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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.)
Here (PDF warning) is an in depth look at high temperature superconductors, especially the cuprate families, for those not well versed in the subject.
I got a catholic block.
The "firestorm" was ignited by the discovery of cuprate semiconductors, which "have critical temperatures in excess of 90 kelvin"[1], which is above the temperature of liquid nitrogen.
[1]http://en.wikipedia.org/wiki/Superconductor
www.timcoleman.com is a total waste of your time. Never go there.
This is assuming standard pressure, of course. Any advancement in the operating temperature of a superconductor would make it easier to pressurize a system in order to bring its operating temperature up.
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.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
as well as paving the way for practical magnetic levitation
Awesome! Can't wait for my superconductor magnetic levitation bed!
You just got troll'd!
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.
..........FULL STOP.
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.
1. "High T_c" is a technical term. Indeed, 55 kelvin is "high" (though not as high as the record for cuprates). You have to compare it with the typical T_c for metals (a few kelvin). The difference is between liquid helium temperatures and liquid nitrogen temperatures (which cuprates have reached already and perhaps the new compounds also will).
2. More improtantly, this will ignite a "firestorm of research". You see, we don't have a good model of high T_c superconductivity (unlike the BCS model for metals). Having several different superconducting systems will help theorists isolate the significant features of the system from the less significant ones.
3. Seeing superconductivity in a totally new material is exciting. This is interesting basic research even if today we dont' have a practical application. If we don't do the research we'll never get to the practical stage.
The article specifically mentions 138 kelvins as the highest temperature where cuprates still hold on to superconductivity. That's roughly -115 degrees celsius. This greatly increases the viability of the material by greatly reducing the energy required to hold it at a critical temperature. Think about the wide extent to which liquid nitrogen is used.
Currently we are in the stage of trying to understand just what exactly is going on at the particle level. Once we move past this research stage (disclaimer: it's been going on for twenty years), the possibilities these materials provide are pretty much endless.
I got a catholic block.
Oh, say does that Star-Spangled Banner entwine / The myrtle of Venus with Bacchus's vine?
It is news not because of any new temperature records, but because of the fact that these are the first superconductors outside of the cuprate family to exhibit high critical temperatures.
This is an entirely new family from the cuprates. The cuprates started much lower too. Also, even if this family never compares to the cuprates in performance, the behavior of this new family could shed light on the (relatively unknown) mechanisms of cuprate superconductivity, allowing for that family to be developed further.
retrorocket.o not found, launch anyway?
Yeah, how are we going to 'fend for ourselves' without superconductors? :O
which is totally what she said
If you think China is a poor third world country then you are going to be shocked.
China is mostly a second world country, isn't very poor(the USA is spending trillions there), currently is almost able to duplicate just about every technologically advanced device being built.
there was a chinese company called NEC which duplicated the Real NEC's tv's poorly but close enough to work for several years before they got caught.
While it will be another 5-10 years China is rapidly building up technology, science, and math. They have the manpower power and will, just like japan had 30 years ago. Remember 40 years ago the Japanese only made junk, 20 years later they owned the electronics market, and 10 years after that had some of the best selling cars out there.
i thought once I was found, but it was only a dream.
there was a chinese company called NEC which duplicated the Real NEC's tv's poorly but close enough to work for several years before they got caught.
Not only did they make the TVs, but apparently they also dealt with real NEC plants on a regular basis, and due to poor organization, nobody caught on.
Klingon programs don't timeshare, they battle for supremacy.
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.
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.
You've got the right idea, but your numbers are a bit out of whack
Helium is so expensive, because it is very entery intensive to liquify, and it isn't commercially extracted from the atmosphere like nitrogen
There's 3 in Chicago that replaced either 7 or 11 oil cooled copper lines. The power company actually made money on that while increasing capacity I hear. They pulled out and sold the copper to cover the cost of the conductors. The LN cost is covered by reduced heat losses and the elimination of the need to pump & cool the oil.
I don't read AC A human right
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.
http://rocknerd.co.uk
Where do you get $1k/L? A quick google search turns up $3-5 per liter
Well duh! He's talking about MEDICAL liquid HE which is obviously much more expensive than normal liquid HE. Ever get a bandaid put on at a hospital?
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
We're nowhere near being able to actually heat the planet to any significant degree. Run the computations on how much energy the planet receives from the Sun every day, compare with the total energy generated by humanity in a day.
You don't need to worry about "damaging" the Antarctic by running some computers and dumping the heat out into the local environment. Heat just dissipates, and since it's at a rate proportional to the difference between the temperatures, it goes away faster the more you try. (That's the fundamental reason why we can't directly heat the planet, because even if we did, it would just radiate away.) You need to worry about the stuff that doesn't dissipate.
I believe you mean -135 degrees celsius.
That last twenty degrees is what keeps Minnesota from superconducting in winter.
Never shake hands with a man you meet in a fertility clinic.
Hanging on to our lead, on the other hand, is doubtful: "Cited papers first-authored by Chinese scientists -- an important indicator of scientific creativity -- increased by 25.3 per cent in 2006, and the number of times they were cited increased 28.3 per cent. However, China remains thirteenth in terms of total citation numbers." At that rate, China won't be in 13th for long.
From the global perspective it doesn't matter; all this means mankind as a whole is simply progressing much faster now. But from the US nationalist perspective, this definitely decreases our ability to compete for increasingly scarce natural resources. We've already seen this occur drastically in the price of oil.
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 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.
The big deal with this discovery isn't that the possibilities the new materials they've found are endless. They actually underperform what we already have. It's that we don't understand how what we have (cuprate superconductors) works, but if we did, we could potentially find much higher-temperature superconductors. This gives us a key to help understand high temperature superconductivity. And the possibilities of high-temperature superconductors would be endless (assuming they could be made affordably).
I'll BUILD someone to replace you. Some kind of gamma-powered monster, with a heart as black as coal!
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, 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.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks