LK99 -- A new room temperature superconductor?

Quote from Ahlfors

No Sweden Industrial executive

I meant the person who wrote the story, not the creator of the sample. You can consider it fiction if you wish.

Edit to add: I had the country of origin wrong, the person was Dutch, not Swede.

Here is a recent video of an apparently successful LK99 replication:
https://www.douyin.com/video/7263715495256378659

Some people have been wondering whether LK99 is a proper superconductor, or a highly conductive oxide material that also happens to be diamagnetic. The above video looks to me like flux pinning, not just diamagnetic levitation. Comments?
Also, the authors of a recent replication (https://arxiv.org/abs/2308.01516) claim diamagnetic transition in the 320 - 340 K range. I assume that transition also makes superconductivity more likely than inherent diamagnetism, isn't it so?

There are some LENR theories which propose that superconductivity catalyzes LENR. Now it might be easier to test that hypothesis.

i went in a conference about superconductors maybe 10 years ago or maybe more..

i have seen a demo with a magnet a bigger superconductor ( several cm3) and teh staff put on this liquid N2 i think.

Aftter a very short time the team removed the spacer they used to maintain the sample with a gap regarding the magnet.

Me of the other people were able to touch and compress with my hand the superconductor close to the magnet..

It was really impossible to reduce the gap between them even with almost my entire weight..

All of this this, i'm dubitative on this video than the man is able to bring closer the sample to the magnet with only this rod in hand.

Quote from Andras

Here is a recent video of an apparently successful LK99 replication:
https://www.douyin.com/video/7263715495256378659

Some people have been wondering whether LK99 is a proper superconductor, or a highly conductive oxide material that also happens to be diamagnetic. The above video looks to me like flux pinning, not just diamagnetic levitation. Comments?
Also, the authors of a recent replication (https://arxiv.org/abs/2308.01516) claim diamagnetic transition in the 320 - 340 K range. I assume that transition also makes superconductivity more likely than inherent diamagnetism, isn't it so?

There are some LENR theories which propose that superconductivity catalyzes LENR. Now it might be easier to test that hypothesis.

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Professor Simon Clarke Oxford University discusses LK99.

i have to add about this experiment i described previously, that the superconductor was "linked" with the magnet even if separated by an 2 cm air gap. i was able to displace in 3 axis the magnet or the superconductor part , they maintained this gap exactly as the spacer defined the distance. if a smaller gap have been this one would be kept. the only possibility of relative mobility was a relative rotation around the Z axis between these parts but no influence on the gap.

Iw as lucky to see and touch by myself, very non conventional behavior, maybe E.T ahaha.

Quote

The above video looks to me like flux pinning, not just diamagnetic levitation. Comments?

Unfortunately the sample doesn't stay in changed orientation - it returns back, albeit quite slowly which would indicate high conductivity (like slab of cooled copper above magnet). Which is on other hand the effect difficult to fake at room temperature.

BTW even if the sample would return to its original orientation very slowly - which would imply high intrinsic conductivity - it still may not be a good superconductor, as such a material may be formed with so-called "pseudogap" phase composed of many superconductive islands, which are highly conductive by itself - but poorly connected mutually. Which would render it unusable for "classical" application of superconductors where high currents are used - but in less conventional ones (like reaction-less drives and scalar wave reflectors/lenses/generators which don't pass current through material) it wouldn't pose so great problem.

China Science Preprint Paper Claims Successful LK-99 Replication and Levitation and Expectation of Useful Room Temperature Superconductors

China Science Preprint Paper Claims Successful LK-99 Replication and Levitation and Expectation of Useful Room Temperature Superconductors | NextBigFuture.com

Huazhong University of Science and Technology has published a preprint paper on Arxiv that claims successful growth and room temperature ambient-pressure

www.nextbigfuture.com

Huazhong University of Science and Technology has published a preprint paper on Arxiv that claims successful growth and room temperature ambient-pressure magnetic levitation.

The chinese team from HUST has successfully for the first time verify and synthesize the LK-99 crystals which can be magnetically levitated with larger levitated angle than Sukbae Lee’s sample at room temperature. They state it is expected to realize the true potential of room temperature, noncontact superconducting magnetic levitation in near future.

The History of Superconductors.

Working in the Lab.

SUCCESS!! LK99 Lab Update - Our Process Explained in Detail

Many already saw this video posted to YT and Twitter this morning showing our sample of LK-99 apparently exhibiting diamagnetism - as with the Chinese replic...

www.youtube.com

Looks like the LK-99 is a no go.

Well, Seems Like LK-99 Isn’t a Room Temperature Superconductor After All (msn.com)

Good thing we have the life changing e-cat EV demo in Italy coming up soon.

That couldn't possible by a flop.

Quote from PhysicsForDummies

Looks like the LK-99 is a no go.

Well, Seems Like LK-99 Isn’t a Room Temperature Superconductor After All (msn.com)

Good thing we have the life changing e-cat EV demo in Italy coming up soon.

That couldn't possible by a flop.

I stopped paying attention to mainstream articles telling anything conclusive years ago. They never get anything right.

Another documented replication on Twitter with negative results for the Meisner effect and type1 super conductivity.
This doesn't mean it's still not an interesting meta-material, and might have flux pinning properties.
Here is the link: Meisner or Bust

Keep in mind the replication could have been done poorly to cause the Fe contamination. The original paper https://arxiv.org/ftp/arxiv/papers/2307/2307.12008.pdf make no mention of Iron contamination in there

X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Electron Paramagnetic Resonance Spectroscopy (EPR) spectroscopies. It seems it would have been an important thing to mention how to avoid Fe contamination from the Lead Apatite.

UP Date.

LK99 August 11 Updates | NextBigFuture.com

UPDATE: Hyun Tak Kim has put out news slides that describes a semiconductor and superconductor phase for LK99. He quoted his own paper on VO2 to explain that

www.nextbigfuture.com

Persistence.

It's all a bit too technical for me but might be of interest to others...

Current percolation model for the special resistivity behavior observed in Cu-doped Apatite

Since the initial report of the potential occurrence of room-temperature superconductivity under normal pressure [arXiv: 2307.12008], there has been…

arxiv.org

Final nail in the LK99 coffin?

LK-99 isn’t a superconductor — how science sleuths solved the mystery

Replications pieced together the puzzle of why the material displayed superconducting-like behaviours.

www.nature.com

Impure samples

In their preprint, the Korean authors note one particular temperature at which LK-99’s showed a tenfold drop in resistivity, from about 0.02 ohm-centimetres to 0.002 ohm-cm. “They were very precise about it. 104.8ºC,” says Prashant Jain, a chemist at the University of Illinois Urbana–Champaign. “I was like, wait a minute, I know this temperature.”

The reaction that synthesizes LK-99 uses an unbalanced recipe: for every 1 part copper-doped lead phosphate crystal — pure LK-99 — it makes, it produces 17 parts copper and 5 parts sulfur. These leftovers lead to numerous impurities — especially copper sulfide, which the Korean team reported in its sample.

Jain, a copper-sulfide expert, remembered 104ºC as the temperature at which Cu₂S undergoes a phase transition. Below that temperature, the resistivity of air-exposed Cu₂S drops dramatically — a signal almost identical to LK-99’s purported superconducting phase transition. “I was almost in disbelief that they missed it.” Jain published a preprint⁷ on the important confounding effect.

On 8 August, the CAS team reported on the effects of Cu₂S impurities in LK-99. “Different contents of Cu₂S can be synthesized using different processes,” says Jianlin Luo, a CAS physicist. The researchers tested two samples — the first heated in a vacuum, which resulted in 5% Cu₂S content, and the second in air, which gave 70% Cu₂S content.

The first sample’s resistivity increased relatively smoothly as it cooled, and appeared similar to samples from other replication attempts. But the second sample’s resistivity plunged near 112 ºC (385K) — closely matching the Korean team’s observations.

“That was the moment where I said, ‘Well, obviously, that’s what made them think this was a superconductor,’” says Fuhrer. “The nail in the coffin was this copper sulfide thing.”

Making conclusive statements about LK-99’s properties is difficult, because the material is finicky and samples contain varying impurities. “Even from our own growth, different batches will be slightly different,” says Li. But Li argues that samples that are close enough to the original are sufficient for checking whether LK-99 is a superconductor in ambient conditions.

Crystal clear

With strong explanations for the resistivity drop and the half-levitation, many in the community were convinced that LK-99 was not a room-temperature superconductor. But mysteries lingered — namely, what were the material’s actual properties?

Initial theoretical attempts using an approach called density functional theory (DFT) to predict LK-99’s structure had hinted at interesting electronic signatures called ‘flat bands’. These are areas where the electrons move slowly and can be strongly correlated. In some cases, this behavior leads to superconductivity. But these calculations were based on unverified assumptions about LK-99’s structure.

To better understand the material, the US–European group⁵ performed precision X-ray imaging of their samples to calculate LK-99’s structure. Crucially, the imaging allowed them to make rigorous calculations that clarified the situation of the flat bands: they were not conducive to superconductivity. Instead, the flat bands in LK-99 came from strongly localized electrons, which cannot ‘hop’ in the way a superconductor requires.

On 14 August, a separate team, at the Max Planck Institute for Solid State Research in Stuttgart, Germany, reported⁶ synthesizing pure, single crystals of LK-99. Unlike previous synthesis attempts that relied on crucibles, the researchers used a technique called floating zone crystal growth that allowed them to avoid introducing sulfur into the reaction, eliminating the Cu₂S impurities.

The result was a transparent purple crystal — pure LK-99, or Pb_8.8Cu_1.2P₆O₂₅. Separated from impurities, LK-99 is not a superconductor, but an insulator with a resistance in the millions of ohms — too high to run a standard conductivity test. It shows minor ferromagnetism and diamagnetism, but not enough for even partial levitation. “We therefore rule out the presence of superconductivity,” the team concluded.

The team suggests that the hints of superconductivity seen in LK-99 were attributable to Cu₂S impurities, which are absent from their crystal. “This story is exactly showing why we need single crystals,” says Pascal Puphal, a specialist in crystal growth and the Max Planck physicist who led the study. “When we have single crystals, we can clearly study the intrinsic properties of a system.”

Lessons learned

Many researchers are reflecting on what they’ve learned from the summer’s superconductivity sensation.

For Leslie Schoop, a solid-state chemist at Princeton University in New Jersey, who co-authored the flat-bands study, the lesson about premature calculations is clear. “Even before LK-99, I have been giving talks about how you need to be careful with DFT, and now I have the best story ever for my next summer school,” she says.

Jain points to the importance of old, often overlooked data — the crucial measurements that he relied on for the resistivity of Cu₂S were published in 1951.

While some commentators have pointed to the LK-99 saga as a model for reproducibility in science, others say that it’s an unusually swift resolution of a high-profile puzzle. “Often these things die this very slow death, where it’s just the rumors and nobody can reproduce it,” says Fuhrer.

When copper oxide superconductors were discovered in 1986, researchers leapt to probe their properties. But nearly four decades later, there is still debate over the material’s superconducting mechanism, says Vishik. Efforts to explain LK-99 came readily. “The detective work that wraps up all of the pieces of the original observation — I think that’s really fantastic,” she says. “And it’s relatively rare.”

IMO copper sulphide shouldn't be present in material at all: in my theory superconductivity would require presence of highly oxidized lead/copper atoms (which attract and concentrate electrons along their lines) - and sulphide ions would reduce them. So that once you have copper sulphide presented in the sample, it just means that it can not be a superconductor. Cuprate superconductors require long time annealing in oxygen atmosphere during last stage of their preparation. Under such a conditions all traces of sulphide anions would be destroyed.

German Scientistd say not a Super Conductor.

South Korea’s LK-99 not superconductor: German scientists | Taiwan News | 2023-08-17 16:47:00

Room-temperature superconductor, holy grail of scientific world, remains elusive | 2023-08-17 16:47:00

www.taiwannews.com.tw

Quote from sam12

German Scientistd say not a Super Conductor.

This was clear from the beginning. With no flying saucer - full Meissner Effect - it can not be a regular SC. But also the axial (1D) version could be excluded as the resistance is far to high.