Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > ORNL microscopy inspires flexoelectric theory behind 'material on the brink'

Abstract:
Electron microscopy, conducted as part of the Shared Research Equipment (ShaRE) User Program at the Department of Energy's Oak Ridge National Laboratory, has led to a new theory to explain intriguing properties in a material with potential applications in capacitors and actuators.

ORNL microscopy inspires flexoelectric theory behind 'material on the brink'

Oak Ridge, TN | Posted on April 14th, 2012

A research team led by ORNL's Albina Borisevich examined thin films of bismuth samarium ferrite, known as BSFO, which exhibits unusual physical properties near its transition from one phase to another. BSFO holds potential as a lead-free substitute for lead zirconium titanate (PZT), a similar material currently used in dozens of technologies from sensors to ultrasound machines.

Materials such as BSFO and PZT are often called "materials on the brink" in reference to their enigmatic behavior, which is closely tied to the transition between two different phases. These phases are characterized by structural changes in the material that produce different electrical properties.

"The best properties of the material are found at this transition," Borisevich said. "However, there has been a lot of discussion about what exactly happens that leads to an enhancement of the material's properties."

Using scanning transmission electron microscopy, the team mapped the position of atoms in BSFO films to find what happens to the local structure at the transition between ferroelectric and antiferroelectric phases. The team's results are published in Nature Communications.

"We discovered that neither of the two dominant theories could describe the observed behavior at the atomic scale," Borisevich said.

Some theorists have proposed that the material forms a nanocomposite at the transition. In this case, the energy of the boundaries between phases would have to approach zero, but Borisevich's team found experimentally something entirely different: the boundary's energy was instead effectively negative.

"When the energy of boundary is negative, it means that the system wants to have as many boundaries as possible, but with atom sizes being finite, you can't increase it to infinity," Borisevich said. "So you have to stop at some short-period modulated structure, which is what happens here."

Based on its observations, the team concluded that the mechanism behind the observed behavior was linked to a relatively weak interaction called flexoelectricity.

"Flexoelectricity means that you bend a material and it polarizes," said ORNL coauthor Sergei Kalinin. "It's a property present in most ferroelectrics. The effect itself is not necessarily very strong on macroscopic scales, but with the right conditions, which are realized in nanoscale systems, it can produce very interesting consequences."

Borisevich adds that the team's approach can be used to investigate a variety of systems with similar phase boundaries, and she emphasizes the importance of mapping out materials at the atomic scale.

"In this particular case, electron microscopy is the only way to look at very local changes because this material is a periodic structure," she said. "The decisive atomic-scale information had been missing from the discussion."

Researchers include National Academy of Sciences of Ukraine's Eugene Eliseev and Anna Morozovska; University of New South Wales's Ching-Jung Cheng and Valanoor Nagarajan; National Chiao Tung University's Jiunn-Yuan Lin and Ying-Hao Chu; and University of Maryland's Daisuke Kan and Ichiro Takeuchi. The full paper is available online here: www.nature.com/ncomms/journal/v3/n4/full/ncomms1778.html.

This work was supported by DOE's Office of Science, which sponsors the Shared Research Equipment (ShaRE) User Facility.

####

About Oak Ridge National Laboratory
ORNL is managed by UT-Battelle for the Department of Energy's Office of Science. DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov

For more information, please click here

Contacts:
Morgan McCorkle
Communications and Media Relations
865.574.7308

Copyright © Oak Ridge National Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Imaging

Clues to inner atomic life from subtle light-emission shifts: Hyperfine structure of light absorption by short-lived cadmium atom isotopes reveals characteristics of the nucleus that matter for high precision detection methods July 3rd, 2015

NIST ‘How-To’ Website Documents Procedures for Nano-EHS Research and Testing July 1st, 2015

News and information

Clues to inner atomic life from subtle light-emission shifts: Hyperfine structure of light absorption by short-lived cadmium atom isotopes reveals characteristics of the nucleus that matter for high precision detection methods July 3rd, 2015

Pioneering Southampton scientist awarded prestigious physics medal July 3rd, 2015

Groundbreaking research to help control liquids at micro and nano scales July 3rd, 2015

Discovery of nanotubes offers new clues about cell-to-cell communication July 2nd, 2015

Laboratories

Influential Interfaces Lead to Advances in Organic Spintronics July 1st, 2015

NIST ‘How-To’ Website Documents Procedures for Nano-EHS Research and Testing July 1st, 2015

Ultra-stable JILA microscopy technique tracks tiny objects for hours July 1st, 2015

Govt.-Legislation/Regulation/Funding/Policy

New technology using silver may hold key to electronics advances July 2nd, 2015

NIST Group Maps Distribution of Carbon Nanotubes in Composite Materials July 2nd, 2015

NIST ‘How-To’ Website Documents Procedures for Nano-EHS Research and Testing July 1st, 2015

Ultra-stable JILA microscopy technique tracks tiny objects for hours July 1st, 2015

Sensors

Groundbreaking research to help control liquids at micro and nano scales July 3rd, 2015

New micro-supercapacitor structure inspired by the intricate design of leaves: A team of scientists in Korea has devised a new method for making a graphene film for supercapacitors July 2nd, 2015

Carnegie Mellon chemists characterize 3-D macroporous hydrogels: Methods will allow researchers to develop new 'smart' materials June 30th, 2015

Visible Light-Sensitive Photocatalysts Used for Purification of Contaminated Water in Iran June 30th, 2015

Discoveries

Clues to inner atomic life from subtle light-emission shifts: Hyperfine structure of light absorption by short-lived cadmium atom isotopes reveals characteristics of the nucleus that matter for high precision detection methods July 3rd, 2015

Groundbreaking research to help control liquids at micro and nano scales July 3rd, 2015

Producing spin-entangled electrons July 2nd, 2015

NIST Group Maps Distribution of Carbon Nanotubes in Composite Materials July 2nd, 2015

Announcements

Clues to inner atomic life from subtle light-emission shifts: Hyperfine structure of light absorption by short-lived cadmium atom isotopes reveals characteristics of the nucleus that matter for high precision detection methods July 3rd, 2015

Pioneering Southampton scientist awarded prestigious physics medal July 3rd, 2015

Groundbreaking research to help control liquids at micro and nano scales July 3rd, 2015

NIST Group Maps Distribution of Carbon Nanotubes in Composite Materials July 2nd, 2015

Tools

Clues to inner atomic life from subtle light-emission shifts: Hyperfine structure of light absorption by short-lived cadmium atom isotopes reveals characteristics of the nucleus that matter for high precision detection methods July 3rd, 2015

Nanometrics to Announce Second Quarter Financial Results on July 23, 2015 July 2nd, 2015

NIST ‘How-To’ Website Documents Procedures for Nano-EHS Research and Testing July 1st, 2015

Ultra-stable JILA microscopy technique tracks tiny objects for hours July 1st, 2015

Research partnerships

Groundbreaking research to help control liquids at micro and nano scales July 3rd, 2015

Producing spin-entangled electrons July 2nd, 2015

Harris & Harris Group Portfolio Company, AgBiome, Announces Partnership to Accelerate the Discovery of Next Generation Insect-Resistant Crops July 1st, 2015

Leti Announces Launch of First European Nanomedicine Characterisation Laboratory: Project Combines Expertise of 9 Partners in 8 Countries to Foster Nanomedicine Innovation and Facilitate Regulatory Approval July 1st, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project