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"Spin Battery" Effect Discovered

kdawson posted more than 5 years ago | from the usual-caveats-apply dept.

Power 234

An anonymous reader writes "Researchers at the University of Miami and at the Universities of Tokyo and Tohoku, in Japan, have discovered a spin battery effect: the ability to store energy into the magnetic spin of a material and to later extract that energy as electricity, without a chemical reaction. The researchers have built an actual device to demonstrate the effect that has a diameter about that of a human hair. This is a potentially game-changing discovery that could affect battery and other technologies. Quoting: Although the actual device... cannot even light up an LED..., the energy that might be stored in this way could potentially run a car for miles. The possibilities are endless, Barnes said.'"

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234 comments

GNAA (-1, Troll)

Anonymous Coward | more than 5 years ago | (#27180973)

Are you GAY? Are you a NIGGER? Join the Gay Nigger Association of America today!

Good (-1, Troll)

Anonymous Coward | more than 5 years ago | (#27181043)

I'm glad. However, I prefer to not see women using implants to increase their breasts that not only look funny, they are funny!

Cool. (5, Funny)

B5_geek (638928) | more than 5 years ago | (#27181103)

This sounds cool, but what they are not telling you is that it will stop working if you bring it south of the equator. :)

Re:Cool. (4, Funny)

Anonymous Coward | more than 5 years ago | (#27181121)

Yes, but on the other hand, it provides limitless energy in Washington DC!

Re:Cool. (0)

Anonymous Coward | more than 5 years ago | (#27182567)

Is there some energy source that does not provide limitless energy in Washinton DC ?

I propose a solution to our economic troubles : have all stimulus money delivered by cars running on our 1950's "just 50 years away" fusion power.

Re:Cool. (2, Funny)

winterphoenix (1246434) | more than 5 years ago | (#27181225)

No, no. It'll work, it will just happen in reverse. We can charge these up like capacitors and steal power from those damn Aussies!

Re:Cool. (2, Funny)

eric2hill (33085) | more than 5 years ago | (#27181261)

No, you just have to take the battery out and flip it around. The poles reverse south of the equator.

Why An LED... (3, Insightful)

LEX LETHAL (859141) | more than 5 years ago | (#27181629)

At least for the proof of concept stage, they might want to make a light source that consumes significantly less juice than an LED, and has a greater tolerance for fluctuation.

From Wikipedia:

"LEDs must be supplied with the voltage above the threshold and a current below the rating. This can involve series resistors or current-regulated power supplies." http://en.wikipedia.org/wiki/Led#Disadvantages [wikipedia.org]

Using an LED as an example of what this tiny power souce can't power seems futile at this point.

news: SI units: the human hair diameter.. (2, Funny)

Anonymous Coward | more than 5 years ago | (#27181829)

I for one welcome the new SI unit human hair diameter overlord.

Re:news: SI units: the human hair diameter.. (0)

Anonymous Coward | more than 5 years ago | (#27182053)

Change Diameter to Frontier and you have yourself an entire new series of Star Trek, in miniature.

Re:Cool. (1)

Nethemas the Great (909900) | more than 5 years ago | (#27182543)

This sounds cool, but what they are not telling you is that it will stop working if you bring it south of the equator. :)

It doesn't stop per-se, it just reverses polarity.

Can't light an LED (4, Interesting)

Taibhsear (1286214) | more than 5 years ago | (#27181109)

Is this due to the scale of the device/experiment or is it a limitation in the output that they can get it to generate so far?

Re:Can't light an LED (4, Interesting)

Anonymous Coward | more than 5 years ago | (#27181167)

Well the device they've built has the diameter of a human hair it doesn't really matter (unless it's also really really long). Ten thousand in a battery the size of a AA would surely give off more energy than existing alkali or NiMH batteries of the same size.

Re:Can't light an LED (3, Insightful)

MobyDisk (75490) | more than 5 years ago | (#27182597)

surely?

How can you be sure when they didn't post anything about the energy density? (Maybe there is some info in the original article, but I don't have access to the journal.

Re:Can't light an LED (4, Interesting)

BillOfThePecosKind (1140837) | more than 5 years ago | (#27181283)

I would think it would be a limitation of the test size. If it's like any other electrical device, we should be able to stack a WHOLE bunch of them in series to create larger voltages. I really hope this goes somewhere, a lot of what is holding us back from implementing more renewable energy sources is the fact that we have no efficient (cost efficient mostly) way of storing the energy.

Re:Can't light an LED (1, Interesting)

poetmatt (793785) | more than 5 years ago | (#27181485)

Well, it's potentially far more efficient than other current methods but how far is to be determined. Magnetic charges do not tend to hold forever, and are limited by certain mechanical aspects that can make it more difficult to harness long term too.

However, both of those are just small engineering issues and should be things that can be resolved through working out the magnetics.

Re:Can't light an LED (4, Interesting)

Chyeld (713439) | more than 5 years ago | (#27181615)

More importantly, you can stack several chemical batteries together for more power and the only issue you have to worry about is heat.

Stack several magnetic based batteries together, are you going to have to worry about their fields interfering with each other? What if this is only a workable model when the battery IS the width of a human hair.

Re:Can't light an LED (1)

GooberToo (74388) | more than 5 years ago | (#27181991)

I wonder if wind turbines might be able to use this method to store "over charges produced from gusts which can then be feed into the grid when the wind drops off. In other words, simply use it as a capacitor for off-peak wind capacity.

Re:Can't light an LED (1, Funny)

Anonymous Coward | more than 5 years ago | (#27182367)

I wonder if wind turbines might be able to use this method to store "over charges produced from gusts which can then be feed into the grid when the wind drops off. In other words, simply use it as a capacitor for off-peak wind capacity.

Say, you're right! We should come up with a word for this..."battery" sounds just awesome! Just like in the summary!

learn to moderate correctly (-1, Offtopic)

SethJohnson (112166) | more than 5 years ago | (#27182091)



Here's a hint:

An off-the-cuff question like this is not 'Insightful'.

Is this due to the scale of the device/experiment or is it a limitation in the output that they can get it to generate so far?

Moderator Support

Miles? (5, Funny)

noundi (1044080) | more than 5 years ago | (#27181155)

...the energy that might be stored in this way could potentially run a car for miles. The possibilities are endless, Barnes said.

Awesome, I have yet to travel miles by car.

Re:Miles? (5, Insightful)

quickOnTheUptake (1450889) | more than 5 years ago | (#27181493)

Although the actual device... cannot even light up an LED..., the energy that might be stored in this way could potentially run a car for miles.

This is one of the least informative lines ever included in a tech summary.
Any energy storing tech that's worth it's salt can potentially run a car for miles. It's a question of efficiency and cost. I can potentially power a car for miles with twisted up rubberbands if I want to, but that isn't a breakthrough in the field.
And of course "miles" tells nothing. Powering a car 3-5 miles is next to worthless. If they said 10's of miles we would know this had the potential to replace current tech or at least come close. If they said 100's of miles we would be facing a revolutionary improvement.

Re:Miles? (5, Funny)

MightyYar (622222) | more than 5 years ago | (#27181969)

I can potentially power a car for miles with twisted up rubberbands if I want to

I think there is some stimulus money available for you.

Re:Miles? (0)

Anonymous Coward | more than 5 years ago | (#27182039)

I think what they meant is that a battery the size of a hair could run a car for miles.

Since any new technology must compete with the range, weight and volume of the current combustion engine + fuel tank + drive train solution, a strand of hairs + 4 electric motors in the wheels + a few cables don't sound too bad.

Re:Miles? (1)

Surt (22457) | more than 5 years ago | (#27182439)

If you can run a car miles on twisted up rubber bands, that is a breakthrough. Current twisted rubber band technology is weight bound, and can't run a real car more than about a quarter mile within the volume legally allowed for passenger cars in the US.

yeah, if you believe the spin... (4, Funny)

140Mandak262Jamuna (970587) | more than 5 years ago | (#27181159)

Oh, yeah. We know how the spin works. But it works only in the PR side of things.

Re:yeah, if you believe the spin... (2, Funny)

Anonymous Coward | more than 5 years ago | (#27181437)

I think this actually solves the ancient gnome riddle:
1. Create tiny stackable PR agent.
2. Release photo of it's employer doing coke of a hookers ass.
3. Harvest spin energy.
4. Profit!

Re:yeah, if you believe the spin... (2, Funny)

Anonymous Coward | more than 5 years ago | (#27182037)

2. Release photo of it's employer doing coke of a hookers ass.

Hey jerry, get back to work. Also, I told you to get rid of that picture.

Re:yeah, if you believe the spin... (1)

JosKarith (757063) | more than 5 years ago | (#27182333)

Energy from spin... maybe we've found a use for our surfeit of politicians after all...

Achem (4, Insightful)

girlintraining (1395911) | more than 5 years ago | (#27181163)

In THIS house, we obey the laws of thermodynamics. So you create a magnetic field, okay. Great. What's to prevent everything that's metallic in the area from moving around it, inducing current in it, and converting it into useless thermal energy? In other words -- what's preventing the battery from discharging? It might be good for a really high-capacity capacitor, but a battery? Batteries are long term.

Re:Achem (1)

ChromaticDragon (1034458) | more than 5 years ago | (#27181253)

Magnetic shielding?

A Faraday cage?

Re:Achem (4, Informative)

Hordeking (1237940) | more than 5 years ago | (#27181355)

Magnetic shielding?

A Faraday cage?

Faraday cages don't stop magnetic fields.

Even if you do stop the magnetic field (it can be done, but not with a Faraday cage), your battery would be inducing regular and eddy currents in the shield, which will convert the magnetic field to useless thermal energy over time.

Re:Achem (4, Funny)

CecilPL (1258010) | more than 5 years ago | (#27181727)

Now Eddy's in currents too? I think I saw his couch float by back when he was in the space-time continuum.

Re:Achem (1)

Hordeking (1237940) | more than 5 years ago | (#27181833)

Now Eddy's in currents too? I think I saw his couch float by back when he was in the space-time continuum.

I knew that Eddy kid was no good when he said he didn't like his teddy.

Re:Achem (0)

Anonymous Coward | more than 5 years ago | (#27181783)

But what's Eddy doing inside the battery?

Re:Achem (3, Insightful)

LordKronos (470910) | more than 5 years ago | (#27181797)

Yeah, but what sort of time scale are we talking about? Even current batteries discharge themselves over time.

Re:Achem (2, Interesting)

davolfman (1245316) | more than 5 years ago | (#27182109)

Mu metal?

Re:Achem (1)

Hordeking (1237940) | more than 5 years ago | (#27182475)

Mu metal?

That's the stuff. Of course, I suspect it works similarly to an electrostatic metal shell. An outside magnetic field induces a magnetic flux in the mu-metal shell, attenuating the field inside. Of course, this is likely to generate heat as the magnetic field tries to perform work on the shell.

I could be wrong. I didn't really study magnetism very much.

Re:Achem (5, Insightful)

Anonymous Coward | more than 5 years ago | (#27181497)

Yeah you're right. I bet they totally never thought of that.

When did "In THIS house, we obey the laws of thermodynamics" turn into some goddamn meme that gets pulled out when what you really mean is "I don't understand, can anyone please explain?"

Because you're implying that these researchers are in some other house that doesn't obey the laws of physics, and that pointing this out is some revelation. Physicists from three institutions in two countries worked on this - are you really so stupid to think they don't know about thermodynamics? Really?

Re:Achem (1)

Chyeld (713439) | more than 5 years ago | (#27181701)

Regardless of whether the researchers understand what is going on, the question is whether the project itself is being presented with that understanding. It wouldn't be the first or last time a researcher presented what were ulitmately "useless in the real world" findings with the full internal knowledge that they would prove as such, simply to secure more grant money.

Nor would it be the first or last time a wild eyed science journalist took a small breakthrough and extrapolated men on mars with jetpacks from it.

Looking at things with a critical eye can help you know.

Re:Achem (1, Insightful)

Anonymous Coward | more than 5 years ago | (#27182581)

That wasn't what the post said.

The post didn't say "I wonder if they've taken X into account" or "They don't address the problem of Y" or "I wonder how this will fare in the real world"

It doesn't even say "I'm a bit skeptical of this, as it seems to break thermodynamic laws".

If they'd started the post with "I'm intrigued by the thermodynamics of this", I'd be sympathetic. What they said was a glib statement to the effect of "[The researchers] are not obeying thermodynamics". Thats a staggering assertion to make.

Re:Achem (4, Informative)

Comboman (895500) | more than 5 years ago | (#27182025)

When did "In THIS house, we obey the laws of thermodynamics" turn into some goddamn meme

Simpsons season 6, episode 21 ("The PTA Disbands").

Re:Achem (4, Funny)

Rogerborg (306625) | more than 5 years ago | (#27181619)

In other words -- what's preventing the battery from discharging?

A liberal coating of snake oil.

If you actually RTFA.. (0)

Anonymous Coward | more than 5 years ago | (#27181185)

You will see that the main use of this is to replace moving parts in computers (and apparently can act as a replacement for the transistor).

Pretty interesting stuff but I would wait for an actual tech demo, it all seems pretty pie in the sky right now.

Re:If you actually RTFA.. (1)

Hordeking (1237940) | more than 5 years ago | (#27181371)

You will see that the main use of this is to replace moving parts in computers (and apparently can act as a replacement for the transistor).

Pretty interesting stuff but I would wait for an actual tech demo, it all seems pretty pie in the sky right now.

I took from the article that the main use for this would be to replace chemical reactions in batteries.

Re:If you actually RTFA.. (2, Informative)

Gat0r30y (957941) | more than 5 years ago | (#27182115)

moving parts in computers (and apparently can act as a replacement for the transistor).

I don't think this is a replacement for the transistor, there certainly wasn't any indication that these can perform any logic operations. A replacement for your hard drive, which besides the fan (which you will probably still need), is the moving parts of your computer. It remains to be seen whether this process could be useful at scale. You need billions of these little things, along with some method for reading and writing to each unit. The HDD industry has been working for years (still in R&D phase) on spintronics to store data, and there is still a long way to go. But there is indeed great promise in it as well.

Isn't there already energy in the spin (1, Interesting)

Anonymous Coward | more than 5 years ago | (#27181193)

Can't we just extract it without having to put some in first?

Re:Isn't there already energy in the spin (1)

OolimPhon (1120895) | more than 5 years ago | (#27182035)

Can't we just extract it without having to put some in first?

Sure, if you want to end up living on a neutron star.

not what I thought (0)

paperdiesel (809538) | more than 5 years ago | (#27181199)

Did anyone else think that this was going to be a scientific explanation about why your batteries last a bit longer when you take them out and rotate them and put them back in?

Cue dildo jokes in 3... 2... 1...

Breakthrough! (1)

nloop (665733) | more than 5 years ago | (#27181245)

from the article: "The new technology is a step towards the creation of computer hard drives with no moving parts"

Maybe we could give it a cool 3 letter acronym. Maybe SSD, Solid State Drive, yeah! This could revolutionize things!

Yes, I know I'm taking it out of context, but that was really poorly written.

Re:Breakthrough! (1, Funny)

Anonymous Coward | more than 5 years ago | (#27181327)

Personally I want a SG1 joke

'how does it work?'
-techno bable-
'so magnets'

KERS (0)

rossdee (243626) | more than 5 years ago | (#27181269)

I think they invented the flywheel already.

Anyway it will be interesting to see how KERS plays out this coming season. With the amount of money spent on research in Formula one they are bound to come up with some innovative but expensive technology for storing energy.

Re:KERS (1)

nloop (665733) | more than 5 years ago | (#27181357)

This wasn't a flywheel and isn't kinetic energy.

Magnetic.

I guess maybe you could say it's billions of electron's functioning as flywheels, but still, no.

CAUTION (5, Funny)

Waffle Iron (339739) | more than 5 years ago | (#27181315)

Do not open or crush battery. Severe risk of releasing a life-sucking vortex.

Do not dispose in fire. Doing so could loose a storm of flaming vortices.

Do not use this battery on carnival rides, while figure skating, or place in spinning clothes washer. Risk of severe gyroscopic reactions, which may lead to property damage, personal injury or death.

Re:CAUTION (1, Funny)

CaptainPatent (1087643) | more than 5 years ago | (#27181561)

Warning:

Do not open or crush battery. Severe risk of releasing a life-sucking vortex.

Do not post on Slashdot after watching vampire movies. Severe risk of relating every story to sucking life force out of humans.

Do not dispose in fire. Doing so could loose a storm of flaming vortices.

Do not post on Slashdot after playing too many video games. Severe risk of hallucinating amazing 3d effects.

Do not use this battery on carnival rides, while figure skating, or place in spinning clothes washer. Risk of severe gyroscopic reactions, which may lead to property damage, personal injury or death.

Do not post on Slashdot after dropping acid. May cause visualizations of carnival rides, Bryan Boitano and other spinning objects.

Battery Aging (2, Insightful)

ChromaticDragon (1034458) | more than 5 years ago | (#27181335)

If this does prove to be useful for batteries, would it eliminate issues related to battery memory?

It appears current rechargeable batteries "age" due to chemical reactions even if not used. Even more so due to repeated charge cycles.

With no chemical reactions in play, does this mean people won't be forced to upgrade their phones simply because their battery is all but dead?

Re:Battery Aging (1, Insightful)

girlintraining (1395911) | more than 5 years ago | (#27181539)

With no chemical reactions in play, does this mean people won't be forced to upgrade their phones simply because their battery is all but dead?

No. There are still five year old children about, and they like taking the batteries out of things, then losing them in the toilet, the cat, the microwave... Trust me, the lack of chemical reactions doesn't diminish the need for replacement parts. -_-

Re:Battery Aging (0)

Anonymous Coward | more than 5 years ago | (#27181631)

I suddenly have an urge to put batteries in a microwave...

Re:Battery Aging (3, Funny)

aukset (889860) | more than 5 years ago | (#27181755)

like taking the batteries out of things, then losing them in the toilet, the cat, the microwave...

I suddenly have an urge to put batteries in a cat...

Re:Battery Aging (1)

bsharp8256 (1372285) | more than 5 years ago | (#27182059)

No. There are still five year old children about, and they like taking the batteries out of things, then losing them in the toilet, the cat, the microwave...

How do you lose a battery in a cat?

Re:Battery Aging (1)

DreamsAreOkToo (1414963) | more than 5 years ago | (#27181865)

Battery memory is dependent on the battery type. Nicad batteries tend to have really terrible memory, and the best way to deal with this is cycling the battery (completely discharging it and recharging it several times.) Or completely discharing/recharging it every time you use it.

Nickle Metal Hydride batteries, on the other hand, have no memory at all.

(Used to do a lot of electric RC vehicles)

sure... (0)

Anonymous Coward | more than 5 years ago | (#27181409)

but how about you wait and tell me about it WHEN I CAN GO BUY IT AT THE STORE FOR $19.99...

Re:sure... (1)

Nick Fel (1320709) | more than 5 years ago | (#27181527)

Cheapskate. Anyone who's anyone gets their batteries by funding research projects, not visiting Radio Shack.

Re:sure... (1)

dazedNconfuzed (154242) | more than 5 years ago | (#27181567)

This is /., aka "News for Nerds" - not "Consumer Reports".

I'd ask you to turn in your geek card but obviously you don't have one.

Yeah, but.. (5, Funny)

AndrewNeo (979708) | more than 5 years ago | (#27181441)

Although the actual device... cannot even light up an LED...

So you're telling me this thing is less powerful than a potato?

Re:Yeah, but.. (1)

GameMaster (148118) | more than 5 years ago | (#27181867)

Yes, but the important question is how big it is. If they created, only, a single "cell" of this tech as a proof of concept then, of course, it would be less powerful than a potato but it would also be too small to see with the naked eye. The idea would be, assuming it weren't possible to improve the efficiency of a single cell, to find a way to scale up to a huge array of these things. If they make a battery the same size as a pototoe, and it's still less powerfull, then you would have a legitimate complaint.

1nm...feasibility? (1)

martin_henry (1032656) | more than 5 years ago | (#27181471)

The next step would be to determine how this could be made more dense and mass-produced. GaAs is already a common semiconductor substrate, but how difficult is it to deposit all those layers? 1nm = 10 angstroms is pretty thin to try to make consistenly if I'm not mistaken...

so it is the electromagnetic equivelant of a gyro? (1)

way2trivial (601132) | more than 5 years ago | (#27181535)

if you spin up a mechanical flywheel, you can later pull back out the energy.
there are datacenter UPS that run on this principle.
http://www.google.com/search?hl=en&q=flywheel+ups&start=0&sa=N [google.com]

the thing is, if they get off balance, the uncontrolled release of the kinetic energy
(ooh, a car analogy) is similar to a gas tank explosion in destructive capability

What happens when the spin stored energy releases in an uncontrolled fashion?
what is the failure analysis of a commercial grade 'spin battery' going to look like?

if laptops 'splode-- buring human laps occasionally....
now imagine a spin battery rated with 10X the stored electrical juice on your lap

Re:so it is the electromagnetic equivelant of a gy (1)

Shadow-isoHunt (1014539) | more than 5 years ago | (#27181843)

You're thinking of a single rotating mass, such as a big hunk of metal cut into a flywheel. They're using lots of tiny, independent masses.

Force = mass * acceleration

Yo momma's so fat, even duracell doesn't wanna see her spin.

no, spin is quantized per particle (1)

peter303 (12292) | more than 5 years ago | (#27182377)

"More spin" is really "more aligned spin". In normal matter spin is disordered and aligned randomly in either of two states.

Wattage??? (0)

Anonymous Coward | more than 5 years ago | (#27181603)

This sounds like a cool new device. How come they can't state the actual wattage. If they said pico-watts. I would have been cool with that. I am very interested in nano-batteries and even something that produced a pico-watt would be of interest. Especially if it can scale up.and be combined with other batteries to boost the overall power.
I am not asking for the secret sauce (yet), I just want to know how excited to really get.

Spin battery? (1)

icannotthinkofaname (1480543) | more than 5 years ago | (#27181617)

It spins to produce power? And it can run my car? Does that mean that I can use a hand-crank to charge my car, just like my XO Laptop?

Hmm...maybe in addition to computers, we can bring cars to children in third-world countries with no schools....

*sees business opportunity*
*passes it up*
*waits for patent lawsuits to spring up on /. in the future, by the people who actually did do something with this*

Speaking of batteries... (1)

cagrin (146191) | more than 5 years ago | (#27181623)

Here's an old article about the battery technology of the electric car by General Motors(EV1) of the 1990's, being kept from the public by the 'Evil' oil company Chevron, buying up the patent rights to the technology from GM (also an 'Evil' company, or just plain stupid).

http://www.ev1.org/chevron.htm [ev1.org]

Is it just me? (1)

sepelester (794828) | more than 5 years ago | (#27181667)

I'm thinking space. Like in ships with huge engines and a safe way to store large amounts of power for inter-stellar travel.

If you spin it the wrong direction... (1)

Tarmus (1410207) | more than 5 years ago | (#27181679)

...would it create a black hole?

Like those deer whistlers on cars. Gotta make sure they're polarized properly.

The Nature pre-publication link (5, Informative)

Scareduck (177470) | more than 5 years ago | (#27181681)

Here's the pre-publication link in Nature [nature.com].

The electromotive force (e.m.f.) predicted by Faraday's law reflects the forces acting on the charge, â"e, of an electron moving through a device or circuit, and is proportional to the time derivative of the magnetic field. This conventional e.m.f. is usually absent for stationary circuits and static magnetic fields. There are also forces that act on the spin of an electron; it has been recently predicted that, for circuits that are in part composed of ferromagnetic materials, there arises an e.m.f. of spin origin even for a static magnetic field. This e.m.f. can be attributed to a time-varying magnetization of the host material, such as the motion of magnetic domains in a static magnetic field, and reflects the conversion of magnetic to electrical energy. Here we show that such an e.m.f. can indeed be induced by a static magnetic field in magnetic tunnel junctions containing zinc-blende-structured MnAs quantum nanomagnets. The observed e.m.f. operates on a timescale of approximately 10^2-10^3 seconds and results from the conversion of the magnetic energy of the superparamagnetic MnAs nanomagnets into electrical energy when these magnets undergo magnetic quantum tunnelling. As a consequence, a huge magnetoresistance of up to 100,000 per cent is observed for certain bias voltages. Our results strongly support the contention that, in magnetic nanostructures, Faraday's law of induction must be generalized to account for forces of purely spin origin. The huge magnetoresistance and e.m.f. may find potential applications in high sensitivity magnetic sensors, as well as in new active devices such as 'spin batteries'.

Readers with subscriptions can see the whole paper.

You 'flywheel' people do realize.. (5, Insightful)

MoellerPlesset2 (1419023) | more than 5 years ago | (#27181921)

That we're talking about _spin_ here, as in a property of subatomic particles corresponding to an 'intrinsic' angular momentum, not as in something that's physically 'spinning'. Electrons spin +1/2 or -1/2 and that's it. They can't stop. The energy here is being stored in the form of the _orientations_ of these spins, not the spin itself. What's keeping them that way is conservation of spin. Which is analogous to conservation of angular momentum. (Bound) Electrons can't change their spin state spontaneously. Which is why stuff which is magnetized stays that way for a long time. It's also the reason for phosphorescence. While I think what they've done here is undeniably pretty cool, in turning spin-state transitions into electricity directly, it's probably not going to create any real competition for conventional batteries, for fairly simple reasons. Batteries store electricity in the form of chemical redox states, which means adding/removing electrons from atoms/ions. The energy differences between spin states are typically an order of magnitude smaller than the energy difference between redox states.

Long term storage? (0)

Anonymous Coward | more than 5 years ago | (#27181949)

Have they really been able to reduce friction enough to be able to store mechanical energy for long periods of time?

Wait...Isn't this an inductor? (0)

Anonymous Coward | more than 5 years ago | (#27182085)

Device that stores energy in a magnetic field. How is this not just an inductor?

Speed (0)

Anonymous Coward | more than 5 years ago | (#27182097)

I guess if they want a car to go miles they are thinking of getting these things to spin a few thousand RPM per minute? either that or weight tons.

I guess if you ever had a car crash and the spin battery fell out of its case you would have a pretty dangerous projectile.

isnt that control magnetic energy? (1)

peter303 (12292) | more than 5 years ago | (#27182101)

Theres a limit on how much a material can be magnetized before its self-repellent magnetic energy rips it apart.

Static magnetic field? (3, Interesting)

Wilson_6500 (896824) | more than 5 years ago | (#27182375)

Spintronics is a little too far out of my ken (I was always more of a radiation physicist, where everything comes in nice little packages instead of fields), but if I'm reading the paper correctly, they're saying that they can apply a static magnetic field to one of these devices and then can measure a voltage drop across a resistor hooked up to the device. They can get a few millivolts from a 1.2 Tesla field, which persists for at least ten minutes but does decay in that time frame. When they remove the magnetic field, the voltage disappears.

I guess my question is that if the field is static, where is the energy coming from that drives the current giving rise to the voltage? I'm also wondering how one regenerates the voltage after it discharges completely.

I think I read a SF short about this years ago. (-1, Offtopic)

Anonymous Coward | more than 5 years ago | (#27182539)

A alien stranded here needed a way to signal his alien buddies, so helped in the invention of (actually, I think they were magic mufflers, but...) a technology that just happened to create a signal that would be heard halfway across the universe. I don't remember what happened next, maybe the Vulcans showed up...

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