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The Best Refrigerator Magnet Ever?
ScienceNOW ^ | March 19, 2010 | Adrian Cho

Posted on 03/20/2010 7:31:27 PM PDT by neverdem

Enlarge Image
sn-magnetics.jpg
Limit breaker? The crystal structure of Fe16N2, which one group of researchers says beats the predicted limit for magnetism in a material.
Credit: Jian-Ping Wang

PORTLAND, OREGON—There are limits to just how magnetic a material can be. Or so researchers thought. A compound of iron and nitrogen is about 18% more magnetic than the most magnetic material currently known, a team of materials scientists claims. If such magnets could be produced commercially, they could, for example, allow electronics manufactures to equip computer hard drives with smaller "write heads" capable of cramming them with more information. Other researchers are reacting to the announcement with caution, however, as similar claims about the controversial material have fallen through in the past.

A material's magnetism originates with its spinning electrons. Each electron acts like a little magnet with its field aligned with the axis of its spin, and when more electrons spin in one direction than in the opposite direction, the material becomes magnetic. For example, an iron atom has four more electrons spinning one way than the other. In a bulk material, the situation is more complicated, as the electron clouds of individual atoms merge into riverlike bands. Electrons spinning "up" flow in different bands from those spinning "down," and the difference between the numbers of highest-energy electrons in the up bands and the down bands determines the material's magnetism—which is smaller than one might expect from the magnetism of a single atom. Using such band theory, researchers can predict which material should have the largest magnetism: iron cobalt.

However, Jian-Ping Wang, a materials physicist at the University of Minnesota, Twin Cities, and colleagues say that a compound of eight parts iron and one part nitrogen, Fe16N2, exceeds this limit by roughly 18%. The key to the material's extremely high magnetism lies in its complicated crystal structure, Wang reported here yesterday at the March Meeting of the American Physical Society. Probing their samples with x-ray, the researchers determined that within them, each nitrogen atom sits in the center of a cluster of six iron atoms and that a couple more iron atoms sit between neighboring clusters. The electrons flowing between the clusters act much like electrons in ordinary iron. But the electrons in the iron atoms in the clusters tend to get stuck, or "localized," where they are. As a result, Wang says, those atoms contribute more like individual atoms to the overall magnetism, driving it way up.

"If it's right, it's super important," says Eric Fullerton, a physicist at the University of California, San Diego. But he stresses the "if." As Wang himself explained, as early as 1972, others had claimed that Fe16N2 is extraordinarily magnetic. In the 1990s, researchers with the Japanese high-tech company Hitachi reported observations that seemed to bolster those claims. However, the evidence was problematic in several ways, Fullerton says. For example, some of the results depended on tricky estimations of exactly what fraction a sample's volume consisted of Fe16N2, which is metastable and tends to fall apart into other crystal structures. Others have not been able to reproduce the Hitachi results, Fullerton says.

Wang, however, says his team has been honing its techniques for years and can now reliably grow samples of Fe16N2. The researchers have also measured the magnetization with a technique called x-ray magnetic circular dichroism, which compares the material's ability to absorb x-ray light whose polarization twirls to the right or to the left. That measure is less sensitive to volume effects than earlier techniques and directly detects the localized electrons, Wang says. The team has also cranked out detailed "first principles" simulations that show the emergence of the localized electrons and make the whole scenario hang together, Wang says.

"He's been able to control things a lot better than other people," says Alan Edelstein, a physicist at the U.S. Army Research Laboratory in Adelphi, Maryland. Still, he hesitates to say it's a done deal. "I think this will be followed up on. We're going to know if this is right." At the very least, Fe16N2 continues to exert its extraordinary pull on the minds of physicists and material scientists.


TOPICS: Culture/Society; News/Current Events; Technical
KEYWORDS: magnetism; materialsscience; stringtheory; tech; technology

1 posted on 03/20/2010 7:31:27 PM PDT by neverdem
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To: neverdem

Interesting! If you can increase the strength of a magnetic field, it can potentially generate that much more electricity...


2 posted on 03/20/2010 7:36:42 PM PDT by Bean Counter (I keeps mah feathers numbered, for just such an emergency...)
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To: neverdem

The last thing I need is a Wang magnet on the fridge.


3 posted on 03/20/2010 7:37:21 PM PDT by Fester Chugabrew
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To: neverdem

Interesting


4 posted on 03/20/2010 7:43:20 PM PDT by Fiddlstix (Warning! This Is A Subliminal Tagline! Read it at your own risk!(Presented by TagLines R US))
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To: Fester Chugabrew

If this works and doesn’t have some unknown limitation (temperature, etc) this is amazing because it doesn’t use rare earths like neodymium (which are, not surprisingly, “rare”). I’ve read articles that supplies of rare earths might limit the growth of electric cars in the future. BTW, every hard disk made in at least the last 10 years contains one or two neodymium-based magnets.


5 posted on 03/20/2010 7:50:33 PM PDT by The Antiyuppie ("When small men cast long shadows, then it is very late in the day.")
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To: neverdem
If configured in a Y formation and supplied with 1.21 gigawatts of electricity, such a material can finally produce the flux capacitor for my Delorean.
6 posted on 03/20/2010 7:51:06 PM PDT by IrishCatholic (No local Communist or Socialist Party Chapter? Join the Democrats, it's the same thing!)
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To: Fester Chugabrew
I know what you mean. Guess the wife will have to fetch the beers!
7 posted on 03/20/2010 7:52:03 PM PDT by mad_as_he$$
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To: neverdem

A gassy magnet, eh? Who knew?


8 posted on 03/20/2010 7:52:11 PM PDT by Jack Hydrazine
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To: Bean Counter

Yeah, now they can shrink motors and generators down without reducing power. Cordless power tools and remote control airplanes will benefit.


9 posted on 03/20/2010 7:52:38 PM PDT by mamelukesabre (Si Vis Pacem Para Bellum (If you want peace prepare for war))
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To: neverdem

A very attractive idea...


10 posted on 03/20/2010 7:56:38 PM PDT by Yo-Yo (Is the /sarc tag really necessary?)
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To: mad_as_he$$

You sir are doomed, if she figures this out.................

mrs

jus sayin


11 posted on 03/20/2010 8:01:58 PM PDT by proudmilitarymrs (New Jersey has no soul, only taxes, and a new Gov, we'll see!)
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To: neverdem

IT does NOT require exotic rare earth elements in its composition, of which, China controls 95% of the worlds supply via two mines in Mongolia. I hope they can do something with it.


12 posted on 03/20/2010 8:01:59 PM PDT by givemELL (Does Taiwan Meet the Criteria to Qualify as an "Overseas Territory of the United States"? by Richar)
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To: neverdem

13 posted on 03/20/2010 8:08:00 PM PDT by Last Dakotan
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To: IrishCatholic

So just hook it up to the light on the courthouse.


14 posted on 03/20/2010 8:16:48 PM PDT by GGpaX4DumpedTea (I am a tea party descendant - steeped in the Constitutional legacy handed down by the Founders)
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To: SirKit

Magnetism ping!!


15 posted on 03/20/2010 8:51:12 PM PDT by SuziQ
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To: The Antiyuppie
The internet server at my school blew six of its hard drives. The IT guy said I could have them. I spent an afternoon taking them all apart. There were a pair of seriously strong magnets in each, strong enough to attract each other through my hand. Very strong. Would it be possible to create a generator using them? As for the fridge, my kids' artwork and all the photos are safe. REALLY safe!
16 posted on 03/20/2010 11:59:29 PM PDT by Othniel (Meddlng in human affairs for 1/20th of a millennium.......)
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To: neverdem

He’ll make a bundle selling refrigerator magnets... :-)


17 posted on 03/21/2010 1:23:00 AM PDT by Star Traveler (Remember to keep the Messiah of Israel in the One-World Government that we look forward to coming)
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To: proudmilitarymrs

lol...quite possible.


18 posted on 03/21/2010 6:03:53 AM PDT by mad_as_he$$
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To: Othniel

“Would it be possible to create a generator using them? As for the fridge, my kids’ artwork and all the photos are safe. REALLY safe!”

Yes, they are fun, but they are so strong that they can be dangerous (pinching fingers, for example). The metal is also brittle and if they hit each other too hard the metal can shatter and send sharp pieces all over the place.


19 posted on 03/21/2010 8:02:46 AM PDT by The Antiyuppie ("When small men cast long shadows, then it is very late in the day.")
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To: Last Dakotan

Is it real and where can I get one.


20 posted on 03/21/2010 8:07:41 AM PDT by Yardstick
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To: Fester Chugabrew

I knew a chick in high school that was a regular wang magnet.


21 posted on 03/21/2010 8:10:52 AM PDT by Tijeras_Slim (Live jubtabulously!)
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To: Yardstick
I guess they don't make it anymore...

http://www.vat19.com/dvds/magnetic-bottle-opener.cfm?adid=shareasale

22 posted on 03/21/2010 5:19:21 PM PDT by Last Dakotan
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To: AdmSmith; bvw; callisto; ckilmer; dandelion; ganeshpuri89; gobucks; KevinDavis; Las Vegas Dave; ...
Thanks neverdem.
The crystal structure of Fe16N2, which one group of researchers says beats the predicted limit for magnetism in a material.
That oughtta teach people to predict limits.

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23 posted on 03/22/2010 5:42:44 PM PDT by SunkenCiv (http://themagicnegro.com/)
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To: neverdem
thanks, for the information / thread.

24 posted on 03/23/2010 9:00:44 AM PDT by skinkinthegrass (Zer0 to the voters: "Here's my DeathCARE Plan"...now....just die (quicky), please. :^)
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