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.

Comments

SOMEONE HELP

[Anonymous Coward]

All my base are belong to them.

Re:No no no, re-read the HOWTO

[pb]

I'd rather they read the Moderation Guidelines first.
---
pb Reply or e-mail; don't vaguely moderate.

Liquid Nitrogen is too cold.

[Malc]

Liquid nitrogen could be too cold for everyday use in homes. If it's not properly looked after, it can be dangerious as it is colder than them temperature that oxygen condenses at.

Re:Liquid Nitrogen is too cold.

[ErikZ]

Bah. People notice billowing clouds of super cold nitrogen. What they don't notice is slow evaporation, and that their oxygen is being displaced by this source of nitrogen. In a poorly ventilated area it doesn't take much before you start feeling sleepy. Doze off in this situation and you'll die from lack of oxygen.

The main reason I haven't been experimenting with LN2. I live in a basement, I'm lucky to get sunlight, let alone fresh air.

Later,
ErikZ

Re:this is just the opening for a new theory

[Oliver]

Thanks for the real insight guys. I got snippets here and there and buuum, there was the wrong sum. I really (yes, seriously) find it exciting to be knowing about 20x more about the topic compared to when I made my first post. Thanks again.

<self-justification>
At least my wrong post gave birth to usefull stuff.
</self-justification>

this is just the opening for a new theory

[Oliver]

The significant thing about this discovery is, that the superconducting temperature for metals acieved here (39K) is much higher than what was tought to be possible in conventional superconductivity theoriy. The old theory on how superconductivity works has basically been proven to be wrong.
So if further research evolves into a new theory, researchers will know what to look for in their search for metals with even higher superconducting temperatures.

BTW, it is important that this is about superconducting metals. Ceramics have higher temperatures, but are inflexible and very difficult to make something out of them, especially thin long wires.

Re:this is just the opening for a new theory

[Christopher Neufeld]

It is not true that the BCS theory of superconductivity has been proven wrong. It is a very good theory for certain types of materials. It accurately predicts things like the ultrasonic attenuation, the isotope effect, and others, and did garner the Nobel prize (recall that the Nobel committee is very conservative, and won't offer the prize unless the result can be confidently expected to hold up).

BCS theory does say that the maximum reasonable temperature for phonon-mediated coupling in a homogeneous medium is approximately 27 degrees. Above that temperature, the elastic response of the lattice would have to be so high that the lattice would make a phase change to a more stable state. As this new material appears to be superconducting above this temperature, it implies that its superconductivity arrives by a different mechanism than that described by the classical BCS theory. That was the same reasoning which made the original lanthanum-based high-Tc superconductors such big news the moment they were announced.

Re:this is just the opening for a new theory

[Anonymous Admin]

The biggest problem with use of the "new" ceramic superconductors in industry is not the expense of cooling them, it is the fact they only superconduct while their matrix is oxygen deficient. Exposure to earths atmosphere for only a few days renders them useless until they are resintered in a vaccuum furnace. Yes they can be sealed, but sealings get nicked or cut, then you have a place that stops conducting and your wire explodes from overcurrent. The use of a metal should solve this problem.

Re:this is just the opening for a new theory

[norton_I]

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.

Re:this is just the opening for a new theory

[MattEvans]

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.

Re:Cool... or rather, cold

[kramer]

Having spilled liquid Nitrogen on myself on at least one occasion, and watched someone spill it on themselves intentionally, I can tell you just spilling it on you won't do squat. Now submerging your hand in it -- that's a different matter, but in general unless we're talking about huge quantities the liquid nitrogen will just evaporate, no harm done.

Re:SuperCool?

[darkonc]

This is one of those cases where the moderation itself was possibly funnier than the bare post. (of course, if you work for Intel it might not seem quite as funny).

Intel -- just short of Intelligent.
--

Re:Ummmm....yeah

[Bill Barth]

When one section of the superconductor stops superconducting Ohmic heating kicks in. If the current densities/magnetic fields are low then catastrophic failure can be avoided. But when they are high (O(1-10) Tesla, say) the Ohmic heating is usually fast enough so that the resistence continues to rise, the wire melts, the coolant boils, the safety valves come off, and you have a room full of LN2 or LHe. They call this a "quench".

It can be quite exciting/expensive :).

Also See High Temperature Superconductors of 02/23

[J.Random Hacker]

Just different news sources. Must be a slow news day?

The other article is here

Re:Ummmm....yeah

[empty]

That is why Nature posted the article on their website before it had been reviewed or published-- it truly is an amazing and potentially revolutionary discovery.

Probably so. But Pons and Fleischman also had an amazing and potentially revolutionary discovery...but because they went public before being reviewed, they caused great embarassment to the scientific community and cold fusion research in particular. In fact, by jumping the gun, they effectively killed cold fusion research in the US (maybe a good thing...). This situation is--I think--worse, because it is a respected publication (not the authors) jumping the gun to get the word out. Probably everything will be OK, but there is a slight chance that the researchers screwed up (perhaps subtly), and by being published without sufficient review, could cause lots of harm to superconductivity research.

Researcher: Please could I have some more money to develop and improve high-Tc metallic superconductors?
Congressman: Hey, weren't we promised great results on that a year ago?! You guys are just trying to milk the taxpayers! No moolah for you!

Re:The publication process

[empty]

sent to 2 referees: 31 January
Both referees report: 1 February

So did the referees spend any time reviewing the paper, or did they just read the title, glance at the figures and think "This seems interesting..." and accept it for pub?

Re:Ummmm....yeah

[jovlinger]

ok, you seem to know about this sort of thing.

what happens when the temperature rises above superconductivity? Will we see a catastrophic failure?

The scenario I'm envisaging is that the computer is chugging along, pumping alot of juice through its superconducting wires. However, the cooling unit failed a while back and now the temperature is rising... all of a sudden the CPU is no longer superconducting, and start heating up from the resistance. Because there's so much juice going through them, they heat up A LOT, until the whole thing just melts.

Is that what would happen? or is there not that sort of phase change behavior?

This story appears to have disappeared

[kahuna720]

from the main page. Strange.

A superconductor of this nature would be highly beneficial to scientists working in this field, however...surely the applications are numerous. Hopefully the ramifications of what this could mean are being tempered with the necessity of further study before any sort of deployment on a large scale occurs, for to implement such a solution prematurely could have potentially disastrous results.

Re:This story appears to have disappeared

[po_boy]

seems to have disappeared even from the "older stuff" area. weird.

All your event are belong to us.

Re:why is this moded up to 2

[dondelelcaro]

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

Are they actualy using superconducting magnets in medical NMR's? I don't seem to remember seing a dewer present in the last ones I looked at. They definetly don't need that much resolving power, probably only weigh in at like 100 MHz if that, and I thought you could reach that fairly easily with a non-superconducting electromagnet or permanent magnet. (I'm still picking up my NMR skills, work on a 500 MHz Verian doing duterium work... Oxford magnet, LiHE cooled, pretty normal stuff.)

is used to more easily create a high magnetic field to flip the spins of protons in your body.

The magnet orients the spins of the protons in the same direction. You apply RF to flip protons, and then recieve RF as they relax.

Course, your other points seem to be right on. (Not that I know much about superconductive materials...)

Don Armstrong -".naidnE elttiL etah I"

Industrial rev now what?

[Courier]

I guess you can say with the industrial rev we got running water taps in everyone's house ....

Maybe in 5 year's time we'll be seeing new houses with liquid gas taps.. and i though washing my hands in the winter sucks..

Re:Cool... or rather, cold

[Wiggin]

i can see the tech support calls now...

Re:Potentially Dangerous

[Ronin X]

Metallic super-conductors in particular can be used to create very lethal devices.

VERY lethal? Ah I see. A good point. If I am only SLIGHTLY killed by a terrorist with a SOMEWHAT lethal device, I'd feel much better than if I were THOROUGHLY killed.

Re:Superconducting metals are the first step.

[Ronin X]

The singularity will come, and it will come soon. By uploading my mind I will avoid negative consquences. I welcome this discovery.

Dude, you must have been on sabbatical or something, because all your buddies at Heaven's Gate already hitched a ride on the mothership.

ya gotta lick it.

[brad3378]

&gtHey, I triple dog dare you to lick it

I can't believe he skipped the double dog dare,
and went straight for the Triple dog dare!
That's unheard of!

Re:Cool... or rather, cold

[MaxGrant]

I did that in 9th grade -- stuck my hand under the stream of nitrogen as it was poured onto the floor -- without knowing what it would do, of course. Boy was that stupid. It turned out to be harmless (in fact, I'm quite sure the nitrogen never actually touched me) but it was one of those things I looked back on and said to myself, "Self, don't ever be so irretrievably stupid again."

Re:I don't mean to gratify a deliberate troll

[Dyolf Knip]

Well, you gotta admit, to anyone not knowledgable about this sort of thing, "flux penetration" sounds like a "Back to the Future" porno. But hey, thanks for the nifty info about superconductors.

--

Re:Ummmm....yeah

[SquadBoy]

The key word there is metal this would be higher than they have been able to do it with METAL in the past. Yup it's easy to insult people when you ignore words.

Close to the Temp of Liquid Nitrogen

[searleb]

Nitrogen (liquid), a common and relatively cheap method for cooling all sorts of things, has a boiling temperature of approximately -196C. Scientists only have about 40 degrees to go before they can start utilizing super conductors for practical applications.

Re:Cool... or rather, cold

[Bingo Foo]

Jearl Walker (physics education guru) used to do this trick too. He'd put a drop of liquid nitrogen on his tongue and blow a plume of vapor that a dragon would be proud of. One time he blew the drop off his tongue into one of his teeth and the sudden temperature change shattered the enamel. He doesn't do that trick anymore.

Bingo Foo

---

Re:Yesterday's news

[Treker]

You'd be surprised what some of the conspiracy theorists have been plotting--there's a whole controversy about the moon landing being falsified. This is old news, but very interesting.

I'm still not convinced that men did _not_ land on the moon...

liquid nitrogen

[the Atomic Rabbit]

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.

Liquid nitrogen boils at 77K, which is already below the critical temperatures of existing high temperature superconductors. You don't really need to improve HTSC technology any further to use liquid nitrogen.

Re:Interesting.

[wardomon]

That was a Larry Niven, wasn't it?

Re:SuperCool?

[GrandCow]

SuperCool? (Score:3, Informative)

I thought that you had to do that now to keep the Pentium 4 from overheating?

How did this POSSIBLY get an informative moderation? I can see funny maybe, even though the whole joke is getting rather stagnant... but informative?

What are you moderators smoking tonight???

-C

I don't mean to gratify a deliberate troll

[chaboud]

but "flux penetration" is very much a real term.

This is a very important concept in superconducters. As the flux (magnetic field) penetration increases, the resistance of the superconducter increases in a roughly ohmic nature. Superconductors "pin" flux in vortices in order to prevent this resistance, which leads to dissapitave loss. For movies of this go here, and for images of the Z component of flux in High Tc superconductors, go where I worked before I entered the private sector.

Please, do your research, I've actually done mine.

Not so hot this time

[OlympicSponsor]

Pretty good one. Although the impact is a LOT less when you do what I do with suspected trolls: Read the first line, then the last paragraph. You went from super-conductors to "terrorists irradiating our cities". Too much too fast. You should have stopped with "needs to be kept hidden".
--
Non-meta-modded "Overrated" mods are killing Slashdot

material that converts heat to electricy

[user flynn]

If someone researches material that converts heat directly into electron flow (current) than we will have the key. This material would of course absorb heat as it would be turning the kinetic energy of the nucleus into kinetic energy of the electron (wow- thats a lot of energy to be tapped!).

Re:material that converts heat to electricy

[merlin_jim]

Materials exist that do this. The problem is that it's not the energy you convert, it's the energy potential, as in potential difference.

Top-down in efficiency:

Peltier junctions, an existing technology, are produced by junctions of two metals. When electricity is applied, heat energy flows from one metal to the other. If the current is reversed, heat energy flows the other direction. If heat energy flows from one metal to the other, then a potential voltage is produced. However, in all cases, the Peltier junction, if viewed as an enclosed system with two inputs, increases in temperature and decreases in potential energy.

The second idea is that you harness the kinetic energy of the nucleus itself to create electric energy. This happens in ALL materials, and is why cold materials glow in the infrared. Warmer materials glow in the visible wavelengths (red-hot poker, etc.) The problem here is, to get usable energy out of this system, you have to be at a lower energy point. Meaning you have to be colder than whatever is providing you energy. This provides a theoretical limit on any kind of heat engine. It is against this limit that the efficiency of a heat engine is measured; even if you get a 100% heat engine, that doesn't mean that ALL the heat energy in it is being converted to another type of energy, only that it is at the theoretical limit for efficiency.

And last but not least, zero-flux vacuum energy. I won't go into the details, go here if you want them. The short of it is, virtual particles exist everywhere and there should be ways to tap them. It is often said in this field that there's enough energy in a cup of coffee to boil all the oceans of the world. And there is a way to tap it:

Take two large metal plates in relatively empty space. Infinite plates are ideal, but that's not going to happen any time soon. The important part is that they are reflective and lightweight. Place them close together, parallel, so that the space between them is a resonating cavity for EM radiation. If the empty space is empty enough (i.e. no light energy, etc.), then they will be repelled from each other slightly. This is because the virtual particles forming between them cause light pressure on the reflective surfaces, pushing them apart.

I've heard that this has actually been tried and proven to work, but don't have any concrete documentation. Anyone know any more details?

Anyways, the point is that, with this method, you STILL need a lower-energy point. By setting up the resonating cavity between the two plates, you've basically created a region where zero-point energy is higher than in the area outside the plates.

But don't let me be a complete downer. The energy holding an atom together was untappable at one point for the exact same reasons. Through a combination of superconducting technology for fast efficient energy exchange, nanotechnology for creating quantum cavities, and some as yet undiscovered technology, this could be the way we finally realize the dream of Athena (goddess of the technology of war); to become gods ourselves.

Re:Yesterday's news

[airship]

Of course the moon landings were falsified. They were filmed in a studio at the secret Nazi moonbase that has been in Copernicus crater since 1939.

So what happens if...

[jfdawes]

You replace the CuO2 in most conventional superconductors with MgB2?

Physics majors wanted!

[Dancin_Santa]

Can someone explain why the chip cooled by the OC in the previous post stops functioning at a low temperature? The overclockers mention something about a lack of 'free electrons'.

Is their theory correct? How do superconductors manage to avoid this problem when supercooled?

I carry a 24-hour constant-use tank of liquid nitrogen to keep the sleigh cooled, if you were wondering.

Dancin Santa

Re:Physics majors wanted!

[Macadamizer]

You're looking at two different things here. First, the supercooled chip stopped working at low temps due to a lack of free electrons. Semiconductors are insulators at very low temperatures, and their conductivity rises with increasing temperature, because the extra energy (from the heat) enables electrons to move from a bound state into a free state (jump from the valence band to the conduction band). Go to a low enough temp, the free electron become bound drop back into the valence band), no conductivity, the transistors stop working.

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.

Re:foist

[merlin_jim]

There's SO much wrong with this post. Let me cover the simple stuff:

• Superconductors do not "draw more electricity to achieve greater power"... any wire does that. All conductors use all the available electricity to do their work. Superconductors do not resist the flow of electricity at all, leading to 100% efficient energy transfer.
• Heat is not generated by current, it's generated by resisting current. Conductors convert a portion of the current flowing through them into heat; that's where the inefficiency lies. 100% efficient = 0 heat.
• I don't have the figures, but assume a .1% efficiency loss (that's gold wire folks, one of the best conductors known to man) and a per-capita usage of 500 Watts/hour... which is just about enough to run your computer, the fridge, and the lights at the same time. That's .5 W/hour being turned into heat... or 1800 Joules of heat per hour... or 7533 calories of heat per hour... enough to heat a liter of water seven-and-a-half degrees. It's probably a LOT more for first-worlders and a LOT less for third-worlders, but you get the idea. That's a lot of waste heat that superconducting technology can help us get rid of.

Uhhh..

[cavemanf16]

But watch out for spillage. That liquid nitrogen really smarts!

Re:Cool... or rather, cold

[foxwitt]

Just make your case out of austenitic steel and it won't shatter with liquid nitrogen in it (austenitic doesn't get brittle at low T). Also, that liquid nitrogen is some nasty stuff, froze part of my hand once when filling a jug with it. Very painful, very large blisters, ick.

Superconducting CPU

[HRB]

One is for shure: classical transistor based CPUs need semiconductors not superconductors. If you cool down a CPU to lets say 200K you would get an insulator rather than a semiconductor.

But I see an other (home) application: Maybe one can build superconducting magnets for the speakers of my stereo...

:)

Re:Superconducting CPU

[jd]

Nope. Sorry to disappoint, but you're correct.

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.

Re:Superconducting CPU

[Christopher Thomas]

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).

Re:Superconducting CPU

[WolfWithoutAClause]

True, superconductors do not semiconduct.

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!

Re:My favourite: Industrial plasma applications.

[Yazeran]

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.

This fenomenon is only found in the 'Type II' superconductors, but all the HighT ones belongs to this category (as far as i recall).

Re:Cool... or rather, cold

[ellboy]

Actually, I've fully immersed my hand in liquid nitrogen several times. One of my chem profs loved to play around with the stuff and let us all try dipping our hands in it if we wanted to. It was really creapy, actually took a bit of nerving myself up to do it. The strange part is, you can't feel anything except what I would describe as a cool fog. The reason this works is that your hand is so much hotter than the liquid N2, it just bounces off your skin like a drop of spit on a hot griddle. What you absolutely don't want to do is get your clothes wet with the stuff. The wet material holds the liquid against your skin and you'll get burns in seconds.

Re:Stupid Karma-Horing Post

[Account Number Three]

8/9. Your forgot to include the Rankine scale, where 0 is absolute zero and the measurement interval is equal to the degree Farenheit.

All your karma are belong to us!

I trust technology with a lot but...

[JiffyPop]

I think I would wait for the bug fixes just in case at the singularity the computers start designing their *predecessors* instead. I don't want to live out my existance as a PDP-11 or even a vacuum tube machine...

Potentially Dangerous

[qpt]

Easily and cheaply manufactured super-conductors are the mad scientist's wet dream.

Although often not considered in open source circles, technology has the potential to be incredibly dangerous and should not always be freely shared. Metallic super-conductors in particular can be used to create very lethal devices.

Liquid nitrogen and other cooling methods are already so cheap, that with the advent of these metallic super-conductors, mobile nuetron pulse devices become a real possibility. Ceramics always lacked the strength to fabricate a large enough super-conducting matrix, but this is no longer a problem when using metals.

The open source community often does not consider this, but some information needs to be kept hidden, and this is an excellent example of such information. We do not need terrorists irradiating our cities and children with devices that can fit in the back of a moving truck. Not all information wants to be free. We simply cannot afford it.

- qpt

750 GHz CPU's

[Darth Cider]

Don't forget your mention of Josephson Junction CPU's using supercooled niobium. http://www.spectrum.ieee.org/publicfeature/dec00/s up.html Could be that this new stuff can be lithographed rather than vapor deposited. I live in North Dakota. Any given winter's day, my fillings go superconductive. I can browse slashdot from my molars.

Why Scientists are happy about this:

[SirJimbo]

This new compound isn't the highest temperature superconductor right now. I believe that distinction goes to some sort of ceramic compound, whose temp is about 191 K. So what's special about this? Most high-temp superconductors are ceramics, not metals. Ceramic superconductors, known as type II superconductors, are very brittle (as anyone that has dropped a coffee mug will assure you). They also cannot be made into wires very well, which makes it harder to find an application for them. If superconductors were to be used in computers, the would have to be metallic, like this new compound discovered, to have any hope of forming the complex circutry involved.

Don't get your hopes up too quickly, though. Cooling with liquid nitrogen would probably damage internal components, unless the case was really well designed. Who ever thought that a Pentium could run to cold?

Re:Ummmm....yeah

[Bill Currie]

While I'm guessing, I imagine that there wouldn't be a major problem because the supplied voltage would be the same no matter what temperature, and thus as the resistance increases, the current would drop. Also, I can see the circuits being designed such that if super-conductivity is lost, they effectively switch off, in which case everything just comes to a stop until you refresh your coolant.

Bill - aka taniwha
--

Re:Not exactly

[Bill Currie]

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.

Ahhh, I thought I might be missing something, though the amount of voltage will depend highly on the rate of change. Still, there's two things I can think of that would help: careful design to re-route such voltages and currents (just like a diode across a solenoid) and even with superconductive circuitry, I don't imagine you would really want high currents in a CPU.

As to those superconduction toroids, yeah, coolant failure could be, um, interesting.

Bill - aka taniwha
--

How would a superconducting chip work?

[rve]

I can't quite picture a superconducting semiconductor in my head. Would such a chip just have superconducting interconnections? How does it work?

Re:How would a superconducting chip work?

[Christopher Thomas]

I can't quite picture a superconducting semiconductor in my head. Would such a chip just have superconducting interconnections? How does it work?

There are several ways of using superconductors to build integrated circuits. Using superconducting interconnects would reduce RC time constant delays, but not by a vast amount (the transistors provide most of the resistance).

The most promising approaches use devices other than transistors to perform switching. My favourite method was described in IEEE Spectrum a while back (kuro5hin article here: http://www.kuro5hin.org/?op=displaystory&sid=2000/ 12/10/0925/1544 )

Re:My favourite: Industrial plasma applications.

[Christopher Thomas]

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.

Re:The publication process

[apsmith]

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.

Pouring LN2 on your machine before startup? Done!

[ottffssent]

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:)

Well...

[dimator]

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...


--

Some thoughts

[cluge]

If they eventually find something that super conduct at resonable temperatures just thin of the applications. 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? Thats right, you guessed it. Slashdot fodder. I can just see it now...

"My ic2 liquied H2 chip can quick your wimpiums P10-ICE's ass" -joy-

room temperature vs. reachable temperature

[StandardDeviant]

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.

--
News for geeks in Austin: www.geekaustin.org

Re:Ummmm....yeah

[StandardDeviant]

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).

--
News for geeks in Austin: www.geekaustin.org

Not exactly

[mangu]

...thus as the resistance increases, the current would drop...

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.

Re:Superconducting metals are the first step.

[istartedi]

#universal_mind caused a segfault at 0x654gfde55487d8ec
brain dumped
#rm brain
#universal_mind -load next_victim.brain
#universal_mind caused a...

Re:Superconducting metals are the first step.

[joto]

By living in the first wave of the oncoming singularity, as predicted by Vernor Vinge, I hope to avoid its bad effects (the singularity is a moment of infinitely fast technological progress that occurs when computers become intelligent and design their own replacements).

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!

The Many Uses of HTS's

[d.valued]

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)

Re:why is this moded up to 2

[deglr6328]

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.

Stupid Karma-Horing Post

[mlong]

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

Re:Cool... or rather, cold

[caffeinated_bunsen]

#include <stddisclaimer.h>

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.

Superconducting CPU

[CapnEric]

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.

There is something important to take note of.

[chaboud]

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.

Ummmm....yeah

[OlympicSponsor]

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.
--
Non-meta-modded "Overrated" mods are killing Slashdot

Re:Ummmm....yeah

[norton_I]

The important thing here is that they have a metal that superconducts at ~40K. That is much higher than any other metalic superconductor (typical Tc ~ 4-10K). Metals are very easy to draw and make into wires, ceramics are not.

Also, the first ceramic high Tc superconductors were found at 40K and were quickly tuned to reach higher temperatures.

Also, MgB2 is non-toxic and available in mass quantities cheaply. If it can be made to superconduct at 77K (liquid nitrogen temperatures) with an appreciable current density, it truly would be a revolutionary advancment for superconducting applications.

That is why Nature posted the article on their website before it had been reviewed or published-- it truly is an amazing and potentially revolutionary discovery.

Re:another article on discovery

[dhovis]

Nice article, except that they refer to the material as "magnesium dibromide" which would be MgBr2, a common salt, not a metal.

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.
--

Superconductors for Dummies

[Eoli]

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.

another article on discovery

[jeffsenter]

The Washington Post has a nice article on it.

SuperCool?

[Ronin X]

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.

I thought that you had to do that now to keep the Pentium 4 from overheating?

Cool... or rather, cold

[Fervent]

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.

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.

Well, for me...

[MWoody]

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...
---

Liquid Nitrogen + celeron 366

[-douggy]

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

My favourite: Industrial plasma applications.

[Christopher Thomas]

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.

The publication process

[apsmith]

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...

Redudant

[milkman1]

This was on slashdot on friday, it refers to the same super conducting compound

High-Temperature Superconductors: http://slashdot.org/article.pl?sid=01/02/23/191222