Superconductor room temp ambient pressure

[Carborendum]

1 hour ago, Vort said:

One consumer product area where room-temperature (or higher) superconductors might be game-changing would be permanent or semipermanent supermagnets. But with the advent of neodymium magnets, this niche has already been filled to some degree.

How would superconductors create permanent supermagnets?  I'm not familiar with this phenomenon.

[Vort]

17 minutes ago, Carborendum said:

How would superconductors create permanent supermagnets?  I'm not familiar with this phenomenon.

1. Bring the intended room-temp superconductor magnet above its T_c (the temperature at which it exhibits superconductivity).

2. Expose the intended magnet to a strong magnetic field.

3. While it is in the magnetic field, cool the magnet below its T_c.

Vye-oh-lee! New permanent room-temp superconductor magnet, as long as you don't heat it to above its T_c (which will brick it).

[Vort]

AKA Lenz's Law

[Carborendum]

45 minutes ago, Vort said:

AKA Lenz's Law

I'm familiar with Lenz's Law.  But that only applies when a current is running.  A "permanent" magnet would not require an electric current to be flowing.

If I'm understanding what you wrote, the procedure you outlined would create a permanent magnet, to be sure.  But once the current is off, the remaining magnetism of the permanent magnet is limited based on the inherent magnetic capacity of the magnetic material regions themselves. 

With a superconducting loop, the induced magnetic field would force them to line up nearly 100% in the same direction.  But once the current is off, no induced field.  Thus, the innate properties of the magnetic material would be the determining factor.

Maybe I'm stuck on the term "supermagnet".  I haven't actually seen that term used.  I had assumed that it meant the magnet maintained a magnetic field (permanently) which was comparable only to powerful electromagnets.  Does that mean something else?

 

Edited August 3, 2023 by Carborendum

[Vort]

4 minutes ago, Carborendum said:

I'm familiar with Lenz's Law.  But that only applies when a current is running.  A "permanent" magnet would not require an electric current to be flowing.

If I'm understanding what you wrote, the procedure you outlined would create a permanent magnet, to be sure.  But once the current is off, the remaining magnetism of the permanent magnet is limited based on the inherent magnetic capacity of the magnetic material regions themselves. 

With a superconducting loop, the induced magnetic field would force them to line up nearly 100% in the same direction.  But once the current is off, no induced field.  Thus, the innate properties of the magnetic material would be the determining factor.

Maybe I'm stuck on the term "supermagnet".  I haven't actually seen that term used.  I had assumed that it meant the magnet maintained a magnetic field (permanently) which was comparable only to powerful electromagnets.  Does that mean something else?

This is exactly how e.g. modern MRI machines work. The superconductor that makes up the "tunnel" is established in the presence of a 1- or 2-tesla field. Then when the electromagnet creating the field is removed, the MRI is, in effect, a permanent magnet, assuming it doesn't get quenched. So you do this, but just on a much less expensive scale (no cryogenic refrigeration units).

[Carborendum]

7 minutes ago, Vort said:

This is exactly how e.g. modern MRI machines work. The superconductor that makes up the "tunnel" is established in the presence of a 1- or 2-tesla field. Then when the electromagnet creating the field is removed, the MRI is, in effect, a permanent magnet, assuming it doesn't get quenched. So you do this, but just on a much less expensive scale (no cryogenic refrigeration units).

So, could you explain what is meant by "supermagnet"?

[Vort]

Just now, Carborendum said:

So, could you explain what is meant by "supermagnet"?

Just a word I made up meaning a really strong magnet, much stronger than what we used to play with as children.

[Carborendum]

34 minutes ago, Vort said:

Just a word I made up meaning a really strong magnet, much stronger than what we used to play with as children.

Yes, I'm aware of the creation of magnets using induced magnetic fields.  I don't see how superconductors make any material "more" magnetic than common conducting materials.  Please explain.

[Vort]

48 minutes ago, Carborendum said:

Yes, I'm aware of the creation of magnets using induced magnetic fields.  I don't see how superconductors make any material "more" magnetic than common conducting materials.  Please explain.

You can't make a Lenz's Law magnet without superconductive material.

[Carborendum]

5 minutes ago, Vort said:

You can't make a Lenz's Law magnet without superconductive material.

Why can't you just increase the magnetic field by cranking up the current or number of coils?  Numbers too high?

[Vort]

7 minutes ago, Carborendum said:

Why can't you just increase the magnetic field by cranking up the current or number of coils?  Numbers too high?

We're having a definite communication disconnect. Here's my imagined conversation about the magnets I described:

Alan: I sure wish we could make a really strong magnet, not just these pathetic, wimpy ferrite magnets.

Betty: How about neodymium?

A: Well, sure, they're great. But what I REALLY want is a magnet that doesn't use ferrite domain lineups or the anisotropic properties of rare earths. I want a magnet that just, I don't know, magnets. Like an electromagnet, but it doesn't require a current input. I want to use it to put my daughter's 50-page report on 20th-Century Art and Poetry on the fridge.

B: Sounds like you want a magnet that has an internal, permanent circular current inducing that magnetic field.

A: Yes! Perfect! Except...the current would die away in milliseconds or less. Internal resistance, you know.

B: What if...we used a superconductor?

A: Brilliant! Except that we'd have to cool the magnet down to cryogenic temperatures to get it to work. I want a superstrong refrigerator magnet, something I could use even in boiling water without it losing its magnetic properties, not something that I have to put in liquid nitrogen to use.

B: Oh, that's easy. All we have to do is to make a room-temperature superconductor. We could then take advantage of Lenz's Law to cause an induced circular current that produces a nice, strong, permanent magnetic field.

A: And where would you get this "saved money", uh, "room-temperature superconductor"?

That's what I was working from.

(For those who didn't get the reference.)

[Carborendum]

16 minutes ago, Vort said:

B: Sounds like you want a magnet that has an internal, permanent circular current inducing that magnetic field.

This is what I was missing.  That is a bit outside the box and a few steps outside my area of expertise.

But it would seem like this would violate the first and/or second laws of thermodynamics.  Were you joking?

I don't think that's how MRI machines work.

Edited August 3, 2023 by Carborendum

[Vort]

11 minutes ago, Carborendum said:

This is what I was missing.  That is a bit outside the box and a few steps outside my area of expertise.

But it would seem like this would violate the first and/or second laws of thermodynamics.  Were you joking?

Nope. I'm not an authority, but the whole idea of superconductors, and the reason they seem to be magical, is that there is no resistance to electrical current. Not "very, very low", but literally "zero". So you can do magical things like establish a permanent magnetic-field-inducing current in a superconductor.

13 minutes ago, Carborendum said:

I don't think that's how MRI machines work.

Again, I'm not an authority, but my understanding is that that is exactly how MRIs work. (Well, there's a lot more to it than that, of course, but the basis of MRI is a very strong, constant magnetic field that lines up the hydrogen dipoles so that an RF burst can flip them and then the "receiving coil" can measure their recovery. But you have to start with the strong, constant magnetic field.)

[mikbone]

When the radiofrequency source is switched off the magnetic vector returns to its resting state, and this causes a signal (also a radio wave) to be emitted. It is this signal which is used to create the MR images. Receiver coils are used around the body part in question to act as aerials to improve the detection of the emitted signal. The intensity of the received signal is then plotted on a grey scale and cross sectional images are built up.

Multiple transmitted radiofrequency pulses can be used in sequence to emphasise particular tissues or abnormalities. A different emphasis occurs because different tissues relax at different rates when the transmitted radiofrequency pulse is switched off. The time taken for the protons to fully relax is measured in two ways. The first is the time taken for the magnetic vector to return to its resting state and the second is the time needed for the axial spin to return to its resting state. The first is called T1 relaxation, the second is called T2 relaxation.

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1121941/

Edited August 3, 2023 by mikbone

[Carborendum]

22 minutes ago, Vort said:

Nope. I'm not an authority, but the whole idea of superconductors, and the reason they seem to be magical, is that there is no resistance to electrical current. Not "very, very low", but literally "zero". So you can do magical things like establish a permanent magnetic-field-inducing current in a superconductor.

The magic is that we tend to think of "moving" as "force". Instead, if we look at it in terms of velocity vs acceleration, then it makes a lot more sense.  However, when an electron continues to move in a circle, it is in continual acceleration.  That's the part I don't get.  Maybe there is still some conservation of energy because the forces continually trade back and forth like planets orbiting a star.

[Vort]

9 hours ago, Carborendum said:

However, when an electron continues to move in a circle, it is in continual acceleration.

Excellent point. This was recognized back in the 1920s or 1930s, when Bohr freely admitted that his "planetary model" of the atom couldn't be literally true because the "orbiting" electron would radiate away its energy immediately. That problem was solved by the introduction of quantum mechanics to explain electron states using "cloud" probabilities called orbitals. I expect a similar thing is going on here, where these strange effects are explained through QM hand-waving, though we would probably need to ask a real physicist to find out.

[Vort]

According to ChatGPT:

The behavior of charge carriers in a superconductor is governed by quantum mechanics, where electrons form Cooper pairs and behave collectively rather than individually. As a result, the traditional classical concepts of charged particles radiating energy when accelerated do not apply in the same way within a superconductor.

In other words, "It's magic."

[Carborendum]

On 8/4/2023 at 1:59 AM, Vort said:

According to ChatGPT:

The behavior of charge carriers in a superconductor is governed by quantum mechanics, where electrons form Cooper pairs and behave collectively rather than individually. As a result, the traditional classical concepts of charged particles radiating energy when accelerated do not apply in the same way within a superconductor.

In other words, "It's magic."

Remember that "magic" is really just something we don't understand yet.  But by observation, we tend to construct our best explanation to describe the what, even if we don't know the how/why.  It's called a "scientific model."

Edited August 10, 2023 by Carborendum

[mikbone]

Yeah, I’ve done a little surface lvl study of quantum mechanics.  

Magic

[mikbone]

[Vort]

6 hours ago, mikbone said:

The Chinese said it, so it must be true.

That will go right up there with, "No one that speaks German could be an evil man."

[mikbone]

A result replicated on US soil.  Something is going on here.  From what I gather the manufacturer process is not well described in the paper.  Lots of variables and some of the components are rare.

Still very hopeful.

 

https://tracking.tldrnewsletter.com/CL0/https:%2F%2Fwww.tomshardware.com%2Fnews%2Fengineer-details-messy-lk-99-superconductor-fabrication-process%3Futm_source=tldrnewsletter/1/01000189cf899ce7-d26a38eb-a98a-4733-b3e1-9236d6afd9f8-000000/506fbTuxvkLkSWa359rb9E_6XCDIBAWIzOQydGVGPMw=312

 

Edited August 7, 2023 by mikbone

[mikbone]

https://arxiv.org/abs/2308.03110

Bummer

Edited August 8, 2023 by mikbone

[Traveler]

On 8/3/2023 at 2:24 PM, mikbone said:

When the radiofrequency source is switched off the magnetic vector returns to its resting state, and this causes a signal (also a radio wave) to be emitted. It is this signal which is used to create the MR images. Receiver coils are used around the body part in question to act as aerials to improve the detection of the emitted signal. The intensity of the received signal is then plotted on a grey scale and cross sectional images are built up.

Multiple transmitted radiofrequency pulses can be used in sequence to emphasise particular tissues or abnormalities. A different emphasis occurs because different tissues relax at different rates when the transmitted radiofrequency pulse is switched off. The time taken for the protons to fully relax is measured in two ways. The first is the time taken for the magnetic vector to return to its resting state and the second is the time needed for the axial spin to return to its resting state. The first is called T1 relaxation, the second is called T2 relaxation.

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1121941/

When I was working with the Defense Department and utilizing Josephson junctions to detect small magnetic variations to find various “things” via satellite, I read an article that cancer tissue has slightly different resistance to small electrical currents.  I theorized that with existing technology a human body could be scanned for cancer cells – then by utilizing a circular array of extreme ultraviolet (or x-ray) lasers that focus on the discovered cancer cells that it may be possible to destroy cancer cell by cell leaving normal tissue intact.

 

The Traveler

[Vort]

On 8/8/2023 at 6:48 AM, mikbone said:

https://arxiv.org/abs/2308.03110

Bummer

Don't get too bummed out. In such cases, the "science" involves trying different recipes to find one that hits all the magic buttons. We do not have a deep understanding or a robust model for high-temperature superconductivity. It certainly involved Cooper pairs, like regular low-temp superconductivity, but the way the atomic lattice interacts with the electron Cooper pairs in resonance is not (to my knowledge) well characterized. The first ten thousand recipes might not work, but just wait until 10,001 comes along.