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Comment by RandallBrown | Hacker News Reader

Can someone explain how this video shows superconductivity?

[not an expert but...]It shows strong diamagnetism(being repelled by both of the poles of a magnet), which is a property of superconductors. Not necessarily a superconductor though, that’s still to be established but at least it shows that the inventors are up to something and it’s not complete fabrication.

Why don’t they try heating it and seeing if the effect goes away? You could even try a welding torch or something.

There are better, less destructive ways to test the transition temperature. Apparently LK-99 is hard to make in bulk, so they probably don't want to torch their sample.

or just stick it outside in a heat dome? don't you have one near you?

lol or a temperature chamber that the vast majority of labs have? heck I made a toaster oven that will go anywhere from 100F to 400F with an arduino and a $3 toaster oven from the junk store.

Not only is it a purported to be a room temperature super conductor, it's a relatively high temperature superconductor, not guarantee the effect goes away if you put it under a torch.

I think the critical temperature was 400 K (127 °C).

As far as I can tell, 127°C is just the highest temperature it was tested at. The critical temperature may be higher.

The original preprint said at least 400K. They didn't find an upper limit. And for some reason, they don't seem to have the standard impulse of "hey, our potentially revolutionary material that we've been working on for 20 years seems to actually be working. Let's check what happens when we set it on fire!"

The updated preprint gives Tc of 104.8 degC. I am not a material scientist and do not know much about superconductors, but cursory glance on some of the charts in the paper suggests that the real Tc of sample they measured is somewhat lower that that, but still well above room temperature.

I am no expert on this topic, but I feel this is similar to how ferrofluid forms "spikes" when placed near a magnet. Are they related?

I'm not an expert too but AFAIK ferrofluids are actually attracted by magnets. The spikes are probably as a result of having strong and weak locations of magnetic field and the the liquid rushing into those.

But yes, Maybe I'm interpreting the video wrongly. Yet, to me it looks like the bulky part of the sample is being repelled by both poles of the magnet as it stands upright with the pointy end at the bottom each time. IMHO if this was due to attraction, the pointy end would be at the top.

No. The spikes are pulled toward the magnet (ferromagnetism) whereas superconductivity is repelled by the magnet (diamagnetism.)

That’s a stretch. Dias’ material has real color change under high pressure which is an expected property of superconductors but nobody would argue his paper was not complete fabrication

There's all kinds of cool examples of this using liquid nitrogen to make a superconductor exhibit the Meissner effect.

The material in question will have these effects at room temperature and pressure.

https://youtu.be/HRLvVkkq5GE?t=53

It shows the magnetic effects associated with superconductors, which are omnidirectional from my understanding, in contrast to a 'regular magnet'

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