temperature ceramic superconductors discovered two decades ago must be cooled to more than minus 100 degrees Celsius to function.

Using a special customized microscope, the Princeton team has discovered that traces of superconductivity remain present inside these ceramic materials even when they are warmed up above the critical temperature where they lose their resistance. Though the entire sample is too warm to exhibit superconductivity, disconnected regions within it possess Cooper pairs -- the coupled electrons that carry current through a superconductor -- which previously were only known to appear below the critical temperature at which a material superconducts.

The regions are only a few nanometers wide, but they appear in some materials at up to 50 degrees above the critical temperature. Ali Yazdani, senior author of the research paper, said that understanding why these minuscule patches of superconductivity exist at higher temperatures -- and how to create a material that exhibits the property everywhere -- may be the key to enhancing superconductivity.

"Our measurements show that Cooper pairs survive in local patches of the material at temperatures far above the critical temperature," said Yazdani, a professor of physics at Princeton. "Within these tiny regions, there are particular arrangements of atoms that favor formation of electron pairs at very high temperatures. These patches are a precursor to superconductivity and important to enhancing it."

The paper appears in the May 31 edition of Nature. Other members of the research group are Princeton graduate students Kenjiro Gomes and Aakash Pushp and postdoctoral fellow Abhay Pasupathy, as well as Shimpei Ono and Yoichi Ando of the Central Research Institute of Electric Power Industry in Tokyo.

For more than two decades, scientists have worked to explain and enhance the performance of copper-oxide based ceramics, which two decades ago were discovered to superconduct at temperatures far warmer than any other known materials -- though still requiring temperatures that are quite chilly by human standards. High-temperature superconductivity in ceramics has defied a widely accepted explanation and is considered one of the major puzzles in physics.

The key to the puzzle is to determine how electrons, which are negatively charged and normally repel one another, mysteriously change their attitude toward each other and form Cooper pairs. Below the critical temperature, the pairs form everywhere in a material, and can then act in concert as a "superfluid" to carry electric current through it without resistance.

"In lower temperature superconductors, electrons pair up and form a superfluid at the critical temperature -- end of story," Yazdani said. "In ceramics, however, our team is finding that electron pairing occurs over a wide range of temperatures, and their pairing is a function of highly localized chemistry in the sample, often in patches only a few atoms wide."

Investigation on this tiny scale was made possible by a state-of-the-art scanning tunneling microscope the Princeton team designed especially to map superconducting properties on the scale of single atoms while they changed the temperature. The team was able to apply their technique systematically to a large number of high quality copper-oxide superconducting samples.

Unlike an optical microscope that uses light to magnify, the scanning tunneling microscope uses a beam of electrons from a sharp tip to image the sample. The beam served a double purpose for the experiments: Not only does it provide images of a sample down to scales of just a few atoms wide, the beam also is capable of breaking apart electron pairs if it is energetic enough. By varying the energy of the electron beam, the team was able to determine whether pairs had formed in a given spot within the material.

"We spent about two and a half years looking at many different samples at different temperatures to decipher the story," Yazdani said. "We were motivated to search for pairing at high temperatures because of the work of others, most notably that of my colleague Phuan Ong."

The researchers hope to use their experimental results to shed light on what controls the pairing temperature on the atomic scale in ceramic superconductors, and also to determine what limits the Cooper pairs' ability to get their act together to superconduct.

"This type of precision experiment performed while varying temperature gives us a new window into the complex problem of ceramic superconductors," Yazdani said. "If we can figure out the details of what is happening at these local patches within the samples, it might be possible to construct a material that performs better overall."

Such an accomplishment might revolutionize technology for the power industry, said Mike Norman, a physicist in Argonne National Laboratory's Materials Science Division, who was not affiliated with the research.

"If we could raise the critical temperature by making the sample more homogeneous, then superconductivity's application to day-to-day technologies, such as power grids, becomes much more realistic," Norman said. "The nice thing with superconductors is that there is no power loss, so they could be a major player in 'green' and 'efficient' technologies for power transmission."

Chad Boutin | EurekAlert!
Further information:
http://www.princeton.edu

More articles from Physics and Astronomy:

nachricht New type of low-energy nanolaser that shines in all directions
18.12.2018 | Eindhoven University of Technology

nachricht NASA research reveals Saturn is losing its rings at 'worst-case-scenario' rate
18.12.2018 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Data storage using individual molecules

Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.

Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...

Im Focus: Data use draining your battery? Tiny device to speed up memory while also saving power

The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.

Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Physicists found a correlation between the structure and magnetic properties of ceramics

18.12.2018 | Physics and Astronomy

Unique insights into an exotic matter state

18.12.2018 | Physics and Astronomy

Physicists studied the influence of magnetic field on thin film structures

18.12.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>