19 ms·
Ferromagnetic half levitation of LK-99-like synthetic samples
- sethammons 3y ago> We argue that, together with the pronounced shape anisotropy of the small fragments, the soft ferromagnetism is sufficient to explain the observed half levitation in strong vertical magnetic fields. Our measurements do not indicate the presence of the Meissner effect, nor zero resistance, in our samples, leading us to believe that our samples do not exhibit superconductivity.
- freeone3000 3y agoSo a completely different compound in a completely different shape.
- depereo 3y agoStill helpful. Now people know this synthesis process and result doesn't have this desired property and the 900 other groups working on this don't need to repeat it.
- xqcgrek2 3y agoThe XRDs are nearly identical. It's a dead horse.
- ycui1986 3y agoXRD used here only shows crystal lattice information for random orientated polycrystalline. It does not mean the two samples are identical. It does not prove whether they had single crystal or polycrystal. You will need a four-circle diffractometer to prove two samples are identical, that also only work on single crystal if anyone can make it.
- carabiner 3y agoXRD comparison isn't from eyeballing. The fact is, the original papers do not coherently specify "LK-99" because their equations, synth procedure, and subsequent analysis are all incomplete or contradictory. It's like they gave everyone 2 + 2 = 5 and so everyone's been trying to figure out how to get to 5, while also questioning 2 and 5 because the quality of the papers is so poor. "We do not know the composition or structure of #LK99 with any confidence." https://twitter.com/Robert_Palgrave/status/1687235756702752768 https://twitter.com/Robert_Palgrave/status/16872357567027527...
- XorNot 3y agoDifferent but reproducing the only real current "signature" LK99 behavior anyone's been able to show. That a definitely non-superconducting material can do something similar is bad news for LK99.
- GuB-42 3y agoYes, but I take it like a rebuttal. They got the same effect that got everyone excited (half levitation) with a similar material that is ferromagnetic. Considering that there is a lot of unknowns and randomness regarding the synthesis of LK-99, and that the half levitation effect can be explained by ferromagnetism, to me, it sounds much more likely that the original LK-99 is a ferromagnet rather than a superconductor. Simply because ferromagnets are common, and a room temperature superconductor is an extraordinary claim. I'd like to be wrong, but for now, it doesn't look good for superconductivity.
- throwawaymaths 3y agoThis is bad logic. Ferromagnetic explains half levitation but it doesn't explain full levitation. Superconductivity is sufficient to explain full levitation and half levitation. > Simply because ferromagnets are common Sure, metal ones are, but Are ceramic ferromagnets (without iron) common? That lone electron in an orbital is pretty important.
- Jweb_Guru 3y ago> Ferromagnetic explains half levitation but it doesn't explain full levitation No one reputable has actually demonstrated full levitation, including the original team. > Sure, metal ones are, but Are ceramic ferromagnets (without iron) common? That lone electron in an orbital is pretty important. They literally reproduced this behavior with a substance that looks identical to the original LK-99, so while it would be quite unusual, it is clearly possible. Apparently ferromagnetism without any ferromagnetic compounds has been witnessed before, e.g. in ZnO.
- throwawaymaths 3y agoNever claimed it was impossible, just that it's rare. > No one reputable I don't care about reputability of anyone unless they have a known past of fraud. Gatekeeping in science is lame unless someone makes a claim to break well understood theory or claims to do something technically difficult. RTSC is neither. Do you think this video is faked?: https://twitter.com/Andercot/status/1687740396691185664?s=20 https://twitter.com/Andercot/status/1687740396691185664?s=20
- hliyan 3y agoYes, but it allows for an Occam's Razor explanation of the observations so far.
- VHRanger 3y agoAfter reading the r/physics thread on LK-99 [1] I've cooled significantly on the matter. Basically: people who work in SC think the initial science seems very sloppy and the replication attempts don't come close to what you need to demonstrate a RT SC [1] https://www.reddit.com/r/Physics/comments/15i3h9d/lk99_megathread/jus73e6/ https://www.reddit.com/r/Physics/comments/15i3h9d/lk99_megat...
- carabiner 3y agoPeople were saying the initial papers were trash in the first day of their release over a week ago, so that's ancient history and immaterial now. Same with the "replications," they're obviously insufficient when they're generating pieces the size of a pin head that can't be attached to probes. All of us are in a holding pattern waiting for some big lab like Argonne to confirm or deny its SC status.
- VHRanger 3y agoHow would you *deny* the SC status? Replications keep failing until everyone is pretty sure it's not it. Proving the absence of something is rare to see.
- dralley 3y agoChecking the original samples, for one.
- jacquesm 3y agoI hope that ultimately it will come to that because I don't think anything else will put this to rest one way or the other (unless it is 100% confirmed/reproduced by another lab). It also seems to be the shortest path to a resolution.
- willis936 3y agoThat also adds little value. It would add no information on whether or not the sample is a fluke. We need to understand the material properties and its composition.
- arpowers 3y agoMy main concern: Where are the original authors and why are they not helping people synthesize the replications?
- jacquesm 3y agoThat's a good question and there is a lot of speculation about that but ultimately we just do not know. There is a whole tree that you can set up to track their reasons, the big branch at the beginning is labeled 'it doesn't work' (which obviously is a bit short on the confirming side, it may still have a 'fraud' and a 'true believers' branch but that's academic) and then from the other branch you get branches which may be labeled as 'they don't know how they did it' and so on.
- EthanHeilman 3y agoThey weren't ready to publish and then got forced into the lime light by a member of their team going rogue. We should give them some benefit of the doubt due to the circumstances, even if LK-99 turns out not to be a SC, they didn't choose to publish.
- jacquesm 3y agoOh I definitely do give them the benefit of the doubt. Regardless of what is going on as long as it eventually works as advertised it's all fine and as long as their samples don't go missing they have a way out that's pretty easy.
- jgtrosh 3y agoAccording to Wikipedia: > On 3 August 2023, the Korean LK-99 Verification Committee requested a high-quality sample from the original research team. However, the team responded that they would only provide the sample once the review process of their paper, potentially submitted to APL Materials, is completed. This process is expected to take several weeks or months.
- fbdab103 3y ago
- m3kw9 3y agoHas anyone even seen a ferromagnet stand up like that in a magnetic field?
- versteegen 3y agoYes. https://nitter.net/VanGennepD/status/1688052003216261120 https://nitter.net/VanGennepD/status/1688052003216261120 And this new paper finally rigorously explains away all the half-levitation videos. They can no longer be considered any evidence of SC at all.
- tamimio 3y agoLol, so it was all super glue and iron!?
- throwawaymaths 3y agoFor the half levitated ferromagnetic sample: isn't there torsional force where that disc touches the magnet? At this point we have many examples where it's fully levitated.
- delabay 3y agoall the full levitation videos are questionable in origin. I'd even go so far as to call every single one of them fake. No credible reproduction has featured a levitating sample.
- srslack 3y agohttps://arxiv.org/abs/2308.01516 https://arxiv.org/abs/2308.01516 https://nitter.net/altryne/status/1686279028523847680 https://nitter.net/altryne/status/1686279028523847680
- fnordpiglet 3y agoNot all the replication videos show the sample in the middle, see the Varda sample videos. Constructing something that simulates something else is proof of very little, other than there are other possible explanations. The existence of alternative explanations isn’t a proof the proposed explanation isn’t true. This paper doesn’t explain away anything yet - they’re conjecturing based on their experience with their sample. Their conjectures are no more credible than the opposing supporting conjectures. IANAP and I don’t have a horse in the race, and while I’m excited to see if this is true, I don’t believe anything other than there’s a long road of research ahead and nothing will be proven with hottake nitter videos or hottake preprints.
- jonathan_oberg 3y agoAh damn.
- JohnBooty 3y agoWhat happened to the original LK-99 samples that (allegedly) displayed SC properties? Were they just thrown in the dustbin, or what? I haven't seen that question answered or even asked anywhere, but I'm just a layman so maybe I'm not looking in the right places.
- Jweb_Guru 3y agoThey were refusing to share them with anyone reputable until today. Today, they said they would share them, so hopefully this will all be over soon (but IMO it's already resolved).
- canadiantim 3y agoResolved in which way?
- carabiner 3y agoLink to where they said that today?
- lifthrasiir 3y ago> They were refusing to share them with anyone reputable until today. This is incorrect (under some definition of "reputable"), because KENTECH [1] has reportedly received samples from Q-Center for the analysis, which started on July (following the MOU on May) and is estimated to finish within 6 months. Whether KENTECH is reputable or not, and whether it should be considered affiliated with Q-Center is of course debatable. [1] https://www.kentech.ac.kr/ https://www.kentech.ac.kr/
- ldjkfkdsjnv 3y agoI knew it was fake, there would have been a huge rise in the stock market. Financial markets would have sniffed this out. The market never lies. If anything, this was an obvious opportunity to short it on prediction markets.
- javajosh 3y agoIf fake those researchers careers are over. Like, they'll have to go into programming or something. And they've also besmirched the good name of Korea, and their moms are going to beat the shit out of them for fucking up that bad. They've got a LOT to lose if this is fake, which is why I think it's most likely true. But hey, sometimes people just do crazy shit.
- ldjkfkdsjnv 3y agoImpossible, wall street has some of the smartest scientists on the planet. They absolutely went through the research and determined it was a fake. Look at the AI boom, nasdaq rallied 40%. Superconductor would have had the same effect
- delabay 3y agoLike how the markets caught on to Covid in early February 2020? China shutting down, drowning in body bags, yet US markets don't flinch.
- ssa_form 3y agoYes but LK-99 is practically unusable in current form if it's a superconductor. There needs to be a lot more material science research before it can be put into utopian use cases that everyone is dreaming about. Recent AI boom brought a lot more finished products which can be immediately put to use.
- r0m4n0 3y agoYea all those geniuses missed COVID completely though. And then the market overreacted in every way possible causing a crash then a rally that compared to nothing we have seen. Not sure the stock market tells us much of anything
- scythe 3y agoA ferromagnetic oxide featuring copper as the sole transition metal would be very weird. I'm not aware of any examples of the copper block demonstrating ferromagnetism without a more "conventional" ferromagnetic transition metal (from Cr to Ni and cousins). But ferromagnetism has been demonstrated in black phosphorus: https://www.sciencedirect.com/science/article/pii/S0038109818303983 https://www.sciencedirect.com/science/article/pii/S003810981... So the most likely explanation for the observation here is that the sample contains black phosphorus. But do all the samples contain black phosphorus?
- 46Bit 3y ago(Not a scientist, just a hobbyist.) Red phosphorous is an ingredient in the original paper’s process. https://patents.google.com/patent/US6110438A/en https://patents.google.com/patent/US6110438A/en claims that black phosphorous can be made from red phosphorus using a vacuum and hundreds-of-C temperatures. Both of which people have done. Seems very possible.
- rcpt 3y agoDoes that PDF have a video embedded?
- segfaultbuserr 3y agoFun fact: You can even embed JavaScript-controlled 3D models inside PDFs https://helpx.adobe.com/acrobat/using/adding-3d-models-pdfs-acrobat.html https://helpx.adobe.com/acrobat/using/adding-3d-models-pdfs-...
- hliyan 3y agoAccording to this: https://twitter.com/Andercot/status/1688598313497694208 https://twitter.com/Andercot/status/1688598313497694208 "...there is a less well-known exception to this rule called Brauenbecker extension which provides a mathematical proof that levitation is possible with a simple diamagnetic in a dipole field so long as the diamagnetic material mass is very small relative to the strength of the magnetic field." I was very hopeful in the early days and was following the developments eagerly. Unfortunately, now I'm 99% convinced that LK99 is not a superconductor. Hopefully, what we learned from the saga and the momentum will help advanced the field a bit faster.
- NovaDudely 3y agoThe best we can hope for is that there is some sort of SC properties that can be investigated further even if this is not the holy grail moment many wanted it to be.
- ThePhysicist 3y agoMaybe a cautionary reminder to not listen to random influencers on Twitter. The expert community was really silent and reserved from the beginning as they've seen such wonder materials many times. Having worked in that field for many years I'm personally skeptical that there ever will be an ambient-pressure, room-temperature superconductor. The band structure and interactions that need to be present in the material are just one requirement for superconductivity, the other is that the ground state can actually form and won't be destroyed by thermal noise. However, the strong electron-phonon interaction required for (classical) superconductivity also makes the system susceptible to thermal noise, and in my opinion the thermal noise level at 290 K is just too much even for an ideal superconducting material.
- p-e-w 3y agoSo if good old ferromagnetism/diamagnetism is sufficient to explain the half-levitation shown in the video: How can I build my own half-levitating objects from standard materials? I've seen the science toys using pyrolytic carbon, but they are nowhere close to the effect from the video. Levitation height with pyrolytic carbon is like 1/20th of what the video demonstrates. The disc in the video looks like it's just about to take off. Can this be replicated with previously known materials at room temperature?
- throwawaymaths 3y agoI believe (could be wrong) diamagnetic levitation also requires arrangements of several magnets that shapes the magnetic field in a particular way
- XorNot 3y agoYes: https://twitter.com/VanGennepD/status/1688052003216261120 https://twitter.com/VanGennepD/status/1688052003216261120 This guy goes into detail how he makes a practical fake which demonstrates the same behaviour: it's ground up carbon, superglue and some iron filings on one end. The pivot point reduces the mass and weights it upright.
- marcosdumay 3y agoGo through iron milling residue (that kind that is dust-like at afar, but consist of large flakes) and select some thin and long piece. Put it over a glass, and move a magnet under it. You will see it position itself on a vertical or any angle you want. But notice that the videos circling the internet show a different behavior. Those are not homogeneous materials, and it's not easy at all to tell what they are actually doing. (But ferromagnetism on LK-99 is surprising by itself.)
- lamontcg 3y agoI thought LK-99 looked like bullshit from the start, but the conclusions of this preprint should really be confirmed and there's still a lot they don't understand about the behavior of the sample that should get more fully explained. And there might be something with this material showing semiconductor like behavior that could still prove more mundanely useful.
- versteegen 3y agoVery interesting comments on the paper by Prof. Michael S. Fuhrer https://nitter.net/i/status/1688755932275384320 https://nitter.net/i/status/1688755932275384320 > But I think they buried the lede a little. Ferromagnetism is novel and unexpected in this material system, and might be interesting. But strong diamagnetism even more so > Even if the diamagnetic fraction is the entire sample (appears less) then it would be the second-strongest diamagnet known (and pyrolytic graphite's diamagnetism is very anisotropic). In both Bi and graphite, diamagnetism results from unusual band topology. It's not common > Overall, some evidence that as-synthesized nominally Pb_10-xCu_x(PO4)O ("LK-99") is magnetically quite unusual, with different fractions showing soft ferromagnetism and strong diamagnetism
- ironborn123 3y agoThere are 2 things in favor of the Korean team - Hyun-Tak Kim is unlikely to ruin his career and legacy for something careless and frivolous. But stranger things have happened, so lets assign a 10% probability to give some benefit of doubt to the team. - The various DFT papers show interesting flat band structures. But DFT is an approximation and also they do not take into account electron electron correlations. So lets assign another 10% probability for this support. This crude estimate would give a 20% chance of RTSC. Rest has to be resolved by actual demonstrations, primarily from the Korean team themselves, and then from reputed Western researchers/labs.
- gfodor 3y agoIf your sample's resistivity goes down as it warms up, odds are you didn't make the same thing the Koreans did.
- rishav_sharan 3y agoNaive question, and I hope someone more knowledgeable than me can enlighten me here; Why are we even testing for superconductivity with levitation, instead of just checking for current loss/heat loss while conducting?
- adambb 3y agoThe samples are super small and not homogeneous, so its tough to get any kind of accurate reading with probes, is my understanding.
- CrimsonRain 3y agoGenerated samples are too small and powder-like to test for that without a lot of difficulties. Note: I'm not a physicist. Just my understanding from reading.
- clmay 3y agoThis question has been asked with near identical or very similar wording in almost every LK-99 submission I've seen over the last week or so... Is there something botnet-y happening? I find it hard to believe anyone reading similar threads could have missed the numerous answers to this and similarly-formed questions that have been offered lately.
- tkzed49 3y agoIt could be the sheer volume of discussion. I've seen a lot of these posts and this is the first time I've read this question.
- clmay 3y agoMaybe it's because I have been obsessively ensuring that I read every comment on every top thread... Some kind of selection bias could be at play...
- Firmwarrior 3y ago
- testqer54 3y ago[flagged]
- testqer54 3y ago[flagged]
- kewp 3y agoSomeone on YouTube mentioned that LK99 is ceramic ie not metal which nullifies many of its potential uses even if it does turn out to be superconducting
- lifthrasiir 3y agoSince someone blamed "Soviet fan fiction" in which I did take a part (oops) [1], let's make my opinions explicit. I'm very sure at the moment: - That the publish of two arXiv papers was accidental and the second paper was only published to claim the proper authorship, thus the exact publish date was never controllable. - That top-tier Chinese universities do use Bilibili to post early results. This makes very hard to dismiss all Bilibili videos, though probably most would be. - That you can produce something like the floating rock as seen in the original videos with a synthesis method similar to the paper states. - That the synthesis method has an extreme variability depending on parameters. No single reproduced LK-99 samples are same. - Thus, that Q-Center did make something according to this synthesis method as well, but that is probably different to other reproduced samples. I'm cautiously positive that: - That LK-99 is not a deliberate fraud. The most probable possibility at the moment is therefore an honest but misguided mistake. I still reserve a nonzero but not large probability (5%) that this is indeed novel to superconductivity. - That LK-99 indeed has some peculiar properties when synthesis parameters are controlled right. The large variability does suggest singularities in the middle and Q-Center might somehow have gotten the jackpot. - That at least some authors (notably Hyun-Tak Kim) are clearly distinguishing the superconductivity and superconductor [2]. In the other words, they are aware that LK-99 (supposedly) exhibits superconductivity but might not be considered as a superconductor. - That there is a Russian group of scientists that claim some relevant knowledge and feel uneasy about the apparent dismissal of it. This might be the most controversial point I like to make, and my relative confidence partly comes from private information (like, I have verified the credential of Iris privately) so you don't have to completely trust me on this. - That the research group has not settled on a single theoretical explanation. This is probably why all LK-99 papers were different from each other in theory, and also why Young-Wan Kwon became "disgruntled" as Hyun-Tak Kim might have been his substitute. - That the late professor Tong-Seek Chair is indeed a madman, regardless of the veracity of his theory. I have suspicions that: - That the paper is intentionally vague about the synthesis method. This method is notably different from what their international patent describes, and this is AFAIK typical in the material science. Probably the paper describes a low-yield and low-quality but easy method, and their trade secret is an efficient process. - That Russian scientists and possibly LK-99 folks do have some theory that describes LK-99 better. I had to slightly weaken this point in the previous article because the actual difference was very unclear to me and other proofreaders (we have discovered this during the rewrite to avoid apparent misreadings). I now suspect that there is no actual theoretical difference but different paradigms may have resulted in different blindspots. So the "acceptance" of theory without paradigm may be seen as the fake acceptance to them, possibly explaining their sentiments. - That China realized this possibility as well and wanted to maximize their leverage, explaining why China universities go crazy about this. - Therefore, under these assumptions, that Q-Center's apparently suspicious behavior can be fully explained. I believe all of them needed me no advanced physics knowledge to derive. Any questions about those points are welcomed. [1] See the original reply https://news.ycombinator.com/item?id=36996337 https://news.ycombinator.com/item?id=36996337 and the current version https://hackmd.io/@lifthrasiir/lk-99-prehistory https://hackmd.io/@lifthrasiir/lk-99-prehistory for the context. [2] https://hackmd.io/@sanxiyn/seize-interview https://hackmd.io/@sanxiyn/seize-interview
- bobby_the_whale 3y ago[dead]
- Forgotthepass8 3y agoWhy hasn't the west published anything on this?