What is LK-99, the subject of this paper:
https://www.kci.go.kr/kciportal/landing/article.kci?arti_id=ART002955269#none
I am interested only in its behavior at near room temperature and ambient pressure per discussion in the comments.
Resolves based on my best estimation at the end of this year. I will base my opinion on the consensus of expert condensed matter researchers.
Edit 2022-08-01 15:23:00 EST:
To clarify further, the "Some type of superconductor, but not at room temperature with near-ambient pressure." is NOT going to be the winner. It is not mutually exclusive with the other options, degrading the market. You can sell it down to zero for free Mana. Do NOT buy that option.
If the Meissner effect videos were taken with the material super-cooled, and the material is otherwise uninteresting I will rule as "a complete fabrication". If the videos were taken super-cooled. and the material is a powerful diamagnet at room temp, I will resolve diamagnet.
EDIT 2022-08-01 15:37 EST:
My goal is for the top choices at the end to be mutually exclusive and reasonably comprehensive. To that end, I may introduce new choices that are more descriptive and mutually exclusive and/or choose to NOT resolve in favor of existing choices. For example, if someone points out (hypothetically) that Type I and Type III SC's are not mutually exclusive or something, I may create a new option that rescues mutual exclusivity and choose NOT to pick either of those options. In addition, if there is a new option that comes to light in peer review, I am likely to make an option for it -- rather than letting the market simply resolve as "Other".
EDIT 2022-08-08 00:04:00 EST
Consider the three types of magnetism as a set S = {diamagnetism, paramagnetism, ferromagnetism}. The lack of a specific member of set S in an answer choice is understood to mean its absence in LK-99. I will also resolve the question in favor of the most specific descriptor. For example, if LK-99 is found to be ferromagnetic and powerfully diamagnetic, I will resolve in favor of the answer choice that has both of these. If the amount of a certain kind of magnetism is de minimis (ie non-exotic, commonly found in other materials), I may ignore it. For example, if LK-99 is only very slightly paramagnetic, I may choose to ignore that aspect of it in determining the answer.
EDIT 2022-08-29 19:30:00 EST
This paper suggests to me that LK-99 is in the normal range of diamagnetism for an insulator, but shows an interesting amount of ferromagnetism (which would be an important component in explaining the partial levitation). The research was done to a high standard and the purity is unsurpassed per XRD, so this is pretty strong evidence (albeit not conclusive). I'm unlikely to resolve this market until we see peer reviewed papers.
https://arxiv.org/pdf/2308.06256.pdf
Notably, if we see superconductivity when synthesized as a thin film, I will likely resolve in favor of one of the superconducitivity choices -- even if the bulk material is conclusively shown to not be superconducting.
Related questions
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@Joshua I am leaning towards resolving it as "Both diamagnetic and ferromagnetic, but not superconducting". I clarified in a comment earlier that I view any amount of ferromagnetism in this lead-based compound to be "interesting", and the preprint Chris posted also mentions it https://arxiv.org/pdf/2308.06256.pdf . In addition, the presence of ferromagnetic regions may play a role in the ubiquitous levitation videos we saw, so it's also part of the narrative. It seems to be among the strongest diamagnetic materials outside the superconductors, so I view both diamagnetism and ferromagnetism as important properties of the material. Consensus seems to think any paramagnetism is from impurities, and I don't see high quality independent evidence of superconductivity of any type. Inshallah, we find that in the thin film someday, but I gotta resolve the market soonish.
If no significant objections, I will resolve tomorrow EOD.
@aashiq I was under the impression that the ferromagnetism was credibly thought to be from iron impurities in the samples after grinding in a standard mortar/pestle?
@aashiq I think the problem with that resolution is that "a totally uninteresting material, a total fabrication" can't possibly be true. If diamagnetism and ferromagnetism make a material interesting then every material is interesting.
@MarcusAbramovitch It's interesting to me that a lead-based compound is the third strongest diamagnetic material on the planet, outside of superconductors and a ferromagnet to boot.
@QuantumObserver The linked preprint seems to think that it's not solely impurities, but admits they cannot conclusively rule them out. They would have to be below the threshold of XRD though. I'm open to seeing more evidence in favor of impurities as it concerns ferromagnetism though.
@MarcusAbramovitch in an earlier comment, I wrote that if LK-99 is the strongest known diamagnetic material, i would consider it diamagnetic. I also said that the threshold could be somewhat lower, but that I would think on it a bit and see.
So far looking like it's a little bit weaker than Bismuth, placing it about third. It's about 1/3 as diamagnetic as pyrolytic carbon, which I would have easily resolved as diamagnetic.
I would be open to other evidence about its diamagnetism as well.
@aashiq I think you have given a fair and decent explanation for your resolution. I think the market was slightly poorly formed but that's very hard to do well in this case.
@MarcusAbramovitch How do we feel about partial resolutions? Given the continuing uncertainty and the points raised, I think that's a better reflection of the truth at this point in time. Maybe something like 30% uninteresting, 30% diamagnetic, 30% ferromagnetic + diamagnetic, 10% just ferromagnetic (to reflect the view that this is a lame amount of diamagnetism)
@aashiq Im cool with partial resolutions. I also think you've explained yourself enough that ill be cool with any resolution
@dgga I can't believe you're betraying your loyalty to rationalussy, and rationalussy superconductivity in particular, by betting NO here.
I bought and then sold this bet, (NO on it being a powerful diamagnet), I think it was too hasty. I had bet NO thinking its diamagnetism wasn't "powerful", but now I'm not so sure.
I'm unsure what the threshold for "powerful" diamagnet might be, or what sorts of confirmation of observations is required to judge this true. The preprint Wikipedia cites for the pure crystal form being diamagnetic actually says it's reasonably strong:
Nowhere near superconductor-level, but if that measurement is accurate (and the authors seem to be hedging a bit, sounds like it might be an error-prone measurement), then it's something like (I think) the third most diamagnetic non-superconducting material we know of (all of which are ~4 orders of magnitude less diamagnetic than superconductors). This is surprising and generally I would want some more confirmation before believing it.
It seems that the partial levitation was mostly explained by ferromagnetism, but nonetheless the pure crystal form may be reasonably diamagnetic.
@aashiq perhaps you can clarify - if the different outcomes of synthesis have different properties (the pure, translucent crystal vs other "phases" of LK-99 you can get from more-or-less following the recipe), which are we talking about? And what's the threshold for "powerful" diamagnetism? Something approaching the level of diamagnetism in superconductors? Or is a reasonably strong diamagnetic response comparable to that of Bismuth sufficient?
@chrisjbillington If it’s the third most diamagnetic thing, that counts as powerful imo.
In terms of phases, I guess I’m biased in favor of purity — except if they synthesize anything that’s a superconductor, I’m going superconductor
@aashiq I hope my new answer is specific enough. Based on the replication attempts that have been made (https://en.wikipedia.org/wiki/LK-99#Experimental_studies), it looks like the material is not powerfully diamagnetic, but is either weakly diamagnetic, or only diamagnetic in some circumstances.
I'm not sure whether I would resolve in favor of "An uninteresting material" or your answer...
@AashiqDheeraja27e "Potentially only diamagnetic under certain circumstances (e.g., depends on the amount of impurities)" kind of sounds like you still don't know if it's diamagnetic.
Does a paper such as the one I link in this comment, which reports the coexistence of weak ferromagnetism count toward FM+diamagnetism, just FM, or “uninteresting”?
https://manifold.markets/QuantumObserver/will-the-lk99-room-temp-ambient-pre#7iOoy9yAbUyNZ3IFB1W0
@QuantumObserver I feel like any degree of FM in pure LK-99 is pretty interesting. What do you think?
@aashiq I, an idiot, would probably agree! Would not have expected an FM phase from materials without Fe, Ni, or other ferromagnetic materials
@QuantumObserver Separately do you know how to buy this beautiful purple LK-99? https://media.nature.com/lw767/magazine-assets/d41586-023-02585-7/d41586-023-02585-7_25924888.jpg?as=webp