Room-temperature superconductor

[KE5FX]

Claimed critical temperature is 127C:

https://arxiv.org/abs/2307.12008

[tszaboo]

Comments turned off, unlisted video, of a channel having zero videos uploaded...
I'm a bit skeptical.

[WatchfulEye]

Better video with link to a different pre-print manuscript:
https://sciencecast.org/casts/suc384jly50n

[KE5FX]

(a) not a product

So?

(b) not a dodgy technology

If it works, it will be hugely important.  Not usually how this sort of breakthrough appears, though.

[coppice]

We got the lead out of solder, and now it could be back in the wires themselves.

[KE5FX]

(a) not a product

So?

You posted in the wrong forum.

You'll get over it.

[Marco]

The lump being repelled by the magnet is a bit more indicative of diamagnetism, but they could just hammered a chunk off a hard ferrite magnet.

[Dr. Frank]

The paper contains some odd descriptions.
It's not clear, how they have practically measured the supposed electrical superconductivity.
There is no picture of the setup, the instruments used, the geometry, structuring and contacting of the probes, was it a film or bulk sample, what real voltages had been observed, i.e. @ 100mA (very high current for such experiments at usual samples)  did they measure nV? Therefore, I can't reproduce their conductivity values.

The stricter criterion is measuring magnetic susceptibility χ' = ∂M/∂H, which is exactly -1 in case of superconductivity (that's the said Meissner effect).
That strange magnetization measurement with a supposed SQUID, how have they done that?
They measure the magnetization in "emu/g", which is an ancient, I think non SI unit nowadays, and not very convincing.. The material could be a little bit diamagnetic only..
There is no steep susceptibility step, and that measurement is not related to any geometric property.
 Why do they measure H in Oerstedt, instead of A/m? Why don't they show a measurement in zero magnetic field, or only the Earth's magnetic field of < 50µT (0.5Oe) ?

If you have a SC sample in the form of a small rod, or a thin film of a given area, you can always calculate the expected output signal of your susceptometer (SQUID or e.g. AC Hartshorn bridge) and normalize that to confirm that χ' equals exactly -1.

Has this paper already been Peer reviewed?

I'm not convinced at all.

Frank

[Marco]

If it's not an outright hoax (which is the most likely explanation) the material is still very special.

A homogeneous material which is not a superconductor, acting as a magnetic field dependent brick wall current limiter could be useful.

[switchabl]

It looks like they already published their claim in what appears to be a rather obscure Korean journal a couple of months ago (http://doi.org/10.6111/JKCGCT.2023.33.2.061). Which is ... let's just say, it seems like a weird thing to do for something of this magnitude.

In any case, this would be such a big deal, even if it were published in Nature, I would definitely want to wait for several others to replicate the results.

[BrianHG]

  He is demonstrating Lenz's law, nothing else.  Any copper or aluminum or silver would demonstrate the same motion when exposed to a strong moving magnetic filed.

Here is an extreme example:

https://youtu.be/g0amdIcZt5I?t=442

How is it possible here at EEVBlog, no one knows about Lenz's law, or recognize that this is what happens when you move a magnet in front a copper coin.

[KE5FX]

It maintains its distance when he stops moving the magnet.

Agreed, though, almost everything about this screams "Hoax."  Hence the choice of forum.  I hope I'm wrong, of course!

[thm_w]

There is a levitation video here: https://sciencecast.org/casts/suc384jly50n
But as someone points out in the comments, non-superconductors are also able to do the same thing.

I don't know if the magnet "test" is actually proving anything? Or is it just testing the properties of the material.

[MT]

Bismuth and Graphene as well.

[BrianHG]

It maintains its distance when he stops moving the magnet.

Agreed, though, almost everything about this screams "Hoax."  Hence the choice of forum.  I hope I'm wrong, of course!

LOL, it only looks that way because of when the video starts, the magnet is already in motion.  You don't know the true angle of the camera, now do you?
Otherwise, he would push and hold the magnet right against the sample just to show us it would keep it's distance even at an angle.  And like others said, there can be a tiny bit of diamagnetic material within as well as the existence of conductive copper colored diamagnetic metals exist as well.  The vast majority of the effect illustrated perfectly fits Lenz's law.

[KE5FX]

It maintains its distance when he stops moving the magnet.

Agreed, though, almost everything about this screams "Hoax."  Hence the choice of forum.  I hope I'm wrong, of course!

LOL, it only looks that way because of when the video starts, the magnet is already in motion. 

(Shrug) At 0:09 and 0:30 the magnet is being held still near the sample for long enough to demonstrate that minimal, if any, net attraction or repulsion is taking place.  Note that the polarity of the magnet has been reversed between those two timestamps. 

I don't know of anything else that will behave exactly that way... but I'm not exactly an SME, to put it charitably.  If it's a hoax, which my money says it is, it's an inexplicably-deliberate one that will torpedo numerous careers at the institution involved.

[BrianHG]

It maintains its distance when he stops moving the magnet.

Agreed, though, almost everything about this screams "Hoax."  Hence the choice of forum.  I hope I'm wrong, of course!

LOL, it only looks that way because of when the video starts, the magnet is already in motion. 

Note that the polarity of the magnet has been reversed between those two timestamps. 

... Lenz's Law doesn't care about magnetic polarity...
Ok, enough, I'm out...

[gnuarm]

It looks like they already published their claim in what appears to be a rather obscure Korean journal a couple of months ago (http://doi.org/10.6111/JKCGCT.2023.33.2.061). Which is ... let's just say, it seems like a weird thing to do for something of this magnitude.

In any case, this would be such a big deal, even if it were published in Nature, I would definitely want to wait for several others to replicate the results.

One of the videos shows what appears to be a brittle material.  Does anyone know how this can be used in practical applications?

[Marco]

Thin films could be flexible enough.

[gnuarm]

Thin films could be flexible enough.

Is there any reason to expect this material could be formed into a thin film?

Superconduction has limits on various factors, so I believe there is still minimum sizes required depending on the application.

[Marco]

The paper said they had a thin film.

Though just using glass for a thin film and magically getting the same properties as the bulk material adds to the unbelievability.

[rteodor]

Just 4 news bellow this one: "Another Retraction Imminent for Controversial Physicist" [...] "who has made controversial claims about discovering room-temperature superconductors".

[AndyBeez]

Scientist makes shocking new discovery that venture capital burns at room temperature.

Now trending on X.

[AndyC_772]

Now trending on X.

Indeed!

https://twitter.com/Rainmaker1973/status/1684218600456876032

[dzseki]

Here are links for the actual paper(s):
https://arxiv.org/ftp/arxiv/papers/2307/2307.12037.pdf

https://arxiv.org/ftp/arxiv/papers/2307/2307.12008.pdf

They do show super conducting property at room temperature indeed, the critical current is around 250mA though.