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"Spin Battery" Effect Discovered
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.'"
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.
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Readers with subscriptions can see the whole paper.
Dog is my co-pilot.
Simpsons season 6, episode 21 ("The PTA Disbands").
Support Right To Repair Legislation.
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.
Prediction: The real iPhone killer is going to be sex robots from Japan. Think about it.
Bypassing the layers of blogs, here's the actual paper. But it costs $32 to read more than the abstract.
This is an application of superparamagnetism. Paramagnetism is ordinarily a weak phenomenon, but there are some new materials for which this effect is much stronger.
It's too early to tell if this is useful. Right now, it's in the category of "minor development in materials science overpromoted as a major breakthrough". It might turn out to have some relevance to MRI imaging or disk drives, both of which rely on fine-scale magnetic effects.
"Which is how does a device that stores an electrical charge (a battery) via magnetism not go dead based simply on inductive coupling with nearby metals?"
Firstly, inductive coupling requires time dependent magnetic fields and probably realistically macroscopically reinforcing ones so that the field strength is appreciable at a distance.
And then it could be locally thermodynamically stable, like opposing domains on a ferromagnetic surface, like a hard drive.
Hard drives wont to spontaneously erase themselves to 'all zero' over human lifetimes.
The global lowest energy state is "all spins pointing the same way".
In THIS house, we obey the laws of thermodynamics.
Like other posters pointed out: you likely don't know what thermodynamics even is. Hint: thermo has something to do with temperature. Thermodynamcs is about entropy and heat not about magnetic fields or electric fields.
To your question:
In other words -- what's preventing the battery from discharging?
The battery does not discharge in the same way your hard drive is not losing its content just so. The magnetic fields in such a device are static that means they don't move, that means they don't induce anything to anything. However if you read the article (yes the linked article, you can read it, you know!!) you find that nanoscale areas are magnetized and that tunnel effects are involved. I guess that such small areas can "discharge" randomly vie tunnel effects (similar to radioactive decay).
angel'o'sphere
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
What?
LED's require very little "juice". The quote from wikipedia just means they don't handle fluctuations very well. i.e. if you don't give them a high enough voltage or give them too high a current they just don't work as efficiently.
Here is another quote from the same f'n page: "LEDs produce more light per watt than incandescent bulbs." http://en.wikipedia.org/wiki/Led#Advantages
They'll never build skyscrapers out of synth spider silk because the wrong kind of strength is required. Silk's strength is pull strength like that of wire rope. But, for a skyscraper the strength required is compresion and torsion.
But it would be nice to see a bridge made of a synth silk material
I don't know of any common light sources that are more efficient than LEDs.
I don't think you understand the meaning of that Wikipedia quote.
The Voltage "above the threshold" means the voltage to cause the NP junction to conduct. In most diodes, that is .7 volts.
The part about "a current below the rating", means that if you present enough voltage across the PN junction, as to reach the current limit of the PN junction, it will fail.
--fatboy