Image: PHOTOGRAPH BY JAMIE CHUNG AND STYLING BY BRIAN BYRN
In Brief
- Conventional superconductors carry electric currents without energy losses but only when cooled to near absolute zero. Copper oxide, or cuprate, superconductors shattered a long-standing temperature barrier in the late 1980s, but adapting them for industry has been challenging.
- The cuprates seemed to be unique until 2008, when physicists found that compounds known as pnictides (pronounced “nik-tides”) also superconduct well above absolute zero.
- Study of the pnictides might help scientists to finally understand how the cuprates work and to perhaps learn how to make room-temperature superconductors.
Hideo Hosono's research group at the Tokyo Institute of Technology was not looking for a superconductor in 2006. Rather the team was trying to create new kinds of transparent semiconductors for flat-panel displays. But when the researchers characterized the electronic properties of their new substance—a combination of lanthanum, oxygen, iron and phosphorus—they found that below four kelvins, or –269 degrees Celsius, it lost all resistance to carrying an electric current; that is, it superconducted.
Although 4 K is far below the current laboratory record of 138 K (let alone the holy grail of “room temperature,” or about 300 K), experimentalists with a new superconductor are like yachtsmen with a new boat design. The sailors want to know how fast they can make it go; the physicists, how hot any variant of the material can superconduct. Superconductors’ uses in industry are hobbled by the need for expensive, complicated, space-hogging cooling systems. Any increase in operating temperature could ease those drawbacks for existing devices and make completely fresh applications technically and economically viable. Engineers envisage, for instance, lossless power cables carrying huge currents and compact superstrong magnets—for magnetic resonance imaging, levitated trains, particle accelerators and other wonders—all without the exorbitant expense and trouble of the liquid-helium cooling systems required by the old, cold, conventional superconductors.
This article was originally published with the title An Iron Key to High-Temperature Superconductivity?.
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7 Comments
Add CommentI understand the "Holy Grail" is to develop a material that has no energy loss, aka superconducting, at ambient temperature. I think the focus is so narrow on this goal that a golden egg could be overlooked. I think it would be a major acheivement to use this knowledge to develop a material that is not necessarily superconducting, but more efficient at ambient temperature.
Reply | Report Abuse | Link to thisImagine if standard high-power electrical lines were more efficient? Imagine if simple electronic components could be made more efficient? If those materials were made to reduce energy loss by 10%, the savings could be substantial financially and environmentally.
This is pure speculation, but I see potential to "land on the moon" that appears to overshadowed by concept that we have to "reach the stars" to be successful.
At low temperatures the superconductivity (SC) is affected by spin and phonon interactions, but I do believe, at high temperature SC is completely EM force driven, so it doesn't depends on type of material, but geometry only, as R?'s equation illustrates.
Reply | Report Abuse | Link to thisIMO electrons are attracted to hole stripes, so they get more compressed here and they behave like chaotic fluid or gas exhibiting a collective motion, which isn't affected by lattice geometry. http://aetherwavetheory.blogspot.com/2008/11/awt-and-quest-for-ht-superconductivity.html
Interesting aspect of this model is, it predicts the formation of SC phase even outside of material at the case, when electrons are attracted to hole stripes bellow surface, as prof. J. Prins has revealed accidentally. This opens possibility in artificial fabrication of SC phase by charge gradient created on surface of heavy duty insulators like diamond or boron nitride just by squashing of electron gas here.
one minor mistake in the statement "The limits of that region show that if the doping is too low or too high, the material does not superconduct even at absolute zero."
Reply | Report Abuse | Link to thisAbsolute Zero can not be achieved. The third law of thermodynamics. Hence, there is no "at absolute zero".
i think there should be an effort to apply the node structure of nerve cells in the brain to electrical transmission...they pass an electric signal extremely fast and efficiently...although i know this is a bit round the bend from what this article is discussing.
Reply | Report Abuse | Link to thisThis is exactly the kind of article that I come to SA for. Thanks.
Reply | Report Abuse | Link to thisThat's not a mistake. It's a statement of how absolutely impossible it is to create superconduction in that sample. They're saying that even IF they could get to 0K, it wouldn't be superconducting.
Reply | Report Abuse | Link to thisLet's not get so caught in the weeds that we miss the big picture, eh?
Where the FeAs is doped to optimum it reverts to its symetrical shape. This would suggest that the material forms 'layers ' of tetrahedrons, analogous with the 'sheets' of cuprate. Perhaps the Cooper pairs migrate through the layers. Perhaps the 'condensation' of the tetrahedrons by the doping afford some sheilding or may generate a sufficiently strong charge to deflect the magnetic field around it.
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