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Hardware Science

The Search for Room-Temperature Superconductivity is Continuing (acm.org) 66

Communications of the ACM checks in on the quest for room-temperature superconductivity. "Time and time again, physicists have announced breakthroughs that were later found to be irreproducible, in error, or even fraudulent."

But "The issue is once again simmering..." In January 2024, a group of researchers from Europe and South America announced they had achieved a milestone in room-temperature ambient-pressure superconductivity. Using Scotch-taped cleaved pyrolytic graphite with surface wrinkles, which formed line defects, they observed a room-temperature superconducting state. Their paper, published in the journal Advanced Quantum Technologies, has gained considerable attention in the scientific world... Although many in the scientific community remain incredulous, if valid, this development could help solve a key piece of the puzzle: how defects and wrinkles in a material such as scotch-taped cleaved pyrolytic graphite (HOPG) affect electrical properties and behavior within superconductive systems...

"We haven't reached a point where there is a clear path to room temperature superconductivity because researchers are either overly enthusiastic or deceptive," said Elie Track, chief technology officer at HYPRES, Inc., an Elmsford, NY, company that develops and commercializes superconductor integrated circuits (ICs) and systems. "People fail to check measurements and others can't reproduce their results. There is a lot of carelessness and sloppy science surrounding the space because people are so eager to achieve success." The team conducting research into scotch-taped cleaved pyrolytic graphite believe their discovery could tilt the search for practically useful room-temperature superconductivity in a favorable direction. They reported they were able to achieve one-dimensional superconductivity in pyrolytic graphite at temperatures as great as 300 degrees Kelvin (26.85 degrees Celsius), and at ambient pressure. Vinokur and physicist Maria Cristina Diamantini described the development as the first "unambiguous experimental evidence" for a global room temperature zero-resistance state. If true, the team's research could illuminate a path to new superconducting materials....

Others remain skeptical, however. For example Alan Kadin [a technical consultant in the field and a former professor of electrical engineering at the University of Rochester] pointed out that one of the key researchers for the project, Yakov Kopelevich, has been working in the field for two decades and, so far, "The results are not reproducible in other labs...Until someone else independently reproduces these results, I think we can safely ignore them," he argued...

Yet as scientists continue to bang away at the superconducting challenge — including the possibility of using generative AI to explore materials and techniques — optimism is growing that a major breakthrough could occur.

This discussion has been archived. No new comments can be posted.

The Search for Room-Temperature Superconductivity is Continuing

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  • by 50000BTU_barbecue ( 588132 ) on Sunday October 27, 2024 @09:28PM (#64898767) Journal

    Try a different room

    • Try a different room

      Or a different planet. Room temperature superconductors would be easy on Pluto.

      • Try a different room

        Or a different planet. Room temperature superconductors would be easy on Pluto.

        Yup. Just saw the NOVA episode, "The Planets: Ice Worlds" and the average temperature on Pluto is -390F. Building a room there will be complicated though.

      • Actually that makes me wonder, since the temperature of deep space is about 2.7K .. iron meteorites/asteroids floating out there must be superconducting. If there say selenium and a small amount of light from stars, that's solar panels .. so there may be charged up superconducting meteors out there with levitating particles around it.

        • Actually that makes me wonder, since the temperature of deep space is about 2.7K .. iron meteorites/asteroids floating out there must be superconducting. If there say selenium and a small amount of light from stars, that's solar panels .. so there may be charged up superconducting meteors out there with levitating particles around it.

          Congrats! You just created science fiction's floating sky islands! The Beast Wars writers would be proud!

      • Pluto would have a different outside temperature than Earth, sure, but that nothing to do with the temperature of a supposed room on Pluto. Presumably, if such a room were built, it would somehow be heated so as to be comfortable for humans without life support suits.
  • by haxor.dk ( 463614 ) on Sunday October 27, 2024 @09:30PM (#64898771) Homepage

    >Using Scotch-taped cleaved pyrolytic graphite with surface wrinkles

    They used a chewed-up school pencil.

  • > "The results are not reproducible in other labs...Until someone else independently reproduces these results, I think we can safely ignore them," he argued

    That's just common sense and the most practical approach given the historical and current state of superconductor research.

    • No, that's a little white lie. It's common sense to not even waste your time to reproduce it, but that doesn't make it not reproducible. You can just try to reproduce it fail and put the result on Arxiv even if you can't find some journal for it, did I miss any failed reproductions? I don't think so.

      But I get it ... pigs don't fly, the sun will come up tomorrow and HOPG is likely not a high temperature granular superconductor ... but what if? He feels that last question is such a waste of time he wants to c

      • Currently we just don't have enough of an understanding of superconducting to simply write off anything that hasn't been tried before or isn't immediately and obviously stupid.

  • Superconductors would be great, but Copper does the job. I imagine there could be really great microchips if the formula could be cracked, but otherwise, ya copper has some losses, but it is manageable.
    • Copper does the job.

      The 3500 km HVDC line from Xinjiang to Anhui carries 12 GW of power and loses 1.5 GW to copper resistance.

      • Seems like the energy should be created closer to where it is consumed.
        • Seems like the energy should be created closer to where it is consumed.

          How do you move desert winds to a rice paddy?

          Or Xinjiang sunshine to where it gets dark two hours earlier?

        • Earth is inefficiently arranged. If we expanded the Earth by extracting the core and adding it to the crust, we could have a much larger planet with the same gravity. Beyond that, we would be doing the equivalent of mining everything so we would have all the resources. And while doing this, why not arrange things so that solar, wind, and tidal all work at maximum potential?

      • by e3m4n ( 947977 )

        I thought the golden goose of superconductors is repelling 100% of magnetic flux?? It was supposed to be the holy grail of magnetic levitation.

      • The 3500 km HVDC line from Xinjiang to Anhui carries 12 GW of power and loses 1.5 GW to copper resistance.

        That's a hell of a project. It's hard to find a nice summary online, but here's a start: https://www.hitachienergy.com/... [hitachienergy.com]

    • by tlhIngan ( 30335 ) <slashdot@worf.ERDOSnet minus math_god> on Sunday October 27, 2024 @11:23PM (#64898909)

      Superconductors would be great, but Copper does the job. I imagine there could be really great microchips if the formula could be cracked, but otherwise, ya copper has some losses, but it is manageable.

      Except where it doesn't.

      The quest for room temperature superconductors is really driving by the power industry. First, pushing power down long power lines does incur loss - and while it's generally very small - well under 10% (usually under 5%) from when its generated to when you get to use it, it's still a huge amount. Even 5% of a gigawatt-hour is still 50 megawatt-hours of loss. And it's lost as heat.

      But as a superconductor, it would have two benefits - first, that loss just goes away. Just magical. Second, your wires can suddenly carry a heck of a lot more current - once superconductivity kicks in, the ampacity of the wire jumps by orders of magnitude. So suddenly the wire goes from being able to carry megawatts of power to carrying gigawatts without changing a single thing. (The limiting factor is actually the electron flux is so high that there's not enough space for them because of the atomic nucleus)

      Now, for some runs, it's actually economical to do this - to use a high temperature superconductor to carry the power, envelop it with cooling so it remains superconducting and to keep it chilled is still far cheaper than running traditional copper or aluminum wires.

      • by ctilsie242 ( 4841247 ) on Monday October 28, 2024 @12:44AM (#64899009)

        Even someone like me who has wired a RV with solar would love superconducting wires. That way, I don't either have to choose between expensive, thick copper, or silver clad copper and 12 volts, or up the voltage to 24 or 48 volts which allows for skinnier wires, but can give you a wake-up zap if you are not careful. The voltage drop is definitely an issue. It would be nice to replace 00 gauge wire with 14 gauge wire, both creating a lightness of setup, and not having to run a volt or two higher to compensate for voltage drop.

        Overall, it would be a ton of energy savings, even at the level of single watts, compared to megawatts, and it means less heat to deal with.

        If used for motor windings, it might be able to allow for much smaller, more powerful motors, perhaps on the scale of what was mentioned in the Foundation series.

        • That way, I don't either have to choose between expensive, thick copper, or silver clad copper and 12 volts, or up the voltage to 24 or 48 volts which allows for skinnier wires, but can give you a wake-up zap if you are not careful.

          If you're doing an RV you have additional complications which make the higher voltage more desirable. A big one is partial shading. You may well wind up in a location where there is some of that through a lack of options. Another one is partial sun days. If you wire in series odds are much better that you will get the voltage up to where you can do some charging even when it's grey out. Some power is better than no power, which is what you're going to have on a day like that if wired in parallel. And anothe

          • I am doing them all in series for a total OCV just under 250W

            er, 250V of course.

            The total wattage without angling the panels should be about 1500W, though I have to keep them clean for that. I have some ideas on angling them cheaply (in one direction, which is plenty)

        • by HiThere ( 15173 )

          Most superconductors are rather brittle, though, unlike copper. Don't expect it to be a one-for-one replacement.

          The importance is for things that non-superconductors just can't do, like small AND strong electromagnets.

        • Yeah, no one said super conducting room temperature wires would be less weight than copper, or cheap. They may very well be heavier, more expensive and more difficult to deal with.
      • The quest for room temperature superconductors is really driving by the power industry.

        Yes but I remain a little sceptical that, even if we eventually find a room temperature superconductor, it will be practical for large scale energy transmission. First, it may not be a metal - liquid nitrogen temperature superconductors are ceramic and it is really hard to make a wire out of them.

        Then there is the problem that superconductors can undergo a very rapid phase transition to non-superconducting. This can happen either due to exceeding temperature or a field critical values. When this happens

      • by GoRK ( 10018 )

        You are very enthusiastic, but you have forgotten about critical current. The more current you put down a superconductor, the higher the magnetic flux. At a certain level, the magnetism will disrupt the material's ability to form cooper pairs. In most superconducting materials the critical current is quite low, which is why things like MRI magnets and ITER magnets have historically needed to be very very big. Only very recent advancements in state of the art superconductors like REBCO tapes are finally achi

      • "So suddenly the wire goes from being able to carry megawatts of power to carrying gigawatts without changing a single thing"

        Except, of course, for all the copper.
    • That depends of course what âoethe jobâ is. If the job is creating incredibly high field strength magnets for medical imaging, or fusion, no, copper doesnâ(TM)t do the job at all. Liquid nitrogen and REBCO do the job, but fusion could be brought a lot closer to break even if you didnâ(TM)t have to spend a bunch of the power cooling down your magnet.

    • by ceoyoyo ( 59147 )

      Hope you never need an MRI. Or any of the drugs and other chemicals developed or tested using NMR.

  • by Anonymous Coward
    Death, taxes, and no such thing as room-temperature ambient-pressure superconductivity.
    • Death, taxes, and no such thing as room-temperature ambient-pressure superconductivity.

      fusion energy too? It is 10 year away, right?

    • Is there a proper rationale that explains why that would be true, or is this "I keep hearing about this but it never happens" fatigue?

      • by ceoyoyo ( 59147 )

        Being spoiled? This is (allegedly) a tech site, and actual tech isn't a new chat app, it's hard stuff that nobody has ever done before. Back in the olden times you might not learn about some new tech until it was available at your local store, but we get to hear about most stuff right from the beginning. Sure most of it is not going to work out, that's the nature of research. You might have also only seen one or two really new technologies in your lifetime, whereas we get new toys constantly and we're bitch

  • by OrangeTide ( 124937 ) on Sunday October 27, 2024 @11:13PM (#64898893) Homepage Journal

    I'm looking for body temperature superconductors.

  • Room temperature or not, it's still a case of the higher the better. You get so much more working headroom that it's worth searching for anything at higher temperatures.

    • Room temperature or not, it's still a case of the higher the better.

      Yes, but there are important thresholds for cheaper coolants.

      Liquid nitrogen boils at 77K and is way cheaper than liquid helium.

      At 195K, you can use carbon dioxide.

      At 250K, you can use R134a Freon (the same stuff your fridge uses).

      Above 273K, you can use water.

      • Been thinking about this for a LONG time! From Wikipedia:

        LNG typically contains more than 90% methane. It also contains small amounts of ethane, propane, butane, some heavier alkanes, and nitrogen. The purification process can be designed to give almost 100% methane.

        Boiling point for pure CH4 is 161.5 C (258.7 F; 111.6 K) which a LNG liquefaction train is designed to achieve (why the other stuff needs to be removed).

        From Wikipedia list of High Temp Superconductors:

        For Hg-1201, Hg-1212 and Hg-1223, the values of Tc are 94, 128, and the record value at ambient pressure 134 K (139 C)

        No one has commercialized these mercury-con

        • The 3300 km HVDC line from Xinjiang to Anhui is the biggest in the world by both length and capacity.

          It dissipates 1.5 GW of heat over 3300 km, roughly 500 watts per meter.

          The wholesale price of electricity in China is 8 cents/kwh.

          So, the loss per meter costs 4 cents an hour, $1 per day, $350 per year, and $14,000 over the 40-year projected lifespan.

          If you can't build and run a cooling system for less than that per meter and still cover the cost of the superconductor, then it's not cost-effective.

          • Once the cost of investment is covered the cost of renewable electricity waste power to heat is a big fat zero in accounting terms. There is nameplate capacity and the capacity any project can deliver to the commodity market or a wholesale consumer like an aluminum refiner. The power grid does not get smarter to use solar, it gets dumber, delivering power during the day just to get rid of extra production. The end customer has to get smarter and take the power from the grid when it is near free and
      • by evanh ( 627108 )

        Why a "but"? Shouldn't that be "because". Or did you misread what I wrote?

      • I think most fridges these days are R-290, basically propane.

        But you are right, there are critical temperatures. Though carbon dioxide tends to freeze to a solid, not a gas, so harder to use than liquid nitrogen, oddly enough.

  • by DrLudicrous ( 607375 ) on Monday October 28, 2024 @12:54AM (#64899015) Homepage
    RTSC would mean no more helium. Not this bullshit "helium-free" stuff the manufacturers claim (still has helium, and annoying recondenser to keep it liquid). But true helium-free. If critical currents are high enough that is. And if that is true we are talking about new magnet designs and geometries that will vastly improve patient care and reduce costs (at least if the US ever straightens out its Rube Goldbergian reimbursement structure). And that's just MRI. Powerful electromagnets based on RTSC would be a game changer for all sorts of things. Radiotherapy with charged particles in an MRI. Railguns. Maglev transport. Cheaper particle accelerators. I'm tired AF right now and this is just off the top of my head. You get the idea. Needs to be room temp, needs to be ductile material, needs to be capable of carrying large currents while remaining SCing.
    • RTSC would mean no more helium.

      Not necessarily. We already have liquid nitrogen temperature superconductors and that did not remove the need for helium cooled magnets because it did not have a very high critical field and, as a ceramic, it is really hard to make a coil from it. What you want is room temperature superconductor that is metallic (or at least ductile so you can make wires) with a high critical field. Not just any room temperature superconductor will do.

      • by evanh ( 627108 )

        That's out of date. They are already winding wire (tape to be more precise) looking "high-temperature" superconductors these days. My guess is MRIs are going to get cheaper. It just takes a while for the legacy costs to be amortised first.

      • by ceoyoyo ( 59147 )

        They are about to. Making wires was a challenge, but it's been pretty much solved, and the first high temperature MR magnets are being built. REBCO has considerably higher critical field and current desnities than typical niobium tin or niobium titanium magnets we use today.

      • To be clear, I made all these points in my original post. Has to remain SCing at high field is a reference to the critical field.
  • At least not by itself, without an external field.
    Atoms wiggle at room temperature. This causes electrons to collide with them - this is resistance. In superconductors the crystal lattice structure in combination with the low temperatures, makes the atoms a lot less wiggly and makes it possible for the electrons to flow unobstructed between them.
    Now you see why a room temperature super conductor is highly improbable, I dare say - impossible.
    There has to be something that stabilizes the atoms the way t
    • by HiThere ( 15173 )

      IIUC, existing superconductors don't really match the existing models of superconductivity. So your argument is plausible rather than valid. And it's quite reasonable for people starting from slightly different plausible assumptions to come to a different conclusion.

    • by jbengt ( 874751 )

      Atoms wiggle at room temperature. This causes electrons to collide with them - this is resistance.

      Not exactly. If you can get the electrons to pair up properly, the pairs act as bosons rather than the individual fermions they otherwise are. This allows many pairs to occupy the same state, which allows superconduction. Still, the pairs can be disrupted at higher temperatures by vibrations of the atomic lattice, which makes it difficult to find room temperature superconductors.

    • This is not how superconducting (supposedly) works.
      Read up on Cooper Pairs.
      https://en.m.wikipedia.org/wik... [wikipedia.org]

  • "Magnetic field sorting of superconducting graphite particles with Tc>400K"
    https://arxiv.org/abs/2410.180... [arxiv.org]

    All this should be read with "claimed" caveats :

    Researchers in France assumed that the granular superconductivity in graphite exists in only a tiny minority of grains, so they sorted powdered graphite using the grains magnetic susceptibility and then formed an aggregate with the lowest susceptibility fraction ... claiming superconduction in relatively large aggregates, by resistance measurement tho

Experiments must be reproducible; they should all fail in the same way.

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