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The first room-temperature ambient-pressure superconductor?

arxiv.org

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Re: The first room-temperature ambient-pressure superconductor?

#521

Post by wbl »

jacquesm wrote: post #487
serf wrote: post #483

Earlier quoted context omitted.

>There are a lot of examples where something seems perpetually 20 years away. I'd advise tempering the transistor-based optimism with just a skosh of fusion energy skepticism. most of the common examples are in-the-works or exist in some form, they just don't satisfy the 'every-person' checkbox yet. AI? sure. Flying cars? sure. Robots? sure. Fusion is in the works, too. Tens of billions of dollars being thrown into t…

> Fusion energy production doesn't (really) have that equivalent. It does, actually. It's the miniaturization that's the hard part.

We miniaturized fusion 70 years ago and they named a bathing suit after it. Keeping it going is the hard part, and it was messy.

Re: The first room-temperature ambient-pressure superconductor?

#522

Post by jacquesm »

TaylorAlexander wrote: post #520
jacquesm wrote: post #509

Earlier quoted context omitted.

You could probably do that but it wouldn't be a whole lot better than the existing traces: it's not usually the resistance that limits the size of circuit traces but the mechanical requirements, such as your ability to connect to them and to space them apart so you don't get crosstalk due to capacitive or inductive coupling. If you could use it to make circuits, especially of a high level of integration then it might…

Sometimes the resistance of the trace matters. I’m designing a motor controller that needs to carry 100 amps and the resistance of the copper means that large planes are needed to carry the current without overheating. Beyond that I agree with everything you’re saying.

That's absolutely true, in power electronics there are applications where the current carrying capability of the traces really matters. Typically you'd either use a very wide trace or some other trick such as via'ing together multiple layers of traces or even to tin-plate the trace. In extreme cases I've seen traces reinforced with solid copper bars.

There is also extra thick copper clad board ('heavy copper PCBs').

Re: The first room-temperature ambient-pressure superconductor?

#523

Post by floxy »

jiggawatts wrote: post #502
floxy wrote: post #412

Earlier quoted context omitted.

This is the better video: https://sciencecast.org/casts/suc384jly50n

That looks like a chunk of pyrolytic carbon, which can also float above a magnet.

Yes, this is either a fraud or the real deal. Not an honest mistake or pushing the boundaries of data fitting (a la, phosphine on Venus, etc.).

Re: The first room-temperature ambient-pressure superconductor?

#524

Post by javajosh »

telltruth wrote: post #71

Could someone explain why is this world changing?

Other commenters have science fiction dust in their eyes, and speak of room temp superconductors in general. But this particular discovery is a brittle crystalline structure that cannot be extruded into wires, and does not have the high current capacity required for power transmission or rail-guns.

It's an important, exciting step but it's very far from world-changing at this stage. Or if it is in a limited way. The first transistors were clunky affairs, of limited usefulness, world changing for ship-to-shore communication in the military. But then people discovered how to make them with deposition instead of factories, and they got smaller and faster, and they really did change the world. We're in the "clunky transistor" period.

Re: The first room-temperature ambient-pressure superconductor?

#525

Post by andbberger »

nick__m wrote: post #506
mcv wrote: post #459

Earlier quoted context omitted.

CPUs that don't generate heat? That would be pretty awesome.

Superconductivity is not enough for a cpu that doesn't generate heat, you would need a cpu built of reversible logic gate. Thermodynamics requires that when you destroy a bit of information you generate at least 2.9×10−21 J. It's the Landauer's principle.

logically reversible cpus would in practice still dissipate heat to complete a computation in a reasonable amount of time.

Re: The first room-temperature ambient-pressure superconductor?

#526

Post by pnpnp »

hollerith wrote: post #508
kibwen wrote: post #504

Earlier quoted context omitted.

> if you can show that there's no way to do what you want to do with lead-free The bar is even lower than that. For example, bullets are still made of lead, not because it's necessary, but because it's cheap, and despite the fact that it contaminates the meat of the hunted animal with lead.

Tangentially, the US Army has completely stopped using lead in bullets. Their 5.56 NATO ammo has copper where the lead used to be (i.e., inside a brass jacket) which reduces performance because copper is only 2/3 as dense as lead.

To be fair, the US Army puts a looooot of ammo in the ground, which can have pretty severe consequences.

The consumer market still uses it, which is probably a tiny fraction of what the military uses in training.

Re: The first room-temperature ambient-pressure superconductor?

#527

Post by jjoonathan »

serf wrote: post #483
pohl wrote: post #458

Earlier quoted context omitted.

I was with you on the first part. If this proves room-temperature/ambient-pressure is possible at all, that is huge. Not so sure about the "won't be long until it's optimized," though. There are a lot of examples where something seems perpetually 20 years away. I'd advise tempering the transistor-based optimism with just a skosh of fusion energy skepticism.

>There are a lot of examples where something seems perpetually 20 years away. I'd advise tempering the transistor-based optimism with just a skosh of fusion energy skepticism. most of the common examples are in-the-works or exist in some form, they just don't satisfy the 'every-person' checkbox yet. AI? sure. Flying cars? sure. Robots? sure. Fusion is in the works, too. Tens of billions of dollars being thrown into t…

My favorite example is the hydrogen fuel cell. It was invented before the lead acid battery back in the 1800s. PEM gave it a boost around the Apollo era, but that wasn't enough to make it widespread either. Lead-Acid went through its whole 100+ year character arc and hydrogen fuel cells still haven't found product market fit. Sometimes that's how it is.

Re: The first room-temperature ambient-pressure superconductor?

#528

Post by BeetleB »

generalizations wrote: post #37
danbruc wrote: post #31

After skimming the paper, it reads like a legitimate paper even though I have zero expertise in the area. That it is in Word instead of LaTeX makes it feel a bit less legitimate to me and they could of course always have some error in there setup. The most notable thing to me was that this was done in a thin film where structural defects are supposedly responsible for strain in the material which in turn enables the…

How much is latex used for papers outside of computer science? Medical researchers I know generally used word for their papers.

My advisor was a physicist, and a Fellow of too many societies (IEEE, IoP, APS, etc).

He did not know LaTeX. Most of his papers probably were in LaTeX, as his students knew it. But I remember multiple papers he "authored" in Word, because that's what the student preferred.

I was in a top 10 school (in physics and engineering), and I can assert that the fraction of physics faculty who did not know TeX/LaTeX was at least a quarter, and could be as high as 50%.

All the major physics journals would accept Word submissions.

It's not at all unusual.

Re: The first room-temperature ambient-pressure superconductor?

#529

Post by mildchalupa »

TaylorAlexander wrote: post #494
andreiklochko wrote: post #389

Guys, even if everything in this paper is true, the material as it is might have limited applications. From what they show, the critical field and critical current seem very low. 2500 Oe is like 0.25 Tesla. Even REBCO at 77K is >1T. And 2500 Oe is not even at critical temperature but much lower. From skimming through the article I couldn't find the sample size of the current measurement to get the critical current de…

How powerful is the magnetic field in typical brushless motor? Even if it can’t be used for an MRI machine, it could do wonders for efficient (and/or compact) robotics and electric vehicles. I’m also very curious what kind of inductors you could make for switching power supplies using superconductors.

1.5-2 Tesla you hit the knee of the BH curve and you saturate the steel.

Re: The first room-temperature ambient-pressure superconductor?

#530

Post by deckar01 »

JumpCrisscross wrote: post #394
andreiklochko wrote: post #389

Guys, even if everything in this paper is true, the material as it is might have limited applications. From what they show, the critical field and critical current seem very low. 2500 Oe is like 0.25 Tesla. Even REBCO at 77K is >1T. And 2500 Oe is not even at critical temperature but much lower. From skimming through the article I couldn't find the sample size of the current measurement to get the critical current de…

> the material as it is might have limited applications Is LK-99 part of a larger (either known or emerging) class of materials? I'm not understanding what the lead and copper ions are doing to create internal stress, and why that leads to superconductivity.

Pb(2)-phosphate is a crystalline compound. They are creating a 2D film of it using vapor deposition, then doping it with copper ions. This is a standard process in semiconductor manufacturing. There are room temperature ambient pressure materials doped to create quantum wells in production right now. They are not super conductors, because the quantum wells are merely impurities that reduce the resistance of the material. I believe this paper is claiming a crystal so saturated with quantum wells that it conducts primarily through quantum wells with almost no resistance (and that all of the other physical properties of a superconductor arise from this).
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