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High-Temperature Metal Superconductor Beckons
drkrypton writes: "The Globe and Mail is reporting on a new metal which has a superconducting temperature of -234 C or approx. 39 K. While this is still much colder than some ceramic superconductors (which have superconducting temperatures of around -113 C or 160 K) it still may have some ramifications in electronics. Hey, I triple dog dare you to lick it." Perhaps it will one day be routine to start a computing session by dumping in some liquid nitrogen onto a yet-higher-temperature superconducting CPU.
Bill - aka taniwha
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Bill - aka taniwha
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Leave others their otherness. -- Aratak
As to those superconduction toroids, yeah, coolant failure could be, um, interesting.
Bill - aka taniwha
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Bill - aka taniwha
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Leave others their otherness. -- Aratak
You cannot have a material that is both superconducting =and= semi-conducting.
(Superconductors are essentially linear motors at the electron scale.)
Now, it =WOULD= be possible to develop valves that used superconductors, at comparable scales to semi-conductors, as you would essentially have electron streams that you can direct.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
I can't quite picture a superconducting semiconductor in my head. Would such a chip just have superconducting interconnections? How does it work?
If I remember how a transistor works, it would be rather difficult to make one out of a superconductor. Essentially, the idea of increasing the conductance of a stretch of material by applying a voltage at a gate and thus drawing charge carriers into the area to conduct doesn't work where there is no significant resistance regardless of applied gate voltages. In fact the whole CPU would just be one open circuit.
The usual approaches are to either make wiring superconducting (reducing resistive losses a bit), or to use devices other than transistors to perform the switching (a few alternatives exist).
I've linked to my personal favourite method in another post in this article (click "user info" to find it).
There's also the problem of superconductors breaking down in strong magnetic fields, which renders them useless for high-field applications. High-temperature superconductors are especially bad for this.
I disagree. Most modern HTC's have a property called 'flux pinning' Under high magnetic fields, the superconductor allows the magnetic field to recide in small 'tubes' within the superconductor. these tubes run through impurities in the ceramic, (which is non superconducting in any event) and is surrounded by supercurrents that keep the field lines in place. as long as the circular currents is not so hing as to dissallow superconductivity, the bulk of the superconductor behaves as any normal one, that is it is superconducting.
The problem is that breakdown (caused by these flux tubes widening until they meet) *still* occurs at a much lower field strength in type II than in very cold type I superconductors. The strongest superconducting magnet I've ever heard of was an 8-T liquid helium-cooled magnet designed for use in a particle accelerator. If I understand correctly, breakdown for known type II materials is closer to 1 T.
At least one of the referees produced a nice, thoughtful, 2-paragraph report; I don't have any information on the other report. 24 hours is plenty of time to read and evaluate clear and careful experimental research of this sort. We do have some other papers in process on this that are going to take longer to get published since the experimental or theoretical analysis for them is not so cut and dried.
Energy: time to change the picture.
http://www.octools.com/articles/submersion/submers ion.html
Cooling with Fluorinert and liquid nitrogen. If only the Fluorinert wouldn't gel up, it would be perfect:)
High-speed Road Trip (18.000KPH)
According to this article from the LANL e-prints server, MgB2 appears to be a phonon mediated BCS superconductor. Of course, since the initial discovery was only a few weeks ago, it is hard to say.
seems to have disappeared even from the "older stuff" area. weird.
All your event are belong to us.
Perhaps it will one day be routine to start a computing session by dumping in some liquid nitrogen onto a yet-higher-temperature superconducting CPU.
We can only dream timothy, we can only dream...
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python -c "x='python -c %sx=%s; print x%%(chr(34),repr(x),chr(34))%s'; print x%(chr(34),repr(x),chr(34))"
"My ic2 liquied H2 chip can quick your wimpiums P10-ICE's ass" -joy-
"Science is about ego as much as it is about discovery and truth " - I said it, so sue me.
Well, to be honest I doubt that we'll reach room-temp or higher superconductors any time soon (== next hundred years or so). How ever, I suspect that in the next 20-50 years we'll discover a superconductor whose critical temperature is reachable with common industrial refridgerants (like say -40 C instead of -113). This is an easier goal to reach energetically and would open the field to industrial applications like the cool plasma deposition things the other poster was speaking of.
I did a little research into this field a few years back in a special topics class (as a chemist). My impression was that superconducting compounds (I was studying the Yttrium-Barium-Copper-Oxide family) were superconducting by virtue of "channels" forming through the crystalline structure that had surrounding electron densities just right such that free electrons could flow "down" them with 0 resistance, and that since the surrounding atoms "wiggled around" too much at T > Tcrit, the "channels" were disrupted. Or something. I was a chemist, and a freshman, so I wasn't exposed to a lot of the real underlying theory.
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The other reply by Mr. Currie is very correct. Small additional note: really cold metals still have really low resistance, even if it ain't exactly zero. :-) So unless by T > Tcrit you mean T = 500 K or something, it probably won't die horribly. I'd guess you'd see increasing glitchiness as T rose, leading to total system failure. So you'd have functional warnings besides temp alarms (much like a computer that's overclocked too much now).
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Depending on wiring self-inductance there could be a lot of energy stored on the circuit. If you try to change the current circulating through an inductor there will appear a voltage drop that's inductive, not resistive. At a certain point when temperature rises, such a computer could spit out a lot of sparks.
There has been designs for energy storage in large superconducting inductors. As a safeguard against cooling failure, one such design enclosed the inductor in an underground aluminum enclosure. As long as the inductor is cooled below Tc, the aluminum is effectively an insulator compared to the superconductor, since its resisitivity is small but finite. But if the inductor lost its superconductivity, the current would start circulating through the aluminum and would be dissipated by heating, possibly melting, the aluminum. That's why it was designed to be underground.
#universal_mind caused a segfault at 0x654gfde55487d8ec
brain dumped
#rm brain
#universal_mind -load next_victim.brain
#universal_mind caused a...
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
Yeah, it has always paid off to be early adopters of new technology. I think I can wait for the first bugfixes, you go first!
With a XHTS (eXtremely High-Temp Superconductor: read, can take a Saharan summer and still have less than 4 x 10^-25 ohms resistance), you could:
:) )
1. With a sufficient cooling system, your computer's current drain would drop to, maybe an amp. (Hey, the hard drive's gotta get its juice from somewhere!)
Maybe in the near future, if we get HTS's up to 0 Celsius, we could read about projects to wire your freezer and motherboard together.
2. Train tracks could be dual-used as power distribution. (Nice thought that the L would also be the thing juicing up my home entertainment rig. On second thought, maybe not
Added bonus of an XHTS maglev: MUCH lower maintenance costs. Few to nil moving parts means less wear and tear.
The electric company and the public transit authority save oodles of cash.
3. The cost of an MRI would drop. MRI's use superconducting solenoids to produce the immence magnetic fields needed to produce those lovely polychrome images of the inside of your cavesa.
4. Again, thanks to lower-maintenance superconducting solenoids, high-temp fusion is a step closer to reality.
just thinkin' out loud
d.valued
Ruling The World, One Moron At A Time(tm)
"As Kosher As A Bacon-Cheeseburger"(tmp)
I used to be someone else. Now I'm someone better.
Real life is underrated.
it's NOT informative it's DIS-informative and the person who posted it dosent have a clue, sorry to say.
"Unfortunately, cooling something to 1K will require something along the lines of laser cooling in order to achieve, and this turns out to not be very practical."
uhh, no. optical molasses type laser cooling only works for a handfull of atoms at once and only when in the gaseous state.
"Superconductors with a very low critical temperature cannot conduct much current before they exceed their critical energy level and "go normal"."
uhm no. type I superconductors which have low Tc's conduct huge amounts of current and withstand large magnetic fields(read MRI nobium electromagnet wire)
"Useful superconductors are more in the line of HTC's, high temperature superconductors"
not really. metal superconductors are used far more often and cooled to 4K with Liquid He. ductility of the metal superconductors beats brittle high temperature capable ones.
"If I recall correctly, the highest published HTC was around 175K"
no the highest Tc is 135K for a mercury based ceramic.
"Superconductors aren't too useful for their property of not conducting current, since they have a critical maximum current level anyway."
what? im assuming you meant their ability to conduct without resistance and not high resistance, in which case you'd better check your sources because thats just about all theyre ever used for in commercial applications.
"cooled by liquid helium, which is somewhere down on the order of 10K"
liquid He is at 4K.
". They are mostly used for their diamagnetic properties (they repel magnetic flux lines). This is the basis for how an MRI works"
no, it dosent matter that the nobium wire in the MRI machine is a perfect diamagnet because no one cares about that property in an MRI. the superconducting Nb is used to more easily create a high magnetic field to flip the spins of protons in your body.
- "Hear that?! The percolations are imminent! Cease your ingress!"
I didn't see one yet so I figured I'd do it...
-234 C = -389.2 F
C=Celsius/centigrade: Of or relating to a temperature scale that registers the freezing point of water as 0 and the boiling point as 100 under normal atmospheric pressure
F=Fahrenheit: Of or relating to a temperature scale that registers the freezing point of water as 32F and the boiling point as 212F at one atmosphere of pressure.
K=kelvin: A unit of absolute temperature equal to 1/273.16 of the absolute temperature of the triple point of water. This unit is equal to one Celsius degree.
superconducting: displaying properties of superconductivity: The flow of electric current without resistance in certain metals, alloys, and ceramics at temperatures near absolute zero, and in some cases at temperatures hundreds of degrees above absolute zero.
absolute zero: The temperature at which substances possess no thermal energy, equal to -273.15C, or -459.67F
ceramic: Any of various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing a nonmetallic mineral, such as clay, at a high temperature.
lick: To pass the tongue over or along
//m
Instead there is a device called a Josephson Junction that can switch at terahertz frequencies.
Check out the Scientific American article.
IMO Josephson Junctions would make for a great CPU!
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"The Leidenfrost effect rocks. One of my physics profs knew a guy who used to do demonstrations for grade school kids. Part of his act was to put a bit of liquid nitrogen in his mouth, then spit it back out. No harm was done as long as he spit it out quickly. One time, though, he accidentally swallowed it. Nothing got frozen, but the resulting belch was one for the record books.
Bugrit! Millenium hand and shrimp!
Superconductors are, as the name implies, conductors. Conductors (unlike semiconductors) have a conductivity that is a maximum at low temperatures, and decreases with increasing temperature (the opposite of semiconductors). Superconductors are a class of materials that conduct with zero resistance (i.e., infinite conductivity) below some threshold temperature. Virtually all conductors become superconductors at a low enough temperature (~0 K). High-temp superconductors have a threshold temperature significantly higher than 0 K.
"That's not even wrong..." -- Wolfgang Pauli
If I remember how a transistor works, it would be rather difficult to make one out of a superconductor. Essentially, the idea of increasing the conductance of a stretch of material by applying a voltage at a gate and thus drawing charge carriers into the area to conduct doesn't work where there is no significant resistance regardless of applied gate voltages. In fact the whole CPU would just be one open circuit. Just a thought, I could be wrong.
While it is very impressive, this discovery, it is important to note that a great deal of work will need to be done to make this a viable material.
A cursory glance at the pre-publish pdf shows that, even when zero field cooled (brought below transition temperature in the absence of a magnetic field, the field applied after the material is already cold), the MgB2 pellets created by Nagamatsu et al are fairly susceptible to flux penetration. Make no mistake, MgB2 materials will be perfected, and may compete with NbTi in the future, but they are still quite a ways off.
If you take the time to take a look at figure 4 of the writeup though, you will clearly see that MgB2 is superconducting, but Niobium Titanium wires have proven useful up to ~45T (tesla), whereas, in a 10 Oe (oersted) field, MgB2 ZFC was succeptible to roughly 1.2T.
Still a damned fine piece of work.
The content says "While this is still much colder than some ceramic superconductors (which have superconducting temperatures of around -113 C or 160 K)". So what's the title? "High-Temp Superconducting".
I'd make a comment about lowered stock prices forcing the crew to buy much cheaper crack, but the mod-bots apparently grep for the phrase "stock price" and auto-decrement.
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(Hey Ryan! Here's your proof!)
The material in question is magnesium diboride or MgB2, which would almost have to be a borderline ceramic/intermetallic, which means it won't be much easier to process than a ceramic.
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The internet is the greatest source of biased information in the history of mankind.
While interesting in an academic sense, such a discovery is rather trivial in a practical sense. Superconductivity itself has a number of astonishing uses that can sometimes look like magic, but they're only useful when we can get them to occur at useful temperatures. Unfortunately, cooling something to 1K will require something along the lines of laser cooling in order to achieve, and this turns out to not be very practical. Superconductors with a very low critical temperature cannot conduct much current before they exceed their critical energy level and "go normal".
Useful superconductors are more in the line of HTC's, high temperature superconductors. The simplest of these are the superconductors that work when cooled to the order of 70 degrees Kelvin (-200C) by liquid nitrogen (which is cheaper than beer). If I recall correctly, the highest published HTC was around 175K, which is only 100 degrees below freezing. I've heard rumors of higher temperature superconductors, but haven't seen any referreed publications of results yet. Keep your eyes peeled, we'll see room-temperature superconductors within the lifetimes of most slashdotters.
To be fair to lower temperature superconductors, I believe the maglev train in Japan uses a lower temperature superconductor cooled by liquid helium, which is somewhere down on the order of 10K.
Superconductors aren't too useful for their property of not conducting current, since they have a critical maximum current level anyway. They are mostly used for their diamagnetic properties (they repel magnetic flux lines). This is the basis for how an MRI works, or for how super-fast magnetic trains work.
Whoa...you're WAY off. The "old theory" of superconductivity (the BCS theory, developed by Bardeen, Cooper, and Schreiffer) is still very much correct. NOTHING about this discovery implies that the theory is wrong, incomplete, or anything of the sort. What's remarkable is that noone expected to find a "conventional" (I'll explain below what I mean by "conventional") superconducting metal with a transition temperature much above the ~20K temperatures which have already been achieved in niobium alloys.
So anyway, on to what I mean by "conventional" superconductor. Electrons in metals interact with the underlying crystalline lattice; momentum is exchanged by causing the lattice to vibrate. Normally, two electrons will repel each other, since they both have negative electric charges. However, in a crystal, the lattice can mediate an effective ATTRACTIVE interaction between electrons (an electron-phonon-electron interaction, for those who like terminology). Thus the electrons can form bound pairs, which behave quite differently than lone electrons (they behave like "bosons"), and the system can enter the superconducting state (which is rather similar to the superfluid state in, e.g., liquid helium-4). Just what that state is would require a much longer explanation.
As a consequence of the fact that the electron pairing is due to the lattice, the transition temeperature (and other properties) of a conventional superconductor is influenced by the mass of the nuclei in the lattice. This phenomenon is known as the "isotope effect", and was a key piece of evidence which lead to the development of the BCS theory. I felt I had to correct the parent post precisely because of this fact. This recently discovered superconductor shows a variation of transition temperature with boron isotope mass which is just about exactly what the theory of the isotope effect predicts. This is STRONG evidence that this new MgB2 superconductor is a conventional superconductor, albeit one with an unexpectedly high transition temperature.
The "high-Tc" (ceramic, YBCO, etc.) superconductors seem to have a different pairing mechanism (i.e. not electron-phonon-electron, as in BCS), and thus require a different theoretical explanation. That doesn't mean BCS is wrong, just that the ~15 year-old ceramics are in a different class of materials.
The Washington Post has a nice article on it.
I thought that you had to do that now to keep the Pentium 4 from overheating?
Ok my karma is maxed out. When do I become Enlightened?
God I hope not. Remnants of that one X-Files episode where that poor unfortunate sap falls into the liquid nitrogen abound.
I can just see myself probing around in my computer case, accidentally hyper-freezing it and then smashing it to pieces against my desk.
- I don't care if they globalize against free speech. All my best free thoughts are done in my head.
I'm not nearly as impressed by the high-temperature ability of this conductor as I am by the fact that it can "beckon." That's gotta be pretty cool. I bet the technician who first noticed the behavior sh-t himself...
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It would do 550 with air + heat sink so i borrowed some liquid N2 from my physics lab, cut a coke can in half and strapped to cpu and poured in the Liquid nitrogen. CPu booted to windows at 700 mhz but then the power suppy exploded as i forgot to vent cold gasses out the case
Maglev trains wouldn't be so electric thristy, no loss long distance power cable, super efficient turbines and of course fast processors. Which do you think is going to be the most important apllication of super conducters?
I think that the most important applications are going to be the ones that are impractical to accomplish with conventional conductors (logically enough). All of the applications you mention would be _helped_ by superconductors, but are getting by adequately without them (wheels work fine on most trains, for instance).
One of the more interesting applications on the horizon is plasma manipulation. We already have many tools that use plasma as a working medium (etchers, torches), but there are a number of fun things you can build if you don't have to worry about resistance in your magnet coils and related circuits.
My personal favourite plasma application is a fabricator that uses patterned plasma deposition. This would work with a wide variety of materials, unlike normal fabricators. You need a plasma because otherwise it's difficult to confine and pattern your source materials. Superconductors would be useful because the most interesting fabricator design I can think of requires wobbling of a very strong magnetic field TV-scan-style, which would have horrible resistive losses if implemented with conventional components.
Fabrication by plasma deposition is much too expensive to be competitive for most things, but there are niche markets.
Fusion power is one of the more interesting plasma applications, though superconductors may not ever be up to the task. You can Brute Force a better fusion reactor by using a stronger magnetic field, but resistive heating of the magnet coils is only part of the problem. Outward pressure on the coils due to magnetic is one of the main engineering design limits to magnetic confinement reactors. There's also the problem of superconductors breaking down in strong magnetic fields, which renders them useless for high-field applications. High-temperature superconductors are especially bad for this.
In practice, problems with fusion are likely to be solved by clever design as opposed to brute force and ignorance solutions.
Thinking of more applications is left as an exercise to the reader; these are just my personal favourites.
I work for Physical Review Letters (and related journals at the American Physical Society) which is publishing the papers from the Ames, Iowa group. Interestingly enough, the first published paper (in the print journal today, available online since last week at http://link.aps.org/abstract/prl/v86/p1877) has set some new records in our office, in part thanks to increasingly all-electronic processing:
Manuscript received: 30 January 2001
sent to 2 referees: 31 January
Both referees report: 1 February
approved: 2 February
scheduled for an issue: 2 Feb
Updated manuscript received: 2 Feb
proofs available to author: 6 Feb
Author returned proofs (on the web): 8 Feb 2001
A final proof of the article available just over one week after being submitted, and going through a complete peer-review cycle!
More typically each step takes a week or two, though times have been generally improving lately.
But these new superconductors are pretty important!
Also interesting is that Nature has a nice "prepublication" look at the article on the original research, which they are publishing March 1 - Nature in the past has had an "embargo" policy preventing scientists from even talking to journalists about their work before the official publication date, but they've had this page up roughly since we published our related article online. The nature of scientific publishing is changing too here...
Energy: time to change the picture.
High-Temperature Superconductors: http://slashdot.org/article.pl?sid=01/02/23/191222