Featured Research

from universities, journals, and other organizations

Electronics: Graphene makes a magnetic switch

Date:
July 18, 2013
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
Tiny nanoribbons of carbon could be used to make a magnetic field sensor for novel electronic devices.

Tiny nanoribbons of carbon could be used to make a magnetic field sensor for novel electronic devices.

Related Articles


Researchers in Singapore have designed an electronic switch that responds to changes in a magnetic field. The device relies on graphene, a strong and flexible electricity-conducting layer of carbon atoms arranged in a honeycomb pattern.

Seng Ghee Tan of the A*STAR Data Storage Institute, along with colleagues at the National University of Singapore, used theoretical models to predict the properties of their proposed device, known as a magnetic field-effect transistor.

The transistor is based on two nanoribbons of graphene, each just a few tens of nanometers wide, which are joined end to end. The atoms along the edges of these nanoribbons are arranged in an 'armchair' configuration -- a pattern that resembles the indented battlements of castle walls. If these edges were in a zigzag pattern, however, the material would have different electrical properties.

One of the nanoribbons in the team's transistor acts as a metallic conductor that allows electrons to flow freely; the other, slightly wider, nanoribbon is a semiconductor. Under normal conditions, electrons cannot travel from one nanoribbon to the other because their quantum wavefunctions -- the probability of where electrons are found within the materials -- do not overlap.

A magnetic field, however, warps the distribution of electrons, changing their wavefunctions until they overlap and allowing current to flow from one nanoribbon to the other. Using an external field to change the electrical resistance of a conductor in this way is known as a magnetoresistance effect.

The team calculated how electrons would travel in the nanoribbons under the influence of a 10-tesla magnetic field -- the rough equivalent of that produced by a large superconducting magnet -- at a range of different temperatures.

Tan and colleagues found that larger magnetic fields allowed more current to flow, and the effect was more pronounced at lower temperatures. At 150 kelvin, for example, the magnetic field induced a very large magnetoresistance effect and current flowed freely. At room temperature, the effect declined slightly but still allowed a considerable current. At 300 kelvin, the magnetoresistance effect was approximately half as strong.

The researchers also discovered that as the voltage across the nanoribbons increased, the electrons had enough energy to force their way through the switch and the magnetoresistance effect declined.

Other researchers recently produced graphene nanoribbons with atomically precise edges, similar to those in the proposed design. Tan and his colleagues suggest that if similar manufacturing techniques were used to build their device, its properties could come close to matching their theoretical predictions.

The A*STAR-affiliated researchers contributing to this research are from the Data Storage Institute


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. S. Bala Kumar, M. B. A. Jalil, S. G. Tan. High magnetoresistance in graphene nanoribbon heterojunction. Applied Physics Letters, 2012; 101 (18): 183111 DOI: 10.1063/1.4765364

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Electronics: Graphene makes a magnetic switch." ScienceDaily. ScienceDaily, 18 July 2013. <www.sciencedaily.com/releases/2013/07/130718100804.htm>.
The Agency for Science, Technology and Research (A*STAR). (2013, July 18). Electronics: Graphene makes a magnetic switch. ScienceDaily. Retrieved November 27, 2014 from www.sciencedaily.com/releases/2013/07/130718100804.htm
The Agency for Science, Technology and Research (A*STAR). "Electronics: Graphene makes a magnetic switch." ScienceDaily. www.sciencedaily.com/releases/2013/07/130718100804.htm (accessed November 27, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Thursday, November 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA's First 3-D Printer In Space Creates Its First Object

NASA's First 3-D Printer In Space Creates Its First Object

Newsy (Nov. 26, 2014) The International Space Station is now using a proof-of-concept 3D printer to test additive printing in a weightless, isolated environment. Video provided by Newsy
Powered by NewsLook.com
Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Reuters - Innovations Video Online (Nov. 26, 2014) Innovative recycling project in La Paz separates city waste and converts plastic garbage into school furniture made from 'plastiwood'. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Blu-Ray Discs Getting Second Run As Solar Panels

Blu-Ray Discs Getting Second Run As Solar Panels

Newsy (Nov. 26, 2014) Researchers at Northwestern University are repurposing Blu-ray movies for better solar panel technology thanks to the discs' internal structures. Video provided by Newsy
Powered by NewsLook.com
Today's Prostheses Are More Capable Than Ever

Today's Prostheses Are More Capable Than Ever

Newsy (Nov. 26, 2014) Advances in prosthetics are making replacement body parts stronger and more lifelike than they’ve ever been. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins