Researchers discover new third class of magnetism | Hacker News Reader

Researchers discover new third class of magnetism

nottingham.ac.uk

146 pointspavel_lishin55 comments

Here's the Nature article that the university press release links to: https://www.nature.com/articles/s41586-024-08234-x

Reminds me very much of much of the frontier science Ashton Forbes (the crazy zero-point energy guy) has been exposing on Twitter. For example:

"There is a very deep connection between magnetism and zero-point energy. So yeah, go ahead and build a magnetic motor. It's possible to draw this energy just using spins of electrons and permanent magnets." https://x.com/JustXAshton/status/1830621589848928459

Unfortunately I can't find some of the more relevant posts I have seen recently. But maybe someone else on HN also follows this guy.

Also: Magnet 900,000 times stronger than Earth reveals directional mass particles https://www.yahoo.com/news/magnet-900-000-times-stronger-140...

Just because energy is there doesn't mean you can use it. You can only use changes in energy, like a battery discharging or a log burning. Zero point energy is the resting energy of empty space, and the only theoretical scenarios where it changes involve the laws of physics being changed and the universe being destroyed. In a sense it's the tension of having laws of nature. I sincerely hope it's not on the menu of consumable fuels.

It's also worth mentioning that quasiparticles are bursts of energy that move through materials. For example a soundwave is a burst of quasiparticles, and the quietest possible sound is one quasiparticle, a phonon. I think this disclaimer should accompany all of the press releases about new particles discovered in condensed matter (solids, basically).

It seemed odd to me that the article gave the authors' email addresses but no link to the actual article!

Thanks. I’ll take that over an over-hyped press release from a university PR person.

> They have the potential to lead to a thousand fold increase in speed of microelectronic components and digital memory while being more robust and energy efficient.

Magnets are only used in spinning storage right? And SSDs are typically on the order of 3 orders of magnitude faster if not more in terms of IOPs due to random access performance being roughly the same as sequential. So is this saying 1000x faster than spinning HDDs because of latency or is it saying faster than even flash?

I’m also not too familiar in how magnets show up in microelectronic components in a way that this would speed them up.

> Magnets are only used in spinning storage right?

In the 1970s, magnetic bubble memories were seen as potential replacements for disk drives (and, initially, even semiconductor RAM), but rapid improvements in what we now regard as traditional technology outpaced what could be done with bubble memory.

I am pretty sure that bubble memory is unrelated to the phenomenon discussed here, beyond that it made use of a magnetic effect in a solid substrate.

https://en.wikipedia.org/wiki/Bubble_memory

> Magnets are only used in spinning storage right?

Maybe not forever. Magnetoresistive RAM (MRAM)[1] has the potential to be both faster than DRAM and non-volatile (but maybe not configured for both at the same time), in which case it could replace both DRAM and flash.

That said, I'm not familiar with the physics of MRAM, so I'm not sure the Altermagnets mentioned in the article are applicable to MRAM in particular.

[1]: https://en.wikipedia.org/wiki/Magnetoresistive_RAM

The Nature paper refers to potential applications in spintronics. I'm guessing they mean some kind of improvements to MRAM devices (https://en.wikipedia.org/wiki/Magnetoresistive_RAM), which can be faster than conventional DRAM at the expense of high power usage.

However there's a major issue with SSDs. SSDs keep their data for ~10 years, which is a lot shorter than most people realize. "Spinning rust" will remain operational for longer and should keep the data for at least a century. You cannot have data on SSDs for backup or data hoarding.

I get that spinning rust is put to shame by CD or DVD (even writable ones), but still.

That sounds very optimistic. Do you have any data to back that up? Is it hot or cold storage? I understand, that the breakdown of magnetic field is indeed slow, but the HDD as a whole is not as sturdy, I think - you need to spin the platters, control the heads and so on.

That's true. Perhaps I should say that data on hard drives will remain recoverable, not available, for a century.

Data on CDs/DVDs should remain recoverable for millenia (properly stored, even readable). Another advantage: CDs/DVDs can be duplicated with only analog tools maybe 10 times to further extend that (obviously not writable CD/DVS). And if we were to glue cd's top-to-top, that could be an easy hack to 10x that, which would even work for (re)writable CDs/DVDs.

(Re)writable CDs/DVDs should remain readable/recoverable for centuries too. Probably not millenia.

https://www.easeus.com/resource/does-ssd-need-power.html

TLDR: SSDs keep data for "minimum 1 year" when used as archival storage (of course specific models have been caught losing data in as little as 3 months). Keeping the SSD powered on regularly should increase that, but only to 2-5 years if you want to be on the safe side.

> Data on CDs/DVDs should remain recoverable for millenia (properly stored, even readable).

If by "properly stored" you mean in a cold, dark vacuum, then maybe. Otherwise this is not true in my experience. I've had CD's in temperature controlled storage for 25 years and about 1 on 10 are unreadable. It's my understanding that they oxidize. In theory gold CD'S are immune to that.

10 years? Try three months (worst case, but still): <https://news.ycombinator.com/item?id=37144598>

I also bump on the same sentence about efficiency, just after the one about IT carbon emissions. Doesn’t computation usually use way more power than storage? This looks like journalist trying to oversell it, I hope it’s too lunch skepticism and there’s really something here.

Nonvolatile storage by definition doesn't use any energy to retain data after it's been written. But an HDD needs some to spin either way while it's on, even when it's not currently being accessed. I can kinda see where they're going though — if this discovery enables increased bit density on magnetic media, you need fewer HDDs to store the same amount of data, so they use less energy when they're on.

A new class of magnetism or magnet? Are we adding a new term to the equations or another bird to the catalog?

Yeah a new class of magnetic materials, not a new class of magnetism. Not magnetic monopoles either.

My brain hurts.

A new kind of solution for some equations that are way too complex for us to know all the ways they can go.

I didn’t even know there were two classes of magnetism.

Apparently the two classes are diamagnetism and paramagnetism. Best I can get from reading, diamagnetic materials are more random in their alignment (and repulsed by magnetic fields) and paramagnetic ones are more uniformly aligned (and attracted by fields). Can someone else explain it better?

The article seems to be talking about some new type of ordered alignment. They say anti-parallel, which made me think of overlapping orthogonal alignments, where neighbors are kind of perpendicular, but the image shows vectors which are mostly just slightly off from parallel, creating those swirls.

AIUI, there is a technical criterion for an ambient EM field to imbue circuits within it with broken time-reversal symmetry.

One example of a system that meets the criterion is a ferromagnet. Another is this altermagnet.

One example of a system that doesn’t meet the criterion is a diamagnet. Another is the anti-ferromagnet.

Roughly speaking, some systems are microscopically “asymmetric enough” to be useful in a certain way, and others are “too symmetrical.”

Ferromagnets have a downside that altermagnets avoid: their microscopic fields don’t average out to zero over macroscopic distances.

I think, but honestly don’t really understand, that the goal is to cause the material to treat currents of spin-up and spin-down charge carriers (think electrons or holes) dissimilarly. Constructing materials that distinguish between charge carriers of differing spin is a step towards spintronics. Again, I don’t know why that’s important, but it is what it is.

To add a bit more to this, it's really a new class of magnetism. Traditionally we might think of ordered magnetic materials as being one of two: ferromagnets, which is what you think of when you think of magnets, and antiferromagnets. Antiferromagnets locally order their magnetic moments antiparallel so any which way you measure it, you measure no magnetization.

The application is this: We would like to use ferromagnets and spin currents to make spin-electronic devices ("spintronic") where only the spin information is transferred without any large electrical currents. The goal of this is to save energy from Joule heating as spin can flow with significantly lower energy dissipation.

Ferromagnets run into a lot of problems: they have a stray field, so patterned elements will interact and interfere with each other that sets a limit on how dense each nanostructure can be. Antiferromagnets have a big problem: they are extraordinarily difficult to measure and that is a challenge to overcome.

So the benefit that altermagnetic materials presents is a clear union that tries to overcome the problems of both while retaining the strengths of both.

The exact definition of the ordering of an altermagnet is a bit subtle and it mostly comes from an understanding of how the electronic band structure is different as compared with normal antiferromagnets.

In the context of the article it's probably ferromagnetism and antiferromagnetism though.

Magnetism __itself__ arguably doesn't even exist, as it's an emergent property of relativity and electrostatics.

What the heck is antiparallel and why is it different from perpendicular?

‘Antiparallel’ means parallel but pointing in opposite directions, like so: ↑↓

Whereas ‘perpendicular’ means pointing at right angles: ↑→

(And, of course, ‘parallel’ without qualification would mean pointing in the same direction: ↑↑)

Parallel without qualification should not imply direction?

I think in this case as they are talking about force, it is a vector and implicitly imply direction. So antiparallel really means that the two force are pointing to opposite direction.

You'd think they'd include a term that signaled this is about vectors then! I foolishly assumed this was a new term for "orthogonal", but words don't really need to be meaningfully related to their roots to be meaningful themselves.

It is a very standard term in physics at the undergraduate level.

If you’re talking Euclidian geometry of infinite lines on a plane definitely yes. If you’re talking about vectors then you need an additional concept to capture the way the case of two vectors which fall on lines which in the Euclidian sense are parallel but point in opposite directions is clearly different from two vectors which point in the same direction also. This is like the difference between cars in parallel lanes on one side of a multi-lane highway and the oncoming traffic which would be antiparallel.

Mmmmm I don’t think you would say that two cars going opposite directions on a road , in opposite lanes, are on a parallel path, you would say they were on an opposite path, I would think.

But if those two cars were traveling the same direction, in the same two lanes, they would be properly described as following a parallel path.

from a line vs ray perspective parallel and opposite are equivalent, but when they are rays and not lines, directionality matters.

Maybe the car metaphor breaks down sooner than you’d hoped?

Just like a real car.

Everything you added is context I.e. qualifications

Context is indeed what narrows the meaning of a word with various or broad meanings.

I don't think it does, but rather says whatever direction the first one is pointing in is exactly the same as the direction the second one points in.

Parellelism doesn't imply directionism at all.

From a mathematical point of view: no, no directionism at all.

From a physicist working with spins point of view: yes, parallel has the same direction and antiparallel the oposite.

Each area create their own jargon. Sometimes it's confusing to ousiders and when you pick a book from another area you must double check that the worlds mean what you think their mean.

For what it's worth, protein structural biochemistry uses similar terminology for sheets. Since a strand has a direction (N to C), sheets are 'parallel' when neighbouring strands are pointing (roughly) in the same direction, and 'antiparallel' when pointing in opposite directions.

Such definitions may not make sense but it's still worth accepting them.

the spirit of lk-99 lives on

Surprised there are not more comment on this huge news.

Is there another post I missed that is more viral?

It makes you question what they mean by discovery. Is it not a discovery until it is published in Nature? On Arxiv this was a discovery in 2021. We can probably find a free energy channel in the YouTube haystack from a decade ago where the guy happened to arrange magnets in this order while going through permutations. Is that discovery or are only incumbent academics allowed to canonize science?

This is not really as simple as just going through the permutations. What this is in practice is a triumph of instrumentation. Before this, no one has imaged altermagnetic domain structure. The behaviour of these materials is intrinsically linked to what happens in the micro- (or nano-) structure.

There are two challenging things here that makes this a discovery. One, making the material, which is extremely difficult to verify as altermagnetic due to the nature of measuring these materials. Two, the measurement, which combines two techniques to distinguish this as separate from antiferromagnetism.

It is a huge push forwards for the budding field since it provides a really nice way to go to a large-scale synchrotron with your altermagnet and study it in detail.

Oh, okay I think I understand.

This would have to scale down to the quantum domain to be an actual thing and scaling back up means we bring non-commutative physics into the classical world.

They didn't use macroscopic magnets to form the alternate pattern or the swirls, and they are stable. If you have a link to a YouTube Channel with a similar result, it would be nice to see it.

Also, do you have a link to the arxiv post of 2021? It's a lot of time. This article looks like studing how to "see" the pattern. Perhaps the old one was about the material and general properties.

I was actually thinking of the engineering-minded people who experiment with permanent magnet electric motors out of intuition. The bit about free energy was hyperbole of mine.

From 2021:

https://arxiv.org/abs/2105.05820 This is the numerical discovery.

I'm trying to decide if we are intentionally 'translating' these ideas from pure imagination down into technological applications through intermediate 'realms' of quasi-reality, or if building stuff with just intuition can still be accepted in the 21st century. The BS is just piled too high for me and my trust in technology is not great. Sometimes I wonder if we are just having a mass psychosis in a field of mud.

It looks similar but I'm not sure it's the same.

IIUC the new article is about taking a "photograph" of the magnetiation in a real sample, and the old article is a theoretical prediction. Perhaps the new article should be presented as a confirmation instead of a discovery, but press releas are full of omisions and overhype.

It's probably not groungbreaking. The title is misleading.

It's just a new arrangement of the spins in material. It may be useful to get better transformer or something, like improve them 1%, or in 30 years it may cause a huge unexpected thechnology revolution and my comment would look silly. There are similar discoveries of new materials with weird properties every month. Unless you work in that area, it is probably safe to ignore it for the next 10 years until it has some aplications. (Or you may enjoy reading the technical details.)

Welcome to the post science world

There's definitely fatigue around science news where media orgs massively over inflate or prematurely celebrate. Without actually being in the field yourself it's impossible to tell if any discovery is a nothingburger, 20 years away from meaning anything, or about to change the world. And most of the time it's the first two.

Currently my source of truth is Sabine Hossenfelder, on YouTube. Worth a look.

EDIT: she has a video on this[0] from 9 months ago! There you go.

[0] https://www.youtube.com/watch?v=D0st_6sE7Bk

That's true, but I was more commenting on the loss of science from the public subconscious and our media outside of 7 second tiktok videos that link to current trends.

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