Featured Research

from universities, journals, and other organizations

Understanding next-generation electronic devices: Smallest atomic displacements ever

Date:
September 3, 2011
Source:
European Synchrotron Radiation Facility
Summary:
Scientists have developed a novel X-ray technique for imaging atomic displacements in materials with unprecedented accuracy. They have applied their technique to determine how a recently discovered class of exotic materials -- multiferroics -- can be simultaneously both magnetically and electrically ordered. Multiferroics are also candidate materials for new classes of electronic devices. The discovery is a major breakthrough in understanding multiferroics.

This photo shows the sample holder, made of copper, which was used in the experiment. The small gray crystal of TbMnO3 that was studied, is in the center, between two electrodes to apply an electric field.
Credit: Image courtesy of Luigi Paolasini

An international team of scientists has developed a novel X-ray technique for imaging atomic displacements in materials with unprecedented accuracy. They have applied their technique to determine how a recently discovered class of exotic materials -- multiferroics -- can be simultaneously both magnetically and electrically ordered. Multiferroics are also candidate materials for new classes of electronic devices.

The discovery, a major breakthrough in understanding multiferroics, is published in Science dated 2 September 2011.

The authors comprise scientists from the European Synchrotron Radiation Facility (ESRF) in Grenoble (France), the University of Oxford and the University College London (both UK). Helen Walker from the ESRF is the main author of the publication.

Everybody is familiar with the idea that magnets are polarized with a north and a south pole, which is understood to arise from the alignment of magnet moments carried by atoms in magnetic materials. Certain other materials, known as ferroelectrics, exhibit a similar effect for electrical polarisation. The exotic "multiferroic" materials combine both magnetic and ferroelectric polarizations, and can exhibit a strong coupling between the two phenomena.

This leads to the strange effect that a magnetic field can electrically polarise the material, and an electric field magnetise it. A class of strong multiferroics was discovered ten years ago and has since led to a new, rapidly growing field of research, also motivated by the promise of their exotic properties for new electronic devices. One example is a new type of electronic memory, in which an electric field writes data into the memory and a magnetic detector is used to read it. This process is faster, and uses less energy than today's hard disk drives.

However, the origin of the electric polarisation in multiferroics remained mostly elusive to date. The team's work unambiguously shows that the polarization in the multiferroic studied proceeds from the relative displacement of charges of different signs, rather than the transfer of charge from one atom to another.

As the displacement involves a high number of electrons, even small distances can lead to significant polarisation. The actual distance of the displacement still came as a surprise: about 20 femtometres, or about 1/100,000th of the distance between the atoms in the material. Measuring such small displacements was actually believed to be impossible.

"I think that everyone involved was surprised, if not staggered, by the result that we can now image the position of atoms with such accuracy. The work is testament to the fantastic facilities available in Grenoble to the UK science community," says Prof. Des McMorrow, Deputy Director of the London Centre for Nanotechnology, leader of the UCL part of the project.

Walker and her colleagues developed a smart new experimental technique exploiting the interference between two competing processes: charge and magnetic scattering of a powerful, polarized X-ray beam. They studied a single crystal of TbMnO3 which shows a strong multiferroic coupling at temperatures below 30K, and were able to measure the displacements of specific atoms within it with an accuracy approaching one femtometre (10-15m). The atoms themselves are spaced apart 100,000 times this distance.

The new interference scattering technique has set a world record for accuracy in absolute measurements of atomic displacements. (It is also the first measurement of magnetostriction in antiferromagnets.) Most significantly the identification of the origin of ferroelectricty in a multiferroic material is a major step forward in the design of multiferroics for practical applications.

"By revealing the driving mechanism behind multiferroics, which offer so many potential applications, it underlines how experiments designed to understand the fundamental physics of materials can have an impact on the wider world," concludes Dr. Helen Walker who led the work at the ESRF.


Story Source:

The above story is based on materials provided by European Synchrotron Radiation Facility. Note: Materials may be edited for content and length.


Journal Reference:

  1. H. C. Walker, F. Fabrizi, L. Paolasini, F. De Bergevin, J. Herrero-Martin, A. T. Boothroyd, D. Prabhakaran, D. F. Mcmorrow. Femtoscale Magnetically Induced Lattice Distortions in Multiferroic TbMnO3. Science, 2 September 2011: Vol. 333 no. 6047 pp. 1273-1276 DOI: 10.1126/science.1208085

Cite This Page:

European Synchrotron Radiation Facility. "Understanding next-generation electronic devices: Smallest atomic displacements ever." ScienceDaily. ScienceDaily, 3 September 2011. <www.sciencedaily.com/releases/2011/09/110901142058.htm>.
European Synchrotron Radiation Facility. (2011, September 3). Understanding next-generation electronic devices: Smallest atomic displacements ever. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2011/09/110901142058.htm
European Synchrotron Radiation Facility. "Understanding next-generation electronic devices: Smallest atomic displacements ever." ScienceDaily. www.sciencedaily.com/releases/2011/09/110901142058.htm (accessed July 31, 2014).

Share This




More Matter & Energy News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
Smartphone Powered Paper Plane Debuts at Airshow

Smartphone Powered Paper Plane Debuts at Airshow

AP (July 30, 2014) Smartphone powered paper airplane that was popular on crowdfunding website KickStarter makes its debut at Wisconsin airshow (July 30) Video provided by AP
Powered by NewsLook.com
U.K. To Allow Driverless Cars On Public Roads

U.K. To Allow Driverless Cars On Public Roads

Newsy (July 30, 2014) Driverless cars could soon become a staple on U.K. city streets, as they're set to be introduced to a few cities in 2015. 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:
from the past week

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