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LK-99: Team of Southeast University observed zero resistance below 110 K

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Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#201

Post by jacquesm »

grandpa wrote: post #180
alephnerd wrote: post #172

Earlier quoted context omitted.

What's the name of this book? It sounds really cool! Any other recommendations on books about the history of MatSE/Chemistry?

The title is "Excuse me sir, would you like to buy a kilo of isopropyl bromide?" https://archive.org/details/gergel_isopropyl_bromide

That's a hilarious book: "There was a jar which I had not noticed before containing potassium metal. I knew that potassium was a silvery metal, but this was one inch spheres, green with the oil in which they were immersed. I removed two for a collection of elements we were starting at Columbia High, scraped off the oil and put the marbles in my handkerchief which I added to a collection of miscellaneous glassware in my back pocket. "

Oops... I can see where that is headed.

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#202

Post by hatsunearu »

baq wrote: post #179
hatsunearu wrote: post #103

The Fig 3a)b) graphs are not showing superconductivity. That just looks like the resistance dips below the ~1e-5 mark and goes goes deep into the noise. That just looks like a normal conductor that has a positive temperature coefficient. edit: to add speculation, I think they made something that's not quite LK-99, and it's behaving like a normal conductor with no superconductance.

What would be the acceptable noise floor here?

that's the wrong way to look at this.

what i see in this noisy measurement is nothing interesting. that always means:

a) the noise is obscuring something interesting

b) there is nothing interesting

for a), if it's practical and/or likely that there is something interesting in the noise, I'd try to find a way to lower the noise (or SNR).

you would assert b) if you have some strong convictions that there's nothing interesting down there.

Since the assertion that LK-99 is superconducting at room temp, there's already enough data to say that this is either A) whatever they measured is not LK-99 B) whatever they measured is LK-99, but doesn't superconduct at room temp.

Their ridiculous interpretation pointing at the SNR=1 point saying that's the critical temperature is actually hilarious.

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#203

Post by overnight5349 »

Palpatineli wrote: post #119
matsemann wrote: post #113

Earlier quoted context omitted.

It doesn't invalidate the original claim, as they haven't been able to make a pure sample to test with, as I understand it. Or at least that there is some difference between their samples and the others, but still it shows promise.

[flagged]

Purity would affect superconduction. Consider grains of superconducting material embedded in a matrix of regular conductive metal.

One of the theories for the behavior of this material explains that the copper atoms preferentially form a structure that does not superconduct. The structure that does superconduct is tricky to achieve due to the energy levels. (Paraphrased summary)

It's likely that a poorly prepared sample will have discontinuous regions of both superconducting and non-superconducting material. If that is the case, you won't observe superconduction.

It may be that the non-superconducting material does superconduct at low temperatures, which would mask the purity problem.

The truth is that quite literally nobody fully understands what's actually happening here. That's kind of the point of all this experimentation

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#204

Post by tigershark »

carabiner wrote: post #193
d1str0 wrote: post #178

Earlier quoted context omitted.

Assuming they discovered a low cost, room temperature, room pressure, superconductor, there are many HUGE technological advancements that can be made that would impact your daily life. Possibilities include improved battery longevity in all devices(probably in an order of magnitude), low friction transport improvements (ie. cheaper high speed rail), and faster and higher bandwidth wired connections. https://en.wikipe…

No I mean why is this "huge" when each time that's happened it's been deflated within 12 hours: - initial LK-99 paper upload on Arxiv: HUGE, then it's probably nothing until replication (waiting) - DFT release: HUGE, then probably nothing (DFT has poor predictive power) - 110K SC: HUGE, then ... ? In every case it's been the laymen saying HUGE, then the experts saying it's probably insignificant. Then the laymen sett…

[flagged]

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#205

Post by cyberlurker »

freitzkriesler2 wrote: post #173
modeless wrote: post #121

To me this is encouraging. 110K is really high! It's higher than YBCO which is what they make commercial "high temperature" superconducting tape out of. IMO if this is legit (I have no way of judging the source) then this is the first good third party evidence that the original researchers are not just doing some kind of fraud. A total fraud wouldn't have actually discovered a novel high-temperature, but not room tem…

What's impressive to me is how simple making it is. There are still low hanging scientific discoveries that are out there but that we haven't figured out yet.

Like ancient Roman concrete.

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#206

Post by klimt »

This is my first comment on this material, because I've been skeptical, but this result shouldn't be understated. It basically confirms the existence of a new family of high-temperature superconductors, the first of its kind since the cuprates in 1986. And for context, in the initial paper on the cuprates the critical temperature was measured to be 36 K. By synthesising other members of the cuprate family and optimising the growth, it was possible to raise it to 127 K in the subsequent few years. The 110 K seen today for LK-99 sets a baseline, and it's a very good baseline at that. Confirm me as excited.

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#207

Post by vl »

carabiner wrote: post #169
saberdancer wrote: post #131

Huge news. This means it is not a scam as a discovery of this type of superconductor would be big enough. It also means it is unlikely they were measuring wrong for multiple years. My layman take is that Korean sample is just a better or different batch that is properly superconducting at room temperature.

As a layman, how do you know this is huge?

I don’t know why people say it’s huge, so far all the images released show it is tiny.

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#208

Post by saberdancer »

carabiner wrote: post #169
saberdancer wrote: post #131

Huge news. This means it is not a scam as a discovery of this type of superconductor would be big enough. It also means it is unlikely they were measuring wrong for multiple years. My layman take is that Korean sample is just a better or different batch that is properly superconducting at room temperature.

As a layman, how do you know this is huge?

Until today main hypothesis was that it is a scam by original team or a mistake when measuring resistance.

Now it looks unlikely as it would be very strange to luck into a new superconductor (pretty "good" one too) if they were faking it. It also means it is unlikely they made fundamental measuring mistakes such as thinking the sample is in room temperature when it was at 100K.

What seem plausible is that the process to make the material is not well defined and that there is high degree of variability. Even this chinese 110K replication only one of 6 samples shows superconductivity, meaning there is much room for improvement, perhaps with fine tuning they will find sample with characteristics that Korean team observed.

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#209

Post by jacquesm »

bloopernova wrote: post #185
jacquesm wrote: post #31

Earlier quoted context omitted.

It is and it isn't. It's at ambient pressure (which is something useful), and there is something very odd happening much higher up that needs to be explained. They say their sample purity is higher than the one the Korean team had, so that would normally lead to better yield and easier confirmation of the superconductivity. But since it does show the Meissner effect in other samples as well at room temperature there…

I adore stories that include the phrase "that's odd" or "something odd happens when ..." Even if we don't get the astonishing result originally claimed by the rogue paper, it's still a triumph of science in my ignorant opinion.

And sometimes 'that's odd' leads to things larger than the original goal. You really don't want to hear those words in the doctors' office though.
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