Physicists May Be One Step Closer To Explaining High-Temp Superconductivity

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Physicists May Be One Step Closer To Explaining High-Temp Superconductivity

Posted by samzenpus on Sunday March 1, 2015 @06:26AM from the it's-getting-hot-in-here dept.

sciencehabit writes For years some physicists have been hoping to crack the mystery of high-temperature superconductivity—the ability of some complex materials to carry electricity without resistance at temperatures high above absolute zero—by simulating crystals with patterns of laser light and individual atoms. Now, a team has taken—almost—the next-to-last step in such 'optical lattice' simulation by reproducing the pattern of magnetism seen in high-temperature superconductors from which the resistance-free flow of electricity emerges.

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Relatively high temp... by garyisabusyguy · 2015-03-01 06:48 · Score: 0, Redundant

So when they talk about high temp semiconductors, it is still around -211F
What does this mean in practical terms?
Is this an easy temperature to maintain?
What techniques or materials could we use to keep that temp?
How does power generation and pulling off waste heat factor into it?
I look at all the heat handlers in a datacenter and wonder, ok what if we step this down a couple hundred degrees

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1. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 06:51 · Score: 3, Insightful
  
  superconductors, not semiconductors, genius.
2. Re:Relatively high temp... by modmans2ndcoming · 2015-03-01 07:00 · Score: 1
  
  Actually, 138 K
3. Re:Relatively high temp... by modmans2ndcoming · 2015-03-01 07:03 · Score: 4, Insightful
  
  Superconductive materials have 0 resistance which means there is no energy lost to heat.
  As for how easy these temperatures are to hold, see your local hospital and ask them how easy it is for them to maintain their MRI machine's superconductive magnets.
  What understanding the underlying properties of super conductive materials allows is for us to perhaps engineer some meta-materials that hold such properties at room temperature.
4. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 07:17 · Score: 1
  
  If there is no energy lost to heat then there is no work being done. You will always have heat buildup to deal with in any system that does something useful. Superconductors do not magically change that; at best they would allow more efficient interconnects. The most exciting use for truly high temperature superconductors, while not as sexy as computers or MRI's, would be in transmission equipment.
5. Re:Relatively high temp... by Przemo-c · 2015-03-01 07:21 · Score: 1
  
  Yeah helium for cooling superconductor inside mri is a bit costly. it wouldbe great if there would be superconductive materials that could be cooled with nitrogen instead of helium.
6. Re:Relatively high temp... by itzly · 2015-03-01 07:21 · Score: 3, Informative
  
  You will always have heat buildup to deal with in any system that does something useful.
  Superconducting magnets are useful, even if they're not doing work.
7. Re:Relatively high temp... by garyisabusyguy · 2015-03-01 07:22 · Score: 0
  
  138 K is -211 F
  According to the omniscient wiki
  http://en.wikipedia.org/wiki/S...
  Either liquid He or two stage mechanical coolers are used to get the superconducting magnet down to 77 K
  They also note that He is in short supply
  So, these new materials, which seem to be able to operate at about twice the temperature of current superconductors (thanks AC above for pointing out mistake)
  What does than mean in terms of cost, maintainability and overall benefit of keeping something at 138 K as opposed to 77 K?
  Does it allow for different techniques?
  Does it allow for wider applications?
  Does it cost less, and if so by a little or a lot?
  
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8. Re:Relatively high temp... by itzly · 2015-03-01 07:22 · Score: 4, Interesting
  
  perhaps engineer some meta-materials that hold such properties at room temperature.
  Doesn't even have to be room temperature. Being able to make a MRI machine using liquid nitrogen instead of helium would be a huge win.
9. Re:Relatively high temp... by hey! · 2015-03-01 07:25 · Score: 2
  
  True, but last time I read up on this their superconductivity broke down when they carried high currents. They're superconductive enough to be useful, for example making very powerful magnets for NMR machines, but not capable of carrying unlimited current.
  
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10. Re:Relatively high temp... by ShanghaiBill · 2015-03-01 07:28 · Score: 5, Informative
  
  138K = -211F
  The key threshold is 77K. Above that, and you can cool with liquid nitrogen. A liter of liquid N2 costs less than a liter of milk. A liter of liquid helium costs about a hundred times as much.
11. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 07:30 · Score: 0
  
  In practical terms it means you need liquid nitrogen, which is fairly cheap.
  Yes, very easy if you have enough liquid nitrogen.
  Keeping the liquid nitrogen topped up, and venting the nitrogen gas.
  The waste heat is vented with the gas, but this needs to be replaced with liquid nitrogen. More heat generated, more liquid nitrogen used.
12. Re:Relatively high temp... by rossdee · 2015-03-01 07:33 · Score: 1
  
  "Doesn't even have to be room temperature.
  We need improvements in cooling so we can have a colder 'room'
  Especialy in summer. In winter you just open a window.
  .
13. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 07:33 · Score: 0
  
  138K > 77K
14. Re:Relatively high temp... by garyisabusyguy · 2015-03-01 07:34 · Score: 1, Redundant
  
  Does this make the proposed superconducting power transmission corridors feasible?
  http://en.wikipedia.org/wiki/E...
  Has anybody proposed a time-to-market for this, or are we still in the infinite loop of '20 years from now'?
  
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15. Re:Relatively high temp... by garyisabusyguy · 2015-03-01 07:36 · Score: 0
  
  Thanks AC, aside from power transmission, are there other technologies which this would enable such as quantum computing (taking a shot in the dark here)?
  
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16. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 07:42 · Score: 4, Informative
  
  Even though there are higher temperature superconductors, and even if room temperature superconductors are discovered, MRI machines will probably continue to use liquid helium. Superconductivity not only stops when a critical temperature is exceeded, but also when critical magnetic fields are exceeded, and the magnetic field limit increases with lower temperature. So a lot of LN2 superconductors are still used with liquid helium, because you then can have more current and hence more magnetic field for using less superconducting wiring. Higher fields for MRI machines mean more options like higher SNR, better resolution, or quicker measurements. I would expect ambient magnetic field MRI equipment (using Earth's magnetic field with sensitive detectors like SQUIDs) would be the direction low cost, non-cryogenic MRI machines to take in the future if room temperature superconductors were found.
17. Re:Relatively high temp... by blue+trane · 2015-03-01 07:47 · Score: 1, Insightful
  
  Remember the assumptions of Thermodynamics?
  The System is continuous. There are no scale, quantum, or relativistic effects.
  The laws of thermodynamics are relevant only within a narrow range of physical phenomena, which we have gotten out of.
18. Re:Relatively high temp... by Immerman · 2015-03-01 08:00 · Score: 4, Insightful
  
  I think you may have misread a bit - cheap liquid nitrogen boils at 77K, making it ideal for pre-cooling/outer jacket cooling. Most superconductors on the other hand only work their magic at substantially colder temperatures, which require much more expensive liquid helium cooling (liquid He is 100s of times more expensive, as I recall).
  High temperature superconductors are those which operate at temperatures above 30K, with the highest I could find reference to operating at 138K - a range which could easily operate with only liquid nitrogen cooling. Such materials start to open the door to realistic superconducting power distribution, etc, but only in a few very specific cases - it's still radically more expensive than normal conductive wire after all. If we manage another 100K or so jump in superconducting temperature we'd start to get into the range of more traditional cooling systems, even if it's still well below freezing (273.15K). At that point the costs for cooling drop enough that superconductors would start to be attractive for a much wider range of applications.
  
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19. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 08:24 · Score: 0
  
  Thermodynamics covers a lot more than a "narrow range" provided you start with statistical mechanics.
20. Re:Relatively high temp... by burtosis · 2015-03-01 08:33 · Score: 1
  
  No superconductor can carry unlimited current. Every one known or predicted has a threshold that, if exceeded, causes a breakdown of superconducting. Under many circumstances of high currents the resulting heat buildup destroys the superconductor.
21. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 08:39 · Score: 3, Informative
  
  The highest temperature superconductor (HgBa2Ca2Cu3Ox(HBCCO) acts at temperatures at or below -140C (-220F). That is still darn cold. Dry Ice sublimates at -78C. What I would consider practical would be around -5C (which means we have 140C to go). Some would want it to be 25C or higher, but you could run a 'national grid' at -5C where "power pumped in" = "power pumped out" without loss. And it would save I2R losses by boatload. Clearly when you look at the number of chemicals and the structure of what they are creating to get to superconductivity, shotgunning it may not be as good as a sound theory of how things work. Every advance gets us closer to a crapload of money and the ability to use electric cars using a power grid similar to what we have now.
22. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 09:05 · Score: 0
  
  Well better hope this doesn't quench
  https://en.wikipedia.org/wiki/...
23. Re:Relatively high temp... by drolli · 2015-03-01 09:10 · Score: 1
  
  That woudl be pretty unrelated. If you use Helium and not Nitrogen, its not due to the critical temp but due to Type I or II supercondutivity.
  Tcs of Superconductors have been far above liquid Nitrogen for 30 years
24. Re:Relatively high temp... by hcs_$reboot · 2015-03-01 09:11 · Score: 1
  
  Including the C temp would be indeed informative ( -135 C )
  
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25. Re:Relatively high temp... by hey! · 2015-03-01 09:24 · Score: 1
  
  This is what I said, but we should be clear there is zero resistive heating *until* the superconductivity breaks down. There is a critical current above which a superconducting wire ceases to superconduct (for complicated reasons).
  
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26. Re:Relatively high temp... by modmans2ndcoming · 2015-03-01 09:45 · Score: 1
  
  Expensive and difficult are different.
27. Re:Relatively high temp... by blue+trane · 2015-03-01 10:09 · Score: 1
  
  And then the "Laws" turn out to be more like suggestions. Fluctuation theorem...
28. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 10:50 · Score: 2, Interesting
  
  The System is continuous. There are no scale, quantum, or relativistic effects.
  Utter rubbish, laddie, quite like that image you linked to. Modern thermodynamics has no such limitations. Go look up negative temperature (hint: you might have heard of such things as lasers) for a fun, discrete, quantum thermodynamic system. Heck, Planck's black body radiation was a nice, discrete, quantum thermodynamic system. Ye might want to resort to a teacher that's been around at some point during the last century or so, next time you argue thermodynamics. Such a one might point you towards such things as Bose-Einstein or Fermi-Dirac statistics and their thermodynamic interpretation. As for relativistic effects, look up thermodynamic models white dwarves, to begin with.
  
  The laws of thermodynamics are relevant only within a narrow range of physical phenomena, which we have gotten out of.
  Conservation of energy (first law) is quite relevant at pretty much any scale that was tested so far. Entropy increase and irreversible processes (second law), same thing (although there are interesting points about it w.r.t. black holes). Third law, entropy goes to a finite (sometimes zero, sometimes not) value as temperature approaches 0K was tested with quantum systems, as those are the only ones relevant at that temperature scale (thermodynamic fluctuations drop below quantum ones).
  Now, the GP has a partial point, the superconducting part of the circuit does no 'useful' work, that does not mean the rest of the circuit doesn't either. Transport is important, as anyone who ever saw a superconducting magnet knows well (those things tend to be hard to transport, too). Thermodynamics gives one an upper limit of efficiency, superconducting wires simply move the efficiency closer to the theoretical limit. Overall entropy of the system increases, even if we manage to constrain it inside the superconductor (well, on the surface, mostly).
29. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 10:59 · Score: 2, Interesting
  
  Tcs of Superconductors have been far above liquid Nitrogen for 30 years
  Yeah, in brittle ceramic form. Something other than cuprates would be nice, preferably something useful ... and not too reliant on rare earths. That's the whole point of the exercise, bloody CuO plane is weird and it's been hard to study, nevermind to make for industrial applications. So they're trying to simulate it, which is quite cool imo. Personally, I'm still betting on AFM insulator effects over Mott insulator ones, but it remains to be seen.
30. Re:Relatively high temp... by king+neckbeard · 2015-03-01 11:00 · Score: 1
  
  and, assuming that we can get roughly equal capacity at more economic temperatures, what kind of range of capacity are we talking about here? Would you be able to power a toaster or a city?
  
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31. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 12:16 · Score: 0
  
  A superconducting magnet would be quantum locking itself. Come to think of it such an object may be able to operate as a near perpetual motion machine.
32. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 12:32 · Score: 0
  
  Who modded this up? Yes you make assumptions when teaching an intro level thermo course, or especially with engineering thermodynamics where quantum and relativistic effects are not relevant 99.9% of the time. But thermodynamics of quantum systems has been worked out a long time ago, and is covered in undergraduate level courses. There is also relativistic thermodynamics. They same basic principles hold and are very general to many other systems, even if the math is a bit harder to do.
33. Re:Relatively high temp... by BeyondPale · 2015-03-01 13:29 · Score: 1
  
  I'm a bit surprised that the HTSC cables actually exist, as evident from the quoted wikipedia article. The high-temperature superconductors are ceramics, so normally you either produce a single crystal (not practical beyond a few millimeters in size, very expensive), or you compress a bunch of small superconducting grains into a solid object. Clearly, you would not be able to bend a cable made of such material too much, as it would simply break, and the contact areas between grains would always have higher resistance, limiting the amount of current such cable may carry. I would be curious to learn how these problems are solved in existing cables, but the articles describing them are pretty light on details (not surprisingly).
34. Re:Relatively high temp... by JoeMerchant · 2015-03-01 14:12 · Score: 2
  
  Um, yeah, that's what they do in MRIs. Only have to energize it and keep it cool. They get really ticked if they have to turn it off - very time consuming and expensive to turn it back on again.
35. Re:Relatively high temp... by Greyfox · 2015-03-01 15:18 · Score: 1
  
  Goddamn interns keep inhaling the helium to talk like the Chipmunks.
  
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36. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 15:58 · Score: 0
  
  cheap liquid nitrogen boils at 77K,
  But if you can get 138K superconduction, then you can use even cheaper liquid air (boils at 82K).
  Liquid nitrogen would be great for MRI machines, but liquid air would allow for more general uses where you can't afford to ship a purified liquid just for cooling. Air itself is of course plentifully available.
37. Re:Relatively high temp... by tlhIngan · 2015-03-01 18:25 · Score: 3, Interesting
  
  So when they talk about high temp semiconductors, it is still around -211F
  What does this mean in practical terms?
  Is this an easy temperature to maintain?
  What techniques or materials could we use to keep that temp?
  How does power generation and pulling off waste heat factor into it?
  A "low temp" superconductor relies on liquid helium to keep it cool (approx 4K). A 'high temp" superconductor relies on liquid nitrogen to keep it cool (77K).
  Liquid nitrogen is stupidly cheap - tons of places use liquid nitrogen for a lot of non-superconducting purposes including packaged food preparation, cooling, experimentation (a lot of "cryo" experiments use liquid nitrogen, including the ever popular frozen rose, frozen banana and other science demonstrations).
  In fact, to get rid of a small dewar of liquid nitrogen, it's usually just dumped on the table after the demo is done creating a nice effect. A more controlled evaporation is simply leaving the lid off and letting it boil off naturally.
  No one keeps stuff cool by liquifying nitrogen onsite. Instead, they just have Air Liquide and similar companies come by every week or so and top off the cryo tank. The cryo tank provides the supply of liquid nitrogen that's needed for the equipment (MRI machines use it in superconducting magnets). Most labs have it available freely as well.
  Liquid helium is much more expensive. Liquid nitrogen is so cheap that having it transported and even any wastage is considered "meh". Hell, schools probably buy way more than they need simply because to make it worthwhile you end up with a huge dewar of it.
38. Re:Relatively high temp... by Anonymous Coward · 2015-03-01 22:38 · Score: 0
  
  For most large system they're probably laws... :)
39. Re:Relatively high temp... by Immerman · 2015-03-02 03:05 · Score: 1
  
  I believe one of the reasons liquid nitrogen is a preferred cooling liquid is that it's chemically inert. Do they even sell liquid air? I've never heard of it. I would suspect liquid oxygen might be nastily corrosive, and quite possibly explosive since it will likely boil out of solution before most the rest.
  Ah yes, quite. From Wikipedia:
  
  Liquid oxygen is also a very powerful oxidizing agent: organic materials will burn rapidly and energetically in liquid oxygen. Further, if soaked in liquid oxygen, some materials such as coal briquettes, carbon black, etc., can detonate unpredictably from sources of ignition such as flames, sparks or impact from light blows. Petrochemicals, including asphalt, often exhibit this behavior.
  
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40. Re:Relatively high temp... by Anonymous Coward · 2015-03-02 06:13 · Score: 0
  
  cheap liquid nitrogen boils at 77K
  What temperature does expensive brand-name liquid nitrogen boil at?
41. Re:Relatively high temp... by Anonymous Coward · 2015-03-02 08:05 · Score: 0
  
  "Cable" is a bit of a misnomer. HTSC cables are typically made of the precursors to the ceramics in metalic or powder form encased in a sheath (usually of metal). Once the "cable" is wound in place or run you can then fire it in a kiln to turn the interior into a superconductive "cable" in the shape desired.
42. Re:Relatively high temp... by Immerman · 2015-03-02 10:53 · Score: 1
  
  Still 77k, but it's much cooler.
  
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Almost nearly next-to-there by Anonymous Coward · 2015-03-01 07:24 · Score: 0

"almost—the next-to-last step"
So glad we're getting ready for the pre-antepenultimate development in superconductivity!
Re:that was on season 1 of ancient aliens by Anonymous Coward · 2015-03-01 08:17 · Score: 0

Who upvoted this moron?
Ancient Aliens is the worst kind of unscientific trash.
Physics Question? by Anonymous Coward · 2015-03-01 09:21 · Score: 1

If we can get a superconducting magnet in the Lagrange point of Mars, would it deflect the solar winds such that a cone would form around Mars, thereby making an atmosphere feasible in the absence of a global electromagnetic shield?
Would that be a very interesting application of superconductors?
1. Re:Physics Question? by Anonymous Coward · 2015-03-02 07:49 · Score: 0
  
  Nope.
superconductivity origins by epwpixieqneg1 · 2015-03-01 10:06 · Score: 1

Probably whould be helpful in all of this, if people go and read what the person, who predicted theoretically the superconductivity, or super-resistivity as he named it, actually said. So, basically, go and read Heaviside's 2 voluem "Electrial Papers", in order to understand the mass the current physics/electrical engineering is. And no, this has nothing to do with Maxwell, as Heavisde in his work, corrected and inanced Maxwell's ideas, but has to do with some subsequent characters in the sicentific history and their religious followers.
It was a joke. Did nobody get that? by Qbertino · 2015-03-01 10:54 · Score: 1

"explaining" superconductivity? Hum? "explain" ... get it?

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1. Re:It was a joke. Did nobody get that? by garyisabusyguy · 2015-03-01 11:03 · Score: 2
  
  Must be funnier in German
  
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2. Re:It was a joke. Did nobody get that? by Anonymous Coward · 2015-03-01 13:26 · Score: 0
  
  I get it. I was going to comment "Great - finally someone can explain it to me." But I didn't. Oh, I suppose I just did.
Re:that was on season 1 of ancient aliens by Anonymous Coward · 2015-03-02 03:02 · Score: 0

lol what a retard you are.
Space by Anonymous Coward · 2015-03-02 07:15 · Score: 0

Is it possible to get a cable in space down to those temperatures using passive cooling? I seem to remember there is a way to shift orbit or generate power using orbiting conductive cables.
1. Re:Space by Immerman · 2015-03-02 10:59 · Score: 1
  
  Hmm... I suppose if you were in a polar orbit, whose plane was being gradually rotated to stay perpendicular to the sun, you could conceivably keep one side of the cable in perpetual shadow for radiant fins, and heavily mirror the sun-facing side. The photon pressure might generate enough torque to coplicate the issue significantly though. Then again, if you shaped that mirror *just* right, maybe you could get the thing to self-stabilize with its orbit facing the sun, so that near-continuous course correction wouldn't be necessary.
  
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