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Stanford, IBM Team To Explore Spintronics
saxylife writes "NYTimes and various other media are carrying a story on the latest venture between IBM and Stanford," which will concentrate on spintronics, in other words, controlling "the magnetic orientation of atoms to store data.
It's supposed to ease the pressure of hitting the barrier of Moore's law."
One final interesing quote from the artice:
"I can not bring myself to believe that if knowledge presents danger, the solution is ignorance" - Isaac Asimov
http://en.wikipedia.org/wiki/Spintronics
you may find the Higgs in this signature.
Apparently a mod doesn't understand the meaning of 'spin' as it relates to news...
No, Moore's Law applies to transistor density. Transistor density depends on the smallest line we can draw on a microchip. Storage media sizes depend on the smallest line we can draw on a platter.
Platter density and transistor density are more closely related than you might think.
For those (like myself) who have little idea about spintronics, Wikipedia has a general article that seemed to explain it to me quite well. Of course, I'm not a physicist so I have no idea whether or not it's accurate although I'm tempted to find out more from the referenced article. PhysicsWeb has more of the same. Apparently this will have far-reaching implications on RAM and cable bandwidth.
Although this may sound similar at the level of description given in the articles, don't let the journalists deep and impressive knowledge of this technology blind you.
The devices that are being talked about work in profoundly different ways to the old ST506 disks. Plus that fact that spintronics has been expanded to cover anyhting with magnets doesn't help clarification much.
For example, despite zdnets claims that IBM use GMR heads in their hard disks - that's not true, they are spin valves. These show a change in elecrical resistance in the prescence of a magnetic field - but no where near the magnitude of effect of a GMR device. That's fundementally different from the older method used in the read heads, which was to have a coil of wire, and detect the current induced in that coil.
If you can align the spin of electrons (do-able), then you can orient the spin, and thus have two independant channels within a single wire (horizontal and vertical, or whatever you want to call them). That's pretty novel.
Electrons carry both charge and spin. They can tunnel.
Spin is a property not a particle, hence your
question makes no sense (even RVB diehards who argue
for spin-charge separation in some materials will
assign spin to some quasiparticle, a "spinon", and
even in those cases tunneling is reserved for
electrons).
Your question is a bit like: "what does blue taste
like?"
but are expensive. Battery backed RAM disks.
The reason such things are expensive (and will likely remain so), is because with no moving parts, you have to have connectors to each bit of storage. That's a lot of interconnects requires, which takes up space, adding to the cost. Once you have a large enough array of bits, the routing of the data and address lines becomes the dominant factor in the construction.
I saw a presentation on spintronics given at WorldCon by Kevin Roche, who is one of the IBM researchers developing this stuff. He will be giving another presentation on it at -- of all places -- BayCon 2004.
I found his talk absolutely fascinating. He's basically created a "transistor" that allows through only electrons of a particular spin. Once you have an electric current composed of electrons spinning all the same way, you can do lots of unexpected things. One example: Light-emitting diodes emit polarized light! Even if you have only a cursory exposure to physics or chemistry, you'd probably enjoy his talk.
Schwab
Editor, A1-AAA AmeriCaptions
Yes, it's still the electrons tunneling across. And it's quite appropriate that you use the word 'barrier'.
There are spin tunnel junctions, where the electron tunnels through an insulator, and people are measuring how long the spin can be preserved if the electron tunnels into a standard metal. Ie, after enough scattering points the spin will be effectively randomized.
But yes, electrons are tunneling, and in some cases the spin of the electron (whether up or down) determines how well it will tunnel through the barrier. So spin is really another parameter that can be controlled to make spin-transistors or spin valves more dynamic than traditional transistors.
make world, not war
But this technology works by altering an attribute of something that's always there, just like traditional magnetic storage.
Bubble memory works not by altering the bubbles, but by creating a pattern of bubbles. In a way it was like punched paper tape.
I'd say that Spin memory is more like acoustic delay lines than bubble mem.
The term "law" should only be applied to true laws, eg. thermodynamics, Newton's and Murphy's.
Umm.. Murphy's law is no more of a "true" law than Moore's is.
Mmmm.. Donuts
Not to be rude or intend to flame or anything, but spintronics has nothing to do with bubble memory. I'm doing a phd in spintronics under an advisor who focuses on magnetism, so i feel qualified in saying this. Bubble memory i don't know much about, other than it uses novel orientations and sizes of domains for magnetic recording.
t ron/index.html
spintronics, on the other hand, uses the charge and spin of electrons and holes in a similar method as electrons and holes are used in standard electronics. for example, the energy required to depopulate a channel in a transistor (turning it on or off) is far greater than the energy required to flip the spins of the charge carriers... so using that, you could have a smaller and lower energy transistor.
the limitation at the moment is in the materials, which is what we do... making them work at and above roomtemp for example.
if you be wanting to see a little more, check out our research page: http://depts.washington.edu/kkgroup/research/spin
to email me: take my
Bubble memory used magnetic domains and depended on electromagnets to move the domains around. The devices were non-volatile and rugged. The largest one made was about 4Mbit, and was the size of a credit card (TI or Intel, I think). Since the usual architecture was a shift register, its closest competitor was disk rather than RAM. They could be completely erased by a strong magnetic field.
MRAM uses spintronics to store data. Its supposed to be very fast (dram speeds), dense, and not too expensive.
;)
Oh did I mention non-volatile ?
This isnt some fancy technology thats going to maybe apear in ten years.
There are preliminary datasheets out now right here.
I cant wait to change my hdd over to this stuff (welll, that may be years away
It's easier to fight for one's principles than to live up to them.
"Moore's law" does not refer to the speed of processors doubling, but that the number of transistors that can be fit into a given area doubling every 18 months or so.
The shrinking of transistor sizes has lead to smaller, cooler, faster, more powerful chips, but the speed increase is just a side effect of the smaller transistors. Were chip engineers more interested in packing more operations each cycle onto a chip, then you would see slower clock speeds with similar densities of transistors on larger areas (with more heat buildup being the speed limiter) -- something akin to the PowerPC chips vs the high-speed Pentiums. Similar densites of transistors and the PPCs actually do more floating-point operations per second (flops) than a Pentium that runs at about twice the clock.
"When ideology and theology couple, their offspring are not always bad but they are always blind." -- Bill Moyers