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A sister paper [0] has a photo of the material exhibiting the Meisner effect and levitating over a magnet, and claims to have a video too. Either they blatantl
by eig 3y ago
A sister paper [0] has a photo of the material exhibiting the Meisner effect and levitating over a magnet, and claims to have a video too.
Either they blatantly photoshopped the photo or they actually made a room temperature super conductor. I can’t see how the could have made a subtle mistake that resulted in magnetic levitation at room temp without making a superconductor.
[0] - https://arxiv.org/abs/2307.12037 https://arxiv.org/abs/2307.12037
- swagmoney1606 3y agoVideo: https://www.youtube.com/watch?v=EtVjGWpbE7k https://www.youtube.com/watch?v=EtVjGWpbE7k I really need someone to bring me down a notch. This is too exciting!
- jacquesm 3y agoIndeed, this will change pretty much everything if true. A true room temperature / ambient pressure superconductor will cause a revolution in so many fields that I find it hard to believe. But if... Let's wait for replication before throwing a party. This is on par with the discovery of the transistor and possibly bigger.
- colechristensen 3y agoSuperconductors have a current limit above which they are no longer superconductors. It is possible that a room temperature superconductor could be created that has a limit too low to be of any practical use. It seems this is worth cautious excitement, but don't get too excited yet.
- prewett 3y agoThe abstract says that T_c is 127 C, which should be comfortably above room temperature for most of the planet
- tux3 3y agoCouldn't we make really thick wires to increase the current limit :) ? After all, there's no need for expensive cooling and the material looks reasonably cheap! (assuming it's real, of course..)
- jacquesm 3y agoLet's wait to see what the maximum number of A/cm^2 is before determining if that is even necessary. It's possible that they already normalized the figure, and if that's the case then 125 mA/cm^2 would be 'bad news' in the sense that even though the temperature and pressure are much better than other superconductors the critical current is much, much worse. But given the way the paper is formulated I'm not sure if that is a proper reading and it is very well possible that they are talking about a particular thin film sample (which would make it a small fraction of a square centimeter in cross section) and how much current they passed through that sample. In which case the situation would be much better already, especially if it turns out that the sample was extremely thin and/or narrow. Too early to tell without more information.
- jychang 3y ago250mA at 25 Celsius, according to the paper
- jacquesm 3y agoThat needs another element, the cross section of the conductor otherwise it is meaningless.
- colechristensen 3y agoOof, all right then. Perhaps there's room for improvement, but there would need to be a lot before this is useful/competitive even in lab settings. For comparison, high temperature superconductors (in this context high temperature means tens of degrees kelvin) like the recently rather revolutionary ReBCO has critical current values measured in hundreds of thousands of amps per square centimeter. That would be a factor of a million.
- jacquesm 3y agoIt's a thin film according to the article linked, but there is no mention of how thin it is (it could be a monolayer) and there is no mention of how wide the film was so the 250 mA figure can not be used to determine whether or not there is 'room for improvement' or even a necessity for that (unless it was already normalized, for which I see no evidence). The 'Critical current' isn't mentioned at all in terms of the cross section of the conductor, just as a function of temperature and magnetic flux which they really should have provided to be able to make sense of the figure. ReBCO is 8 MA / cm^2 (that's million, not milli), the thin film layer they tested with could well be so thin that it is in the same ballpark or it could be a small fraction. This is clearly a very early result and until they have more insight into how it works (assuming it really works...) we'll have to be patient before we get more meaningful figures on the actual current carrying capacity of thicker conductors made out of this stuff. They were happy enough to be able to prove superconductivity at room temperature and normal pressure, clearly they are still a ways away from being able to line up a comparison with ReBCO with respect to current density. But surely that will happen soon if this is real.
- megaman821 3y agoWhat material and setup could even fake that result?
- RivieraKid 3y agoAnd why fake it in the first place? I don't see the benefit.
- Koiwai 3y agoIt's a bit hard to break it to you, but Santa isn't real.
- RivieraKid 3y agoWhat's your point?
- Koiwai 3y agoAre you living in the fairy land? in the real world, Academic fraud is a thing.
- tiborsaas 3y agoWhat's the point with academic fraud at this level? If it's fraud, then what did they expect other than career suicide?
- RivieraKid 3y agoPlease explain the benefit of faking the result of this paper and destroying your reputation.
- Koiwai 3y agohttps://en.wikipedia.org/wiki/Ranga_P._Dias#Controversy https://en.wikipedia.org/wiki/Ranga_P._Dias#Controversy https://en.wikipedia.org/wiki/Haruko_Obokata#STAP_cell_controversy https://en.wikipedia.org/wiki/Haruko_Obokata#STAP_cell_contr... I don't really have an explanation other than they're simply crazy.
- XorNot 3y agoThat video isn't very convincing. The usual test is that the material can float above the magnet.
- deleted 3y ago[deleted]
- solarmist 3y agoThe effect is weak, but seeing that it behaves the same by flipping the magnet means that it can't be a standard magnet like we're used to seeing. (If I understood some of the other comments correctly). Other comments. https://news.ycombinator.com/item?id=36867758 https://news.ycombinator.com/item?id=36867758
- lilgreenland 3y agoCopper does this already. It's not like ferromagnets. https://www.youtube.com/watch?v=sENgdSF8ppA https://www.youtube.com/watch?v=sENgdSF8ppA
- deleted 3y ago[deleted]
- solarmist 3y agoIn the video, it's when they stop moving the magnet, it maintains its position, neither repelling nor attracting. Several physicists have spoken up and said this, and a few other tells distinguishes it from any conventional materials, which is why they made the video to begin with I'm sure. That said I'm just parroting back the things I've picked up from this discussion.
- piyh 3y agoUnmoving copper also neither repels or attracts a magnet. Eddy currents impede movement of non ferrous metals in a static magnetic field. This looks like slow motion falling or resistance to spinning when the metal is in a fixed field. This is how auto belays work. If you move the magnet, the metal will also move since you're inducing a current and the fields from the eddy currents will react against the moving magnet.
- mikewarot 3y agoI don't see anything special in that video, you're using eddy currents to exert forces on a conductive material. It wasn't levitating. Given the apparent size/strength of the magnets, you could probably replicate that with a silver coin
- swamp40 3y agoThe video text says: "The sample was thermally deposited on a copper plate." The video headline says: "Magnetic Property Test of LK-99 Film". That's how copper acts with a moving super magnet[0], so the video doesn't really show anything. [0] https://youtu.be/KrH3t1H6fOc?t=50 https://youtu.be/KrH3t1H6fOc?t=50
- pengaru 3y agoThe video shows that this is all bollocks
- floxy 3y agoThis is the better video: https://sciencecast.org/casts/suc384jly50n https://sciencecast.org/casts/suc384jly50n
- pengaru 3y agoWell it's at least not copper with its own eddy current reactions on display this time. But still rather unconvincing.. especially if this is the best they could produce as a levitation proof video to publish.
- eig 3y agoThat's not the video I'm referring to. It is a different experiment from Fig 4b in the paper, which is showing magnetic levitation. I agree with swamp40: the video you linked is not demonstrating the Meissner effect, and is just showing Lenz's law.
- concurrentsquar 3y ago> I really need someone to bring me down a notch. This is too exciting! It's on arXiv, which is a preprint journal, which means it has no peer-review; and is therefore generally less trustworthy (especially when the paper has no connection to a technical conference or is not being published elsewhere, and is in a non-computer science or mathematics field). In addition to this, claims of room-temperature superconductors have been mired in controversy or otherwise proven false: - http://www.superconductors.org/roomnano.htm http://www.superconductors.org/roomnano.htm (2004) - https://www.nature.com/articles/nature.2012.11443 https://www.nature.com/articles/nature.2012.11443 (2012) - https://www.scientificamerican.com/article/a-superconductor-scandal-scientists-question-a-nobel-prize-worthy-claim/ https://www.scientificamerican.com/article/a-superconductor-... (2018) - https://www.quantamagazine.org/room-temperature-superconductivity-claim-falls-apart-update-20201014/ https://www.quantamagazine.org/room-temperature-superconduct... (2020) - https://forbetterscience.com/2023/03/29/superconductive-fraud-the-sequel/ https://forbetterscience.com/2023/03/29/superconductive-frau... (2022-2023) Considering that many fraudulent claims of room-temperature superconductivity have gotten into Nature and other top-tier publications, I would wait for multiple independent recreations of the results in the paper.
- ahlCVA 3y agoThis seems to be the corresponding video (linked in the associated media tab on arXiv): https://sciencecast.org/casts/suc384jly50n https://sciencecast.org/casts/suc384jly50n
- tinco 3y agoIs there an alternative explanation possible for the video? Couldn't it just be a magnetized piece of ferrite that is magnetized in a weird way causing it to lift up like that on a strong magnet?
- achr2 3y agoPyrolytic graphite looks exactly like this and behaves in exactly this way (without being superconducting) as long as one side is anchored. With a careful array of magnetic poles, graphite will levitate at room temperatures.
- Koiwai 3y agoThe sheer size of the sample stuns me.
- fooqux 3y agoI'll get this out of the way first: I'm a couch scientist (even that is probably stretching it). That said, from the video it mentions the superconductor was applied as a film over copper. But wouldn't plain copper also exhibit this effect due to eddy currents? I fail to see how the (supposedly) thin film is affecting the plate in this experiment. I'm probably missing something and I hope someone can enlighten me.
- tkanarsky 3y agoIn a normal conducting material eddy currents dissipate relatively quickly. The shard of material in the magnet video appears to be floating quite stably for dozens of seconds, which implies that eddy currents are not being dissipated. I'm personally excited, I think it's the real deal but with some limits on maximum field strength and current