I'm still unclear. Why is the test limit 110K? If this is supposed to be usable at ambient temperature then this seems like not a useful finding. Is it just some artifact of how superconductivity is measured?
Some people say they can get it to work at room temperature, and others say they can't.
Testing a sample at superconductivity-friendly temperatures helps figure out whether there's something to investigate here, since most materials do not superconduct at any useful temperature.
Most materials are not superconductors at 110K. If this one is, it is possible Koreans did not fake room temperature results but rather their sample is slightly different for some reason, maybe pure luck, maybe some part of process that they didn't clearly define or that their precursor materials have certain impurities.
It is apparently extremely difficult to fabricate LK-99 and most of the time the process being used creates similar substances but without appropriate Cu substitution in its lattice. All of the videos have been of generally quite small samples and the manufacturing difficulty is the purported reason.
The SK also supposedly had more details on this but with the leak of the paper those haven't been cleaned up and added to the paper.
I thought the original hype around LK-99 was that it was supposed to be easy to manufacture with materials most labs have on hand? E.g. https://news.ycombinator.com/item?id=36865106
Amusingly, some friends asked me about it shortly after the original announcement. I'm not a superconductor person, but I am a materials person.
My response was, basically, the biggest risk (after toxicity) "is that they got lucky and there are subtle things they did that aren't in the recipe which will turn out to have been critical."
I've done a lot of materials research. It's pretty likely that they got lucky on a small percentage of the samples and spent years trying to figure out what on earth was different. I am excited that 10,000 other labs will stand a very good chance of finding out.
Exactly my take. The big question for me is whether or not they haven't accidentally included some contamination that makes all the difference or whether or not the geometry of the placement of the atoms is controlled tightly enough and whether either of those is going to make a huge difference in the outcome. And then there are a hundred different process errors that could have similar effects. This could take a while to be nailed down.
- It was naive to think a simple recipe was going to play out with everyone getting what they wanted easily when they tried to follow it.
- It's still a huge deal if the manufacturing is as easy as it appears to be, even if most of the replication attempts aren't getting _quite_ the right thing. It's hilarious if room temperature superconductors were always "Put these two things in a lucifer furnace and roll a die" away.
> It's hilarious if room temperature superconductors were always "Put these two things in a lucifer furnace and roll a die" away.
Is it, though? I mean it's hilarious sure but if we were to draw parallels to the mother of all elements, the celestial furnaces in the sky, it seems less wild.
It's extraordinary how many replication experiments are happening so quickly and how tantalizing the results are. It would be optimistic to say the original research was just going to unlock this tech for everybody at once but even if it's the clue that leads to dozens of refinements that eventually lands on a winning material then it's still a landmark event.
The consensus of this forum was absolutely that it's super easy to manufacture, any chemistry youtuber can do it, and that we are going to know whether it works or not within 48 hours.
I wonder if the people who steered the discussion just pretended to be experts or what happened. Where were the people who now in these threads explain the reasons why it is really difficult to bake? Or are those the same users?
Probably people who knew above average about the process and sourcing materials to realize you just had to throw some common stuff in a furnace but without being experts in material science.
Even then if it's tricky to do its most likely because the process is not well know/refined yet
The other day, about a third of top posts on hn where about this. I got the impression there was an organised campaign by the believers. The usual healthy skepticism was buried beneath the cheerleaders. Most top comments where along the lines "I never believed it. Until now".
The common understanding seems to be that producing true LK99 is very difficult as you need to get the crystal structure just right. Many samples probably have mixes of the correct and other structures. That's why some float and some don't. The sample might be quite "dirty", meaning the critical temperature is lower.
Seems like it may depend on getting specific binding sites.
> Finally, the calculations presented here suggest that Cu substitution on the appropriate (Pb(1)) site displays many key characteristics for high-TC superconductivity, namely a particularly flat isolated d-manifold, and the potential presence of fluctuating magnetism, charge and phonons. However, substitution on the other Pb(2) does not appear to have such sought-after properties, despite being the lower-energy substitution site. This result hints to the synthesis challenge in obtaining Cu substituted on the appropriate site for obtaining a bulk superconducting sample. [1]
I believe 110K is where it hit zero resistivity (the lower bound) but any increase from there and it was no longer presenting superconductivity.
If we are to trust the SK team, it's possible the design in the paper is outdated and in-house they have dialed it in to something stable at room temperature.
