Welcome to the GoFuckYourself.com - Adult Webmaster Forum forums.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact us.

Post New Thread Reply

Register GFY Rules Calendar
Go Back   GoFuckYourself.com - Adult Webmaster Forum > >
Discuss what's fucking going on, and which programs are best and worst. One-time "program" announcements from "established" webmasters are allowed.

 
Thread Tools
Old 03-14-2004, 11:09 PM   #1
Juicy D. Links
So Fucking Banned
 
Industry Role:
Join Date: Apr 2001
Location: N.Y. -Long Island --
Posts: 122,992
Carbon nanotubes go magnetic



Physicists have shown that carbon nanotubes can become magnetized when they are placed in contact with a magnetic material. Michael Coey of Trinity College in Dublin and colleagues believe the mechanism relies on the transfer of spin - carried by electrons - from the magnetic substrate to the nanotube (O Céspedes et al. 2004 J. Phys.: CM 16 L155).

It is widely believed that graphite and other forms of carbon can have ferromagnetic properties, but the effects are so weak that physicists are not sure if the magnetism is due to tiny amounts of iron-rich impurities, or if it is an intrinsic property of the carbon. In 2002 Coey's group measured the magnetic properties of a meteorite sample and found that only two-thirds of the magnetization could be accounted for by magnetic minerals present in the sample. The rest, they argued, must come from the carbon. In particular, they proposed that ferromagnetic nanocrystals in the sample induced a magnetic moment in the carbon via proximity effects.



Modelling magnetic nanotubes

Subsequent theoretical work by Mauro Ferreira and Stefano Sanvito showed that a measurable magnetic moment could be produced in carbon nanostructures if they were placed close to a ferromagnetic surface. Now, the team has confirmed these predictions in experiments with multi-walled carbon nanotubes that have been shown to be free from magnetic impurities.

Coey says that the main challenge in his experiment was to measure the tiny magnetic moment of the nanotubes over the large background magnetic moment coming from the magnetic material. To overcome this, the team placed the nanotubes onto ferromagnetic substrates that had been uniformly magnetized in one direction. This ensured that no stray fields were produced by the substrate. However, the nanotubes did produce a sizeable stray field when placed on the surface, and the Dublin team was able to measure this with a magnetic force microscope. Moreover, nanotubes placed on non-magnetic substrates, such as silicon or gold, showed no magnetization.



Micrographs

The group calculated the average room temperature magnetization in the nanotubes to be 0.1 Bohr magnetons per carbon atom. By comparison, the figure for iron is 2.2. "This work opens new avenues for magneto-electronics," Coey told PhysicsWeb. "For instance, one can foresee devices where the magnetic and electrical contacts are separated. The magnetic contact could be used to magnetically polarize the nanotubes - and to manipulate the spins - while the non-magnetic contacts are used as current/voltage electrodes."
Juicy D. Links is offline   Share thread on Digg Share thread on Twitter Share thread on Reddit Share thread on Facebook Reply With Quote
Old 03-15-2004, 06:35 AM   #2
Juicy D. Links
So Fucking Banned
 
Industry Role:
Join Date: Apr 2001
Location: N.Y. -Long Island --
Posts: 122,992
your thoughts?
Juicy D. Links is offline   Share thread on Digg Share thread on Twitter Share thread on Reddit Share thread on Facebook Reply With Quote
Old 03-15-2004, 07:27 AM   #3
radical
Confirmed User
 
Join Date: Oct 2003
Location: Bonnie Scotland
Posts: 2,876
Was nano technology not supposed to be getting banned or something??

I know here in the uk the government is investing heavily into it!!
__________________




ICQ: 166108967
radical is offline   Share thread on Digg Share thread on Twitter Share thread on Reddit Share thread on Facebook Reply With Quote
Post New Thread Reply
Go Back   GoFuckYourself.com - Adult Webmaster Forum > >

Bookmarks



Advertising inquiries - marketing at gfy dot com

Contact Admin - Advertise - GFY Rules - Top

©2000-, AI Media Network Inc



Powered by vBulletin
Copyright © 2000- Jelsoft Enterprises Limited.