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Ferromagnetic half levitation of LK-99-like synthetic samples

arxiv.org

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Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#21

Post by dralley »

VHRanger wrote: post #11
carabiner wrote: post #9

Earlier quoted context omitted.

People 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.

How 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.

Checking the original samples, for one.

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#22

Post by jefftk »

VHRanger wrote: post #11
carabiner wrote: post #9

Earlier quoted context omitted.

People 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.

How 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.

Couldn't there be solid evidence that the observed behavior was due to a different effect?

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#23

Post by jgtrosh »

arpowers wrote: post #7

My main concern: Where are the original authors and why are they not helping people synthesize the replications?

According 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.

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#25

Post by carabiner »

xqcgrek2 wrote: post #6
freeone3000 wrote: post #3

So a completely different compound in a completely different shape.

The XRDs are nearly identical. It's a dead horse.

XRD 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/16872357567027527...

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#26

Post by protastus »

VHRanger wrote: post #4

After 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_megat...

The SNR of this saga is very low. A speck of something floating under a magnetic field on a blurry video is not proof of room temperature superconductivity. We've seen memes, jokes, shitposting, bravado, Soviet fan fiction, play-by-play updates from non-SMEs cooking stuff under improvised conditions. No actual resistance measurement of LK-99 with a 4 point probe.

If this is real, then discoverers found this in 1999, apparently couldn't synthesize with good yield, couldn't analyze rigorously, sat on the discovery for 24 years, were recently rushed to publish half-baked papers, and are now silent. None of this inspires confidence.

LK-99 could hypothetically be the real deal, and I want to believe, but I'm patiently waiting for people who actually know what they're doing to offer experimental evidence.

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#27

Post by [deleted] »

jefftk wrote: post #22
VHRanger wrote: post #11

Earlier quoted context omitted.

How 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.

Couldn't there be solid evidence that the observed behavior was due to a different effect?

[deleted]

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#28

Post by throwawaymaths »

GuB-42 wrote: post #13
freeone3000 wrote: post #3

So a completely different compound in a completely different shape.

Yes, 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…

This 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.

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#29

Post by jacquesm »

dralley wrote: post #21
VHRanger wrote: post #11

Earlier quoted context omitted.

How 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.

Checking the original samples, for one.

I 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.

Re: Ferromagnetic half levitation of LK-99-like synthetic samples

#30

Post by delabay »

throwawaymaths wrote: post #20
versteegen wrote: post #10

Earlier quoted context omitted.

Yes. 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.

For 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.

all 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.

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