Why are folks trying to prove that this material is a superconductor in roundabout ways, like levitation, dimagnetism, etc? What is the reason they don't just test to see if electrical current flows without resistance? Surely there is something I am missing here.
Successful room temperature ambient-pressure magnetic levitation of LK-99
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Re: Successful room temperature ambient-pressure magnetic levitation of LK-99
#22[deleted]
Re: Successful room temperature ambient-pressure magnetic levitation of LK-99
#23Wow, is this it? Is this the confirmation?
I believe there’s no way to stably suspend an object on permanent magnetic fields, so if this is stable and doesn’t fall down then it’s hard to argue superconductivity isn’t involved.
There are diamagnetic non-superconductors like pyrolytic graphite that can also evade Earnshaw's theorem, but this would be the first metal with this strength of diamagnetism at room temperature AFAIK.
Re: Successful room temperature ambient-pressure magnetic levitation of LK-99
#24Ok, didn't read it. What about electric resistance at room temperature ambient-pressure under critical current?
They said they are testing that next. Sounds like they wanted to get the initial results out.
Re: Successful room temperature ambient-pressure magnetic levitation of LK-99
#25Ok, didn't read it. What about electric resistance at room temperature ambient-pressure under critical current?
So far, from my understanding, the sample size of the material has been small enough it's been difficult to rule out resistance from corrosion on the contacts of the sensors, though I seem to recall a post not too long ago on here about resistance below the threshold of measurement around 100 degrees k.
The compound must be tricky to synthesize with a good degree of purity- I think we'll learn quite a bit more if someone manages to get a bigger sample than a flake the size of the point of a needle.
Re: Successful room temperature ambient-pressure magnetic levitation of LK-99
#26Why are folks trying to prove that this material is a superconductor in roundabout ways, like levitation, dimagnetism, etc? What is the reason they don't just test to see if electrical current flows without resistance? Surely there is something I am missing here.
They do both. But measuring the resistance of something that is that small is super hard because it will be close to zero anyway even if it isn't superconducting. So a larger sample would give much more conclusive results.
Re: Successful room temperature ambient-pressure magnetic levitation of LK-99
#27There have been quite a few papers about LK-99, but the only thing I want to see is whether we observer sudden drop of resistance to zero below the critical temperature that is well above the room temperature at ambient pressure or not. So far, I haven't seen one.
Re: Successful room temperature ambient-pressure magnetic levitation of LK-99
#28Why are folks trying to prove that this material is a superconductor in roundabout ways, like levitation, dimagnetism, etc? What is the reason they don't just test to see if electrical current flows without resistance? Surely there is something I am missing here.
I have heard people much more knowledgeable than me say that measuring true zero resistance is actually quite difficult and takes some degree of specialized equipment, especially with such small samples. That may be part of it.
Re: Successful room temperature ambient-pressure magnetic levitation of LK-99
#29Why are folks trying to prove that this material is a superconductor in roundabout ways, like levitation, dimagnetism, etc? What is the reason they don't just test to see if electrical current flows without resistance? Surely there is something I am missing here.
It’s difficult to rule out external factors - a badly attached probe could also result in zero resistance for example.
Showing diamagnetism is one of the least error-prone ways to demonstrate the superconductor effect.
That’s my understanding anyway.
Re: Successful room temperature ambient-pressure magnetic levitation of LK-99
#30Why are folks trying to prove that this material is a superconductor in roundabout ways, like levitation, dimagnetism, etc? What is the reason they don't just test to see if electrical current flows without resistance? Surely there is something I am missing here.
It's difficult to produce a sample large enough and pure enough to have its resistance measured.