10 ms·
Some remarks on possible superconductivity of composition Pb9CuP6O25
- rsfern 3y agoCool study - they made a Pb thin film and compared its superconducting properties to the recent reports on LK-99 reproduction attempts They’re hypothesizing that people may be getting superconducting nanocrystals embedded in maybe amorphous material. I don’t know if it’s typical to do microscopy in superconductivity research, but it would be super interesting to see more microscopic detail on what people are getting
- anonymousiam 3y agoElectron microscopy might not work. The moving electrons in the SEM or STEM would create a magnetic field that is opposed by the material, and the opposing magnetic field would affect the electrons and probably destroy any possibility of imaging.
- 0cf8612b2e1e 3y agoHeat the sample to 200C?
- anonymousiam 3y agoThat might work. I actually thought of it, but didn't mention it.
- xorbax 3y agoWhat about AFM? I don't know know if the superconductor has enough phase difference to be picked up in tapping, but who knows Has anyone produced magnetic cantilevers?
- tedsanders 3y agoYes, quite a few companies sell them. https://en.m.wikipedia.org/wiki/Magnetic_force_microscope https://en.m.wikipedia.org/wiki/Magnetic_force_microscope
- andrewflnr 3y agoI get the idea of superconducting islands in a non-conducting matrix. What I don't understand is what thin lead films have to do with it, particularly if the superconducting island thing is well established already. What does the lead film experiment add?
- raducu 3y ago> superconducting islands in a non-conducting matrix. Can somebody who read the article and is knowledgeable in the subject please re-assure me this doesn't mean the material only forms minute super-conducting islands and that we can make wires out of this material in the future?
- adrian_b 3y agoThe material is very fragile, so even if it will be proven to be a superconductor wires are not a possible application. Nevertheless, there are many applications where it could be used as layers deposited on a rigid substrate, so something like a PCB (a small one, which does not bend) or an interconnection layer for semiconductor chips or superconducting devices like Josephson junctions may be possible.
- rsfern 3y agoit’s just a hypothesis, but they are saying that maybe the LK-99 samples people are making look like their figure 4 with tiny superconducting islands of lead That doesn’t mean we won’t be able to make wires and devices in the future. If it’s confirmed that we’re seeing real superconductivity (especially above room temperature) it’s going to drive a ton of research on finding actually good synthesis recipes to make continuous macroscopic chunks of the stuff, even if the current recipe isn’t particularly optimal
- adrian_b 3y agoLead has been used just because it is the cheapest superconductor and it is easily available everywhere. They have deposited very thin layers of lead on an insulating substrate, making the layers so thin that they became discontinuous. On such discontinuous layers they have measured a few properties and the resulting curves looked weird, somewhat similar to what has been measured on LK-99. This was published as a reply to the people who wonder why the measurements done on samples of LK-99 do not resemble those measured on bulk superconductors.
- yieldcrv 3y agoI’m getting tired of these, mostly because I don’t have the fundamental knowledge to follow or synthesize the significance is there a youtuber or tiktoker I can follow? even the nerdiest tiktokers know how to communicate effectively so that would be useful right now, far more succinctly than what I’ve seen so far edit: just searching LK99 on tiktok gets it done example https://www.tiktok.com/t/ZT8LhJccL/ https://www.tiktok.com/t/ZT8LhJccL/ nothing you couldnt get from a summary anywhere else and these incremental random papers arent easily evaluated or worth your time yet
- abnry 3y agoJust wait for more comments in these threads. Someone knowledgeable is bound to explain more.
- _delirium 3y agoThe Wikipedia article on LK-99 is not a bad starting point.
- yieldcrv 3y agoI’ve skimmed that as well, its more about the ensuing posts and papers that are equally obtuse and have no update on wikipedia and aren't front page news anywhere I can’t understand them enough to judge, but is the lack of immediate fanfare from digestible reputable sources an indictment, or am I early? I cant tell where to put energy
- spiderbyte 3y ago[dead]
- jacquesm 3y agoThey are no more obtuse than your average discussion between a couple of IT people. Welcome to how the rest of the world sees us.
- 3y ago
- tlb 3y agoThe resistivity measurements I've seen are 4 wires soldered onto a chunk of material several mm long. If superconducting crystals are growing inside a bulk material, they might be much smaller. Suppose I had a polycrystalline material with ~ 100 um long superconducting segments. How could I measure the resistance of individual crystals? It's worth finding small superconducting crystals, because you can probably find ways to make them larger.
- ChuckMcM 3y ago4 wire resistive measurements to cancel out the resistivity of the probes is a standard practice[1]. [1] https://www.ni.com/docs/en-US/bundle/ni-daqmx/page/measfunds/4wireres.html https://www.ni.com/docs/en-US/bundle/ni-daqmx/page/measfunds...
- sudosysgen 3y agoThe problem isn't the resistivity of the probes, it's that the probes may not be connected to the same crystal.
- tlb 3y agoI understand the 4 wire idea, but the two inner wires are still farther apart than an individual crystal might be. So a material composed of 100 um superconducting crystals in a resistive bulk medium would appear resistive to probes that are 1 mm apart.
- ChuckMcM 3y agoGot it. Building a 4 wire 100um square probe would be doable certainly but not off the shelf.
- jacquesm 3y agoWhere have you seen them soldered? That would be very strange.
- tlb 3y ago
- erulabs 3y agoCan someone with more knowledge talk a bit about the most immediate and practical uses of a room temperature semi conductor? From what I understand, non-chemical batteries (ie: current-trapped-forever-in-a-rock), hand held MRI machines, passively levitating trains, and dramatically simpler nuclear reactors are on the table. However, the articles I can grok don’t exactly give a hint as to how far A is from B - ie: does a room temp super conductor solve for 5% or 95% of these challenges? I’ve never been filled with regret for not going to college. I did extremely well for myself and my family by avoiding it, despite my desire and my love for learning. But reading this… I’m very jealous of you physicists!
- wolfram74 3y agoOf that particular list, I would say levitating trains are currently solved from a technical view point[0], and are awaiting economic viability. I know enough about fusion to say while having stronger magnetic fields make things easier, there's a lot of plasma physics that needs to be understood to do confinement. Furthermore the easy reactions all have neutron radiation to deal with so it is an open question if it will avoid all the same social problems fission has had piled on it. Hand held MRIs... that's a stretch, you can make better detectors with SCs, but even so, I suspect you'll want to wrap the area of interest in some apparatus. One you didn't mention and I had been somewhat dismissing until last week was energy storage, we have big existing ones already[1] and several of their drawbacks go away if their refrigeration demands drop to 0. [0]https://www.youtube.com/watch?v=4ZX9T0kWb4Y https://www.youtube.com/watch?v=4ZX9T0kWb4Y [1]
- midoridensha 3y ago>Of that particular list, I would say levitating trains are currently solved from a technical view point[0], and are awaiting economic viability. No, they're not. They're already economically viable: that's why Japan is building one between Tokyo and Nagoya right now, and it'll be in service later this decade. The current bullet trains are huge money-makers and have been for a long time; the Chuo shinkansen will be too.
- 3y ago
- Ayaan_4125 3y agoOk
- onetimeuse92304 3y agoI think the important part is that AFAIK the superconductivity only happens within the crystalline structure. If that's the case then we are looking at really limited application. The magic of superconductivity pretty much vanishes the moment it has to interface with any non-superconducting medium. If you want to create lets say a superconducting winding for a magnet, the point of superconductivity is you can push a huge current through the winding with no heating. But nanocrystals can't accomplish it because there will inevitably be spaces between crystals and these spaces will have resistance and will generate heat. Now, this does not mean there won't be some applications. Nanocrystals or not, they still can be used to levitate trains if we can perfect production of this exotic material. And, the most important, we may learn more about superconductivity that will allow us to find other superconductors that do not have this limitation.
- ISL 3y agoThe entire modern era depends on large single crystals, especially, but not limited to, silicon. For non-silicon applications, take a glance at some of Cree's products, for example.
- reportingsjr 3y agoHigh performance gas turbine blades (e.g. in the F-22 engine and apparently some electricity turbines) are single crystal now as well. It's definitely a huge challenge to do manufacture, but possible.
- baq 3y ago> And, the most important, we may learn more about superconductivity that will allow us to find other superconductors that do not have this limitation. completely agreed. getting this thing confirmed beyond doubt is not the end, it's a very promising beginning. dump a few billion dollars on it to develop theory, experiment in related substances, maybe there can be something made that's elastic? or maybe this thing can be grown in zero gravity, which (perhaps regrettably) makes Musk the Levi Strauss of the space fabrication era? etc.
- regularfry 3y ago
- Torkel 3y agoFirst steps of how LK99 could be used - embed superconducting nanocrystals into things. Given how insanely much metals we use for conductors I think it will be quite a while until this sees any kind of mass usage. But wow what an industrial investment boom we would be part of if LK99 actually works. I also think it is very interesting that this entire class of superconductors will, as far as I can tell, be illegal in the EU for most application due to RoHS: https://en.wikipedia.org/wiki/Restriction_of_Hazardous_Substances_Directive https://en.wikipedia.org/wiki/Restriction_of_Hazardous_Subst...
- f_devd 3y agoThe article seems to imply it's re-evaluated regularly (and additive rather than blanket ban although I'm not sure if that's relevant): > It requires periodic re-evaluations that facilitate gradual broadening of its requirements to cover additional electronic and electrical equipment, cables and spare parts