Scientists make magnetic new graphene discovery

Apr 14, 2011
Schematic of a graphene transistor showing graphene (red), gold electrodes (yellow), silicon dioxide (clear) and silicon substrate (black). Inset shows the graphene lattice with vacancy defects. Vacancies (missing atoms) are shown surrounded by blue carbon atoms.

(PhysOrg.com) -- University of Maryland researchers have discovered a way to control magnetic properties of graphene that could lead to powerful new applications in magnetic storage and magnetic random access memory.

The finding by a team of Maryland researchers, led by Physics Professor Michael S. Fuhrer of the UMD Center for Nanophysics and Advanced Materials is the latest of many amazing properties discovered for .

A honeycomb sheet of just one atom thick, graphene is the basic constituent of graphite. Some 200 times stronger than steel, it conducts electricity at room temperature better than any other known material (a 2008 discovery by Fuhrer, et. al). Graphene is widely seen as having great, perhaps even revolutionary, potential for nanotechnology applications. The 2010 Nobel Prize in physics was awarded to scientists Konstantin Novoselov and Andre Geim for their 2004 discovery of how to make graphene.

In their new graphene discovery, Fuhrer and his University of Maryland colleagues have found that missing atoms in graphene, called vacancies, act as -- they have a "magnetic moment." Moreover, these magnetic moments interact strongly with the electrons in graphene which carry electrical currents, giving rise to a significant extra electrical resistance at low temperature, known as the Kondo effect. The results appear in the paper "Tunable Kondo effect in graphene with defects" published this month in .

The Kondo effect is typically associated with adding tiny amounts of magnetic metal atoms, such as iron or nickel, to a non-magnetic metal, such as gold or copper. Finding the Kondo effect in graphene with vacancies was surprising for two reasons, according to Fuhrer.

"First, we were studying a system of nothing but carbon, without adding any traditionally magnetic impurities. Second, graphene has a very small , which would be expected to make the Kondo effect appear only at extremely low temperatures," he said.

The team measured the characteristic temperature for the Kondo effect in graphene with vacancies to be as high as 90 Kelvin, which is comparable to that seen in metals with very high electron densities. Moreover the Kondo temperature can be tuned by the voltage on an electrical gate, an effect not seen in metals. They theorize that the same unusual properties of that result in graphene's electrons acting as if they have no mass also make them interact very strongly with certain kinds of impurities, such as vacancies, leading to a strong Kondo effect at a relatively high temperature.

Fuhrer thinks that if vacancies in graphene could be arranged in just the right way, ferromagnetism could result. "Individual magnetic moments can be coupled together through the Kondo effect, forcing them all to line up in the same direction," he said.

"The result would be a ferromagnet, like iron, but instead made only of carbon. Magnetism in graphene could lead to new types of nanoscale sensors of magnetic fields. And, when coupled with graphene's tremendous electrical properties, magnetism in graphene could also have interesting applications in the area of spintronics, which uses the magnetic moment of the electron, instead of its electric charge, to represent the information in a computer.

"This opens the possibility of 'defect engineering' in graphene - plucking out atoms in the right places to design the magnetic properties you want," said Fuhrer.

Explore further: Imaging electric charge propagating along microbial nanowires

More information: www.nature.com/nphys/journal/v… /full/nphys1962.html

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OdieNewton
5 / 5 (4) Apr 14, 2011
It's a pity that in a few years, when all of this has been implemented in technology, the greater majority of people will just think, "Oh, they made my iPhone faster." I love seeing all these discoveries about graphene; I get giddy imagining everything that it will do for our tech.
eachus
5 / 5 (3) Apr 14, 2011
It's a pity that in a few years, when all of this has been implemented in technology, the greater majority of people will just think, "Oh, they made my iPhone faster."


You are thinking inside the box. To me the most important property of graphene is its biocompatibility. In a few years getting a new phone will involve pulling the old one out from under your scalp, and putting a new one in.* The phone will connect with your brain through TMI (transcranial magnetic induction) so making a biocompatible ferromagnet is a big deal.

* A few years after that, it will all be done with nanomachines. Take a pill and wait a few minutes. ;-)
Quantum_Conundrum
2 / 5 (4) Apr 14, 2011
eachus:

So basicly you're saying humanity will turn into the Borg...

I mean, if half the people get implants and become super-humans, the other half will be forced to do the same to compete in whatever job market remains, seeing as how androids will do all the menial tasks anyway...

So what is your vision of the future? A capitalistic Borg, instead of the Communistic Borg of Star Trek?

Which is worse, I wonder?
jscroft
4 / 5 (4) Apr 14, 2011
Ah, yes. We'd all be SO much better off if we'd just stayed in the cave with the dolts who couldn't quite get the hang of the new stone "tools".
ZephirAWT
Apr 14, 2011
This comment has been removed by a moderator.
kaasinees
1 / 5 (1) Apr 14, 2011
What i wonder is that if the borg are so superior what would their incentive be to assimilate?
Are they not able to produce scientific advances anymore?
ZephirAWT
Apr 14, 2011
This comment has been removed by a moderator.
Quantum_Conundrum
not rated yet Apr 14, 2011
What i wonder is that if the borg are so superior what would their incentive be to assimilate?
Are they not able to produce scientific advances anymore?


Well, you have to figure in Star Trek different types of aliens have different types of mental abilities, so the Borg believe they benefit from enslaving all life to aquire all knowledge and attributes.

They also only assimilate species which they believe have some quality or tecnology that makes them "relevant" or worthy. So for example, they will totally ignore a species that appears to have no advanced technology.

And to answer your question, no, actually, in the series, the Borg do a lot of "inventing" on their own in addition to what they steal and assimilate from others.

My point was I don't think that's a good way to go for humanity.
Quantum_Conundrum
1 / 5 (1) Apr 14, 2011
Ah, yes. We'd all be SO much better off if we'd just stayed in the cave with the dolts who couldn't quite get the hang of the new stone "tools".


Stone tools is one thing, but implanting machines in our brains is quite another.

You are talking about, eventually, the total lack of any privacy whatsoever, even in your own mind.

Imagine what hackers, or the government, or corporations will do when they figure out how to control your implants, for example.

Imagine if everyone knew everything you've ever done, or thought about doing.
ZephirAWT
Apr 14, 2011
This comment has been removed by a moderator.
OdieNewton
1 / 5 (1) Apr 14, 2011
Senile people and 93.4% of physorg comment-ees
El_Nose
not rated yet Apr 14, 2011
@eachus

some inside of the box thinking for you

personal information storage that resides on your person literally... imagine having a harddrive that lives inside of you - recording all you biorythms coupled with blood chemistry analysis - your body would be constantly monitoring itself and updating your physicians database on your heart rate, hormone levels, odd chemical signatures in your blood... there are cancers that can be determined by a few blood tests -- well the second you begin to go down that road you doctor calls you in to confirm and you have a quick out patient surgery to remove the tumor growth that because you caught it 3 days in development is reall really small and there you go.

How about recording your daily life -- if we could ever learn to 'read' the sensory data the eyes and ears take in then we could record an entire life -- NOT sure if that is desirable - but 80% homicides and rapes would now lead to convictions.

I have a lot of other ideas
El_Nose
not rated yet Apr 14, 2011
@ QC

Can every computer be hacked -- no -- is every computer vunerable -- yes

I have a few puters i keep off of any network - they are only hackable by physical manipulation - you have to come into my house and touch the machine

There are computer netowrks out there that are pretty much unhackable because of restrictionof knowledge -- in college i worked on a Dod project that dealt with a secure resource - the protocol for online manipulation of that resource was known by very few people -- so most attacks on said resource was driven by people with inside knowledge -- so very hard to attack

My point is not everything HAS to be networked -- and if the resource is very important - such as access to something that interacts with your body directly - then obscure protocols that require levels of access to even learn help deter criminal activity
MorituriMax
5 / 5 (1) Apr 14, 2011
eachus:

So basicly you're saying humanity will turn into the Borg...

I mean, if half the people get implants and become super-humans, the other half will be forced to do the same to compete in whatever job market remains, seeing as how androids will do all the menial tasks anyway...

So what is your vision of the future? A capitalistic Borg, instead of the Communistic Borg of Star Trek?

Which is worse, I wonder?


I'll tell you what's worse. Assuming because of some arbitrary notion in your mind that only half of the people will have it. It's typical us-versus-them technophobia. I see that this will be as accessible to everyone who is born as getting slapped on the bottom when you pop out. For all we know, the nano-tech will get passed straight from the mother to the child while it is in the womb, granting other health and mental benefits to newborns.
MorituriMax
5 / 5 (1) Apr 14, 2011
As for the knee jerk fear that "humanity will turn into the Borg",

Wow, let's assume the worst for the future because somebody in Hollywood took some tidbits from culture and used it to make a boogeyman for the good guys to fight in a TV series. I'm not that worried because, worst case, if we do turn into the Borg, we'll be the baddest asses in our galaxy. Whoopee doo.

How about we give equal time to the good things that can happen as well as the cheesy cliche'd sci-fi memes floating around.
eachus
not rated yet Apr 15, 2011
Imaging the bad things that can happen early enough to avoid them, is one of the uses of science fiction. To me, the Borg are practically cardboard cutouts of villains necessary to advance the plot--a real Borg-like shared intelligence would be so alien that even basic communication would be next to impossible. (I can recommend a few hundred books on how language affects the way people think. And the a Borg like entity would have layers of communication protocols, just like the internet. And for the intelligent nodes, most of those protocols and languages would not be consciously be noticed. Think about trying to figure out internet traffic by looking at hundreds or thousands of packet sources and sinks. But you don't have a packet sniffer, you start not even knowing what packets are.

But what about us? Good news and bad news...
eachus
not rated yet Apr 15, 2011
There will always be a portion of the population who "don't have the time for all of this," and reuse simple to guess passwords. Another fraction will "get it," and knows enough to lock their body from the inside.

Personal computers hooked to the Internet 24/7 give you some idea of what things will be like. Those who are willing to devote the time and energy to being secure, will basically be secure. They will occasionally get infected, but as long as the problem is detected early, and treated quickly, they will remain themselves.

On the other hand tomorrow's (heck it is pretty much tomorrow already) equivalent of unprotected sex will be unprotected data sharing. I've already heard many "hard luck" stories from people who trusted their spouses with their passwords. After all they share everything else, right? If you do, don't be surprised when some day you find your life in shreds--porn e-mailed to your friends and co-workers--and boss.
Beard
not rated yet Apr 16, 2011
We are humanity.
We embrace new technology and are empowered by it.
We adapt to new threats and protect ourselves from them.
Resistance is futile.

Cynical1
not rated yet Apr 16, 2011
It's the new face of evolution...