Scrutable

Posted: **Wed Jul 26, 2023 1:52 pm**

shpalman wrote: ↑
Wed Jul 26, 2023 11:06 am

Brightonian wrote: ↑
Wed Jul 26, 2023 10:23 am

shpalman wrote: ↑
Wed Jul 26, 2023 6:12 am
The First Room-Temperature Ambient-Pressure Superconductor

Of course nobody actually believes it.

room-temperature superconductor (Tc≥400 K, 127°C)
I think even my father would find a room temperature of > 127° a tad high. (Obviously, there's a specialist meaning of room temperature in fizziks.)
What I think they mean is that they went up to 400 K and still hadn't seen the transition out of "superconductivity" which does strongly suggest to me that they're never in superconductivity in the first place.

The plots show the expected decrease in critical current and magnetic field with temperature. Which strongly suggests superconductivity is really there.

Replication of the material is reportedly simple, requiring only basic lab equipment. So we should know if it can be replicated very quickly.

Posted: **Wed Jul 26, 2023 2:01 pm**

Having now fully read the paper and the supplementary materials, I'm extremely cautiously optimistic. There's sufficient detail in the sample preparation and measurement sections to make replication easy, and there's evidence of significant cross-checking with other researchers on aspects of the material measurements.

Basically, this is what a paper describing the discovery of room temperature superconductor should look like.

Posted: **Wed Jul 26, 2023 2:11 pm**

Can anyone summarise for non-physics general science people what and how they've managed to do? And what sort of timescales for verification and excitement?

If it's as reported this seems to be a huge deal for all manner of real world applications?

Posted: **Wed Jul 26, 2023 2:25 pm**

science_fox wrote: ↑
Wed Jul 26, 2023 2:11 pm
Can anyone summarise for non-physics general science people what and how they've managed to do? And what sort of timescales for verification and excitement?

If it's as reported this seems to be a huge deal for all manner of real world applications?

They've produced a material with a chemically induced internal stress, which mimics the effects of the high-pressure applied to some materials that allow them to show superconductivity at higher (but probably not room) temperature.

The material is a lead/phosphorus/oxygen base called lanarkite, with about 1/10th of the lead replaced by copper. Making it is a matter of grinding up the right proportions of lead oxide, lead sulfate together and heating to 725 C in vacuum for 24 hours to make lanarkite, and then grinding that up with copper phosphate (made in a similar way at 525 C and 48 hours), and heating to 925 C in a vacuum for 10 hours.

Replication could be done in less than a week.

They also claim to have made thin film versions of the material, suitable for circuits.

Posted: **Wed Jul 26, 2023 2:45 pm**

I note that they make copper(I) phosphide by mixing copper and phosphorus powder (then baking it under vacuum in a furnace).

Be careful doing that bit.

Posted: **Wed Jul 26, 2023 3:08 pm**

dyqik wrote: ↑
Wed Jul 26, 2023 2:25 pm

science_fox wrote: ↑
Wed Jul 26, 2023 2:11 pm
Can anyone summarise for non-physics general science people what and how they've managed to do? And what sort of timescales for verification and excitement?

If it's as reported this seems to be a huge deal for all manner of real world applications?
They've produced a material with a chemically induced internal stress, which mimics the effects of the high-pressure applied to some materials that allow them to show superconductivity at higher (but probably not room) temperature.

The material is a lead/phosphorus/oxygen base called lanarkite, with about 1/10th of the lead replaced by copper. Making it is a matter of grinding up the right proportions of lead oxide, lead sulfate together and heating to 725 C in vacuum for 24 hours to make lanarkite, and then grinding that up with copper phosphate (made in a similar way at 525 C and 48 hours), and heating to 925 C in a vacuum for 10 hours.

Replication could be done in less than a week.

They also claim to have made thin film versions of the material, suitable for circuits.

Thanks! That's a very useful summary.

Posted: **Wed Jul 26, 2023 3:11 pm**

shpalman wrote: ↑
Wed Jul 26, 2023 2:45 pm
I note that they make copper(I) phosphide by mixing copper and phosphorus powder (then baking it under vacuum in a furnace).

Be careful doing that bit.

Yeah, sorry copper phosphide rather than phosphate.

Posted: **Wed Jul 26, 2023 3:12 pm**

Slightly surprised by the (implied) hand grinding up of material in an agate mortar with a pestle - I would have expected a more standardisable method (e.g. planetary ball mill) as there could be possibly variation in mixing prior to heating.

Posted: **Wed Jul 26, 2023 4:07 pm**

Meanwhile, a second paper by Dias retracted.

Posted: **Wed Jul 26, 2023 4:07 pm**

There's also https://arxiv.org/abs/2307.12037

Posted: **Wed Jul 26, 2023 4:24 pm**

shpalman wrote: ↑
Wed Jul 26, 2023 4:07 pm
There's also https://arxiv.org/abs/2307.12037

Does anyone have the video of levitation?

Posted: **Wed Jul 26, 2023 4:27 pm**

I'm moving from extremely cautious optimism to cautious optimism at the moment.

Posted: **Wed Jul 26, 2023 4:55 pm**

Here the video - https://sciencecast.org/casts/suc384jly50n

Posted: **Wed Jul 26, 2023 6:25 pm**

I like the prodding with a whiteboard marker.

Posted: **Wed Jul 26, 2023 7:16 pm**

FlammableFlower wrote: ↑
Wed Jul 26, 2023 6:25 pm
I like the prodding with a whiteboard marker.

If you wanted to demonstrate "desktop" superconductivity, then it's a good look.

Not as good as a 1970s Open University professor with a kipper tie poking it with a propelling pencil or a pipe stem though.

Posted: **Wed Jul 26, 2023 10:03 pm**

I feel like this could be a holy sh.t moment, but I have seen too many false dawns. If it’s replicated then this could be amazing. I’m just imagining wind turbines with superconducting generators, and I could go on but I will rein in my desire to be pleased.

Posted: **Thu Jul 27, 2023 9:41 am**

Live tweeting X-ing an attempted replication .

eta: Not an established lab though, so I’m not sure if they know what they’re doing or not.

Posted: **Thu Jul 27, 2023 9:57 am**

nekomatic wrote: ↑
Thu Jul 27, 2023 9:41 am
Live tweeting X-ing an attempted replication .

eta: Not an established lab though, so I’m not sure if they know what they’re doing or not.

I'm guessing not so much but probably something. They're a startup building rockets and spacecraft to manufacture stuff in zero-g.

Posted: **Fri Jul 28, 2023 11:12 am**

Das Sarma is not convinced that the authors know any theory of superconductivity https://twitter.com/condensed_the/statu ... 6Ln7A&s=19

Posted: **Fri Jul 28, 2023 11:28 am**

shpalman wrote: ↑
Fri Jul 28, 2023 11:12 am
Das Sarma is not convinced that the authors know any theory of superconductivity https://twitter.com/condensed_the/statu ... 6Ln7A&s=19

Although it should be said that the theory of HTS is fairly esoteric, and doesn't usually get that involved in the practice of making and testing HTS. Their theoretical explanation could way off and they could still have found something extremely interesting.

Posted: **Fri Jul 28, 2023 1:19 pm**

It could be, for example, they've found a material that exhibits superconducting bulk properties via a different mechanism than 3d BCS.

FAPP, that's a superconductor as far as energy and magnet applications go. It may not be for the kind of things they I use superconductors for - tunnel junctions, transition edge devices and Josephson junctions. These rely on the superconducting band gap generated in BCS theory. No one has made a good standard high temperature superconductor version of those devices either.

Posted: **Fri Jul 28, 2023 5:22 pm**

There's a timeline here which I don't know how reliable it is, but it suggests they've been chasing this material for a long time based on some theoretical prediction?

ETA changed the link

Posted: **Sat Jul 29, 2023 7:22 am**

shpalman wrote: ↑
Wed Jul 26, 2023 4:07 pm
There's also https://arxiv.org/abs/2307.12037

It seems like this is the proper paper and the other one will be retracted.

https://twitter.com/8teAPi/status/16849 ... 5MhBQ&s=19

Posted: **Sat Jul 29, 2023 11:45 am**

This is a useful tweet if it's accurate:

https://twitter.com/8teAPi/status/16845 ... NAY9Q&s=19

Posted: **Sat Jul 29, 2023 11:48 am**

All of this makes me more certain that there's something interesting there, but I don't know if it's a BCS superconductor yet.

Scrutable

Superconductivity fight

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