[HN Gopher] Researchers discover new third class of magnetism
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Researchers discover new third class of magnetism
Author : pavel_lishin
Score : 142 points
Date : 2024-12-13 14:52 UTC (3 days ago)
(HTM) web link (www.nottingham.ac.uk)
(TXT) w3m dump (www.nottingham.ac.uk)
| totallykvothe wrote:
| What the heck is antiparallel and why is it different from
| perpendicular?
| bradrn wrote:
| '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: ||)
| getcrunk wrote:
| Parallel without qualification should not imply direction?
| K0balt wrote:
| 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.
| getcrunk wrote:
| Everything you added is context I.e. qualifications
| digging wrote:
| Context is indeed what narrows the meaning of a word with
| various or broad meanings.
| theoreticalmal wrote:
| Maybe the car metaphor breaks down sooner than you'd
| hoped?
| robertlagrant wrote:
| Just like a real car.
| danwills wrote:
| 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.
| PittleyDunkin wrote:
| Parellelism doesn't imply directionism at all.
| gus_massa wrote:
| 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.
| gilleain wrote:
| 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.
| phantomathkg wrote:
| 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.
| PittleyDunkin wrote:
| 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.
| ajkjk wrote:
| It is a very standard term in physics at the
| undergraduate level.
| PittleyDunkin wrote:
| Such definitions may not make sense but it's still worth
| accepting them.
| seanhunter wrote:
| 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.
| Ankaios wrote:
| Here's the Nature article that the university press release links
| to: https://www.nature.com/articles/s41586-024-08234-x
| kergonath wrote:
| Thanks. I'll take that over an over-hyped press release from a
| university PR person.
| hammock wrote:
| 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...
| whatshisface wrote:
| 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).
| Jarmsy wrote:
| It seemed odd to me that the article gave the authors' email
| addresses but no link to the actual article!
| vlovich123 wrote:
| > 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.
| aziaziazi wrote:
| 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.
| grishka wrote:
| 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.
| spwa4 wrote:
| 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.
| kissiel wrote:
| 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.
| spwa4 wrote:
| 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.
| buttercraft wrote:
| > 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.
| teddyh wrote:
| 10 years? Try _three months_ (worst case, but still):
| <https://news.ycombinator.com/item?id=37144598>
| unnah wrote:
| 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.
| mannykannot wrote:
| > 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
| GrantMoyer wrote:
| > 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
| geniium wrote:
| Surprised there are not more comment on this huge news.
|
| Is there another post I missed that is more viral?
| t0lo wrote:
| Welcome to the post science world
| Gigachad wrote:
| 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.
| t0lo wrote:
| 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.
| robertlagrant wrote:
| 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
| ganzuul wrote:
| 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?
| gus_massa wrote:
| 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.
| foven wrote:
| 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.
| gus_massa wrote:
| 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.)
| intalentive wrote:
| I didn't even know there were two classes of magnetism.
| smolder wrote:
| 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.
| piannucci wrote:
| 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.
| foven wrote:
| 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.
| hoseja wrote:
| In the context of the article it's probably ferromagnetism
| and antiferromagnetism though.
| amelius wrote:
| Magnetism __itself__ arguably doesn't even exist, as it's an
| emergent property of relativity and electrostatics.
| lokimedes wrote:
| A new class of magnetism or magnet? Are we adding a new term to
| the equations or another bird to the catalog?
| freehorse wrote:
| Yeah a new class of magnetic materials, not a new class of
| magnetism. Not magnetic monopoles either.
|
| My brain hurts.
| marcosdumay wrote:
| A new kind of solution for some equations that are way too
| complex for us to know all the ways they can go.
| superidiot1932 wrote:
| the spirit of lk-99 lives on
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