A New Family of High-Temperature Superconductors

sciencehabit writes to let us know that physicists are hailing the discovery of a new type of superconductor as a "major advance." The new materials could solve the biggest mystery in condensed matter physics — i.e., how and why cuprate superconductors work — as well as paving the way for practical magnetic levitation and lossless transmission of energy. "God only knows where it will go," says one Nobel Laureate. After the discovery of superconductivity in an iron-and-arsenic compound at 26 kelvin, several Chinese research groups quickly found related materials that are superconducting up to 55K. (Cuprates go as high as 138K; liquid nitrogen boils at 77K.)

Background Information

[explosivejared]

Here (PDF warning) [uni-augsburg.de] is an in depth look at high temperature superconductors, especially the cuprate families, for those not well versed in the subject.

Re:Hot!

[jellomizer]

Well there is a huge difference in the price for using Liquid Nitrogin vs. Liquid Helium. Right now for superconductors used in MRI's they use Liquid Helium at 4k. And they use Liquid Nitrogin as an insolator to protect caseing from cracking. At roughly $1000.00 per leter of Liquid He, Liquid Nitrogin is much cheaper. Anf if they can get to a point where you can maintain superconductivity at Dry Ice level it would cause far more advances in society.

liquid nitrogen 77K is the goal

[spineboy]

A big goal is to get superconductors to work at 77K, because then they can be cooled by cheap liquid nitrogen. Lower than that, you have to use liquid helium(I think) which is quite expensive.

Re:Hot!

[ThreeGigs]

The excitement isn't about superconductivity at 55K by itself. It's got everyone excited because, *finally*, there's something besides cuprates that superconducts above about 33K (which defines high temperature in the superconductor world).

Now, instead of having just one 'family' of HTSC materials to base hypotheses and theories upon, scientists now have TWO. Now they can compare similarities and differences between those two families. This gives them a HUGE boost towards figuring out the exact mechanism involved, plus potential leads on new materials that exhibit similar atomic structure which could also superconduct.

Re:Hot!

[evanbd]

Where do you get $1k/L? A quick google search turns up $3-5 per liter, which is about what I recalled. LN2, of course, is much cheaper -- $0.25 in small quantities, $0.05 per liter or less in very large quantities.

Dry ice is more expensive than LN2, because you have to pay for the CO2, rather than just liquefying air. But if you don't actually need dry ice, then dry ice temps are certainly cheaper to reach than LN2 temps.

Re:US science is dying?

[Anonymous Coward]

If you think China is a poor third world country then you are going to be shocked.
China is mostly a second world country

"First world", "second world", and "third world" are not some ranking of affluence. "X world country" was an old Cold War term. First world nations were those aligned with the West. Second world nations were those aligned with the Soviets. Third world nations were those aligned with neither. Since the fall of the USSR, there is no longer such thing as a second world country.

Third world countries tended to be poor and underdeveloped. Now "third world" has become synonymous with "poor", but it is really a misnomer.

Re:Hot!

[krlynch]

At roughly $1000.00 per leter of Liquid He, Liquid Nitrogin is much cheaper.

You've got the right idea, but your numbers are a bit out of whack ... LN2 is about $0.10/L in large quantity, while LHe is about $3-20/L, with large variation in price around the world (due to constrained supply and large transportation and energy costs). US He is relatively cheap, as we have a few of the small number of high quality sources. In Europe, He is very much more expensive, as they don't have any local, high quality sources. A recent compilation of costs is available here: http://hypertextbook.com/facts/2007/NadyaDillon.shtml [hypertextbook.com]

Helium is so expensive, because it is very entery intensive to liquify, and it isn't commercially extracted from the atmosphere like nitrogen ... there just isn't enough of it to be commercially viable. Instead, it is generally found in pockets underground and "mined". The helium originates as alpha particles in the decay of radioisotopes (mostly Uranium and Thorium), and permeates through the crust. It gets trapped in high pressure gas pockets by impermeable rocks, in the same types of geology that trap natural gas, and is extracted for commercial scale from those pockets. There are only a few global sources where the concentrations of helium are high enough to extract economically.

Re:Hot!

[David Gerard]

All these new materials are ridiculously brittle and difficult to form ceramics, so making coils and so forth is a major PITA and helium actually works out cheaper in practice.

Re:Hot!

[Agripa]

There are superconductors that work above the boiling point of nitrogen though right? Why not use those instead? Do the cost/problems offset the saving in coolant?

My understanding is that their lack of malleability as well as their very low critical current density prevents large scale use.

http://en.wikipedia.org/wiki/YBCO [wikipedia.org]

Re:Superconducting Supercomputers?

[FailedTheTuringTest]

The poster was talking about local heating effects, not global, and while you're right that a few computers won't create a heat island and change the local ecology, there is one sort of local effect that is quite real and well-known all across the Arctic. Any warm structure will heat the ground it is built on slightly, and in the high Arctic where permafrost [wikipedia.org] exists, anything you build (including all buildings and pipelines) has to take this into account or the permafrost melts and the structure sinks. The problem is usually solved by building on piles, or on really thick and heavily insulated foundations (sometimes with heat pipes). I presume the same goes for Antarctic research stations, except of course where a solid-rock site is available.

Liquid Neon as a refrigerant

[billstewart]

Most gasses have boiling points higher than nitrogen's, but there's at least one option between cheap liquid nitrogen and expensive liquid helium, which is liquid Neon [wikipedia.org], which boils at 24.5 kelvin. The Wikipedia article says it's not cheap, but not as expensive as liquid helium, has better refrigeration properties, and is extracted from air rather than rare sources that risk exhaustion.