If I'm reading this right, then the real big benefit of these things would be solid state magnetic storage.
The benefit of these things is they don't create a magnetic field while they do respond to magnetic fields. That means you can pretty tightly pack these things together without concern that they'll interact with each other. A light electric pulse could determine if the bit is a 1 or a zero and a strong pulse would flip the bit.
I'm guessing that due to this nature, these things would actually have pretty long shelf lives and near infinite read/write cycles since you are, effectively, just flipping atoms around and not actually breaking structures or dumping in charge.
These should mostly work with regular silicon manufacturing. The tricky part will be how tightly you can pack these things together before the reading structures start interfering with each other.
That's kind of what the article is talking about. You can do it in a ferromagnetic material (like in your link) but then you've got the problem that it's a magnet and screwing up everything around it.
The idea here is that you can do it in something that is overall neutral.
> these things would actually have pretty long shelf lives and near infinite read/write cycles since you are, effectively, just flipping atoms around and not actually breaking structures or dumping in charge.
Didn't we already play this exact scenario out with 3D XPoint? Is there any expectation that this new type of magnet will be able to compete with flash memory on a unit cost basis?
Actually I guess data retention when unpowered was one year or less but still, is that factor ultimately what led to its discontinuation? I doubt it. For long term data retention you're competing with magnetic tape which has a shelf life measured in decades and an impressively low cost per bit.
3D XPoint wasn't based on magnetic storage and was intentionally targeting a point between NVRAM and DRAM both in terms of price and performance.
BTW, I'm assuming you know but spinning disks are magnetic storage and even today are cheaper than flash memory on a unit cost basis. Generally there's a pretty clear tradeoff you make on all of these primarily around price vs performance (durability tends to be secondary until you get to tape storage).
> Actually I guess data retention when unpowered was one year or less but still, is that factor ultimately what led to its discontinuation?
I am unable to find any actual specific numbers for flash or XPoint. There's just a bunch of unsubstantiated rumors ranging from 3 months, to 1 year, to 5 years, to 10 years. The factors that led to discontinuation is the same as for any product - the market for it never materialized and the cost of continued investment wasn't worth it. Even if it was profitable (not sure), there is always still the opportunity cost of investing that money in a higher ROI venture. Of course, this is Intel who continually failed to sustain long-term payoffs and strategic investments.
> One of Šmejkal’s favourite pieces is Horseman, a striking picture that features an elaborate, tessellating series of mounted figures. Strangely enough, it was this piece that inspired him to predict the existence of an entirely new kind of magnetism.
I find it a little annoying that they don't show the actual artwork (although they do link to a page with it[0]), and give a description that does not really capture what the image conveys. Because upon seeing it, it immediately becomes obvious how that might inspire someone who thinks about electromagnetic fields all day. Well, obvious to people with some passing familiarity with electromagnetic fields at least.
I'm assuming copyright got in the way but even then they could have added an equivalent illustration of their own.
It's a New Scientist diagram, so it's still going to be wrong somehow. We have the quantum "up" and "down", which are not actual directions. The diagram has arrows pointing up or down. Redundantly, every atom with an up arrow is red and every atom with a down arrow is blue. The article also speaks of "enough atoms with magnetic moments pointing in the same direction" to create a strong field, which I think is a literal direction. Then it speaks of "magnetic arrows", presumably a term invented for the article which could mean anything. Then it also speaks of "rotated atoms". Does an atom have a direction? The diagram has oval blobs around the atoms. These rotate alternatingly in the altermagnet. But the arrows don't rotate. So what are the blobs, and what are the arrows?
The article does a decent job eventually of explaining a use-case in the section "Confirming that altermagnets exist".
Seems you can store information at high density in electron spin in materials where spins are naturally organized. However, so far the only suitable materials have been ferromagnets, which have macroscopic magnetic fields that make using them a nightmare. The new altermagnets have suitably organized spins but the atoms alternate their magnetic fields so there is no net magnetism from the material and they are easier to work with.
I did my PhD in this area. It’s very difficult to “read” information stored when there is no net magnetism. Hard drives are built using a read head that detects the stray field from ferromagnetic materials.
When there are particular topological textures like skyrmions you do get a spin hall effect which is quantised but in applying currents you also change the magnetisation through something called spin transfer torque.
> In 2024, researchers led by Atasi Chakraborty, a member of Šmejkal’s research group, demonstrated that applying compressive strain to rhenium dioxide – long known to be an antiferromagnet – triggers a transition into an altermagnetic state.
> What’s more, a trio of researchers at the Beijing Institute of Technology in China realised that you can also create the right internal magnetic disturbances by stacking an antiferromagnet between layers of a different material, like a sandwich.
Does anyone else find it odd that they do not name the authors of the paper[0] that showed the second discovery? (Yichen Liu, Junxi Yu, and Cheng-Cheng Liu, for the record).
Brought to you by the Tax Payers of Czechia, Germany, and the EU via :
* Czech Science Foundation
* The Ministry of Education of the Czech Republic
* European Research Council
* Deutsche Forschungsgemeinschaft (German Research Foundation)
Which raises the question -- Norway famously made its citizen fund using oil money, but which country has made the most for it's citizens from [technology] IP?
Well, ASML is Dutch and started as a spin-off of government-funded research IIRC, but I don't know how big it is in terms of national GDP. On the other hand, the chips their machines enable also represents the kind of wealth not captured in money alone.
"However, researchers tend to feel that these clever tricks may not lead to scalable altermagnets anytime soon, as the methods are difficult to pull off."
This is a good scientific discovery, if replicated, but the hype drowns out the science.
Readit News
https://archive.ph/ObokU
If I'm reading this right, then the real big benefit of these things would be solid state magnetic storage.
The benefit of these things is they don't create a magnetic field while they do respond to magnetic fields. That means you can pretty tightly pack these things together without concern that they'll interact with each other. A light electric pulse could determine if the bit is a 1 or a zero and a strong pulse would flip the bit.
I'm guessing that due to this nature, these things would actually have pretty long shelf lives and near infinite read/write cycles since you are, effectively, just flipping atoms around and not actually breaking structures or dumping in charge.
These should mostly work with regular silicon manufacturing. The tricky part will be how tightly you can pack these things together before the reading structures start interfering with each other.
Feynman moment. Breaking it down into one sentence. Bravo!
Dead Comment
Wouldn't this also enable a much higher resolution and better noise immunity for the entire zoo of industry sensors that are based on the Hall effect?
The idea here is that you can do it in something that is overall neutral.
Didn't we already play this exact scenario out with 3D XPoint? Is there any expectation that this new type of magnet will be able to compete with flash memory on a unit cost basis?
Actually I guess data retention when unpowered was one year or less but still, is that factor ultimately what led to its discontinuation? I doubt it. For long term data retention you're competing with magnetic tape which has a shelf life measured in decades and an impressively low cost per bit.
BTW, I'm assuming you know but spinning disks are magnetic storage and even today are cheaper than flash memory on a unit cost basis. Generally there's a pretty clear tradeoff you make on all of these primarily around price vs performance (durability tends to be secondary until you get to tape storage).
> Actually I guess data retention when unpowered was one year or less but still, is that factor ultimately what led to its discontinuation?
I am unable to find any actual specific numbers for flash or XPoint. There's just a bunch of unsubstantiated rumors ranging from 3 months, to 1 year, to 5 years, to 10 years. The factors that led to discontinuation is the same as for any product - the market for it never materialized and the cost of continued investment wasn't worth it. Even if it was profitable (not sure), there is always still the opportunity cost of investing that money in a higher ROI venture. Of course, this is Intel who continually failed to sustain long-term payoffs and strategic investments.
I find it a little annoying that they don't show the actual artwork (although they do link to a page with it[0]), and give a description that does not really capture what the image conveys. Because upon seeing it, it immediately becomes obvious how that might inspire someone who thinks about electromagnetic fields all day. Well, obvious to people with some passing familiarity with electromagnetic fields at least.
I'm assuming copyright got in the way but even then they could have added an equivalent illustration of their own.
[0] https://escherinhetpaleis.nl/en/about-escher/escher-today/ho...
[1] https://www.nga.gov/artworks/54229-horseman (alternate link in case the first one doesn't load)
Seems you can store information at high density in electron spin in materials where spins are naturally organized. However, so far the only suitable materials have been ferromagnets, which have macroscopic magnetic fields that make using them a nightmare. The new altermagnets have suitably organized spins but the atoms alternate their magnetic fields so there is no net magnetism from the material and they are easier to work with.
When there are particular topological textures like skyrmions you do get a spin hall effect which is quantised but in applying currents you also change the magnetisation through something called spin transfer torque.
> What’s more, a trio of researchers at the Beijing Institute of Technology in China realised that you can also create the right internal magnetic disturbances by stacking an antiferromagnet between layers of a different material, like a sandwich.
Does anyone else find it odd that they do not name the authors of the paper[0] that showed the second discovery? (Yichen Liu, Junxi Yu, and Cheng-Cheng Liu, for the record).
[0] https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.13...
* Czech Science Foundation * The Ministry of Education of the Czech Republic * European Research Council * Deutsche Forschungsgemeinschaft (German Research Foundation)
Natural resources v IP resources?
Post-1950 this is unambiguously the United States.
Dead Comment
This is a good scientific discovery, if replicated, but the hype drowns out the science.