Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

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

News and information

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

Sirrus's Issued Patent Portfolio Continues To Accelerate July 18th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Laboratories

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

Carbon is the new black: Researchers use carbon nanotubes to develop clothing that can double as batteries July 10th, 2018

NIST Researchers Simulate Simple Logic for Nanofluidic Computing June 30th, 2018

Cleaning or Etching Items with Unique Geometries Requires Specialized Expertise June 27th, 2018

Imaging

Oxford Instrumentsí 22 Tesla superconducting magnet system commissioned at the UAM, making it the most intense magnetic field available outside a large international facility July 12th, 2018

Govt.-Legislation/Regulation/Funding/Policy

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits July 16th, 2018

Sensors

Leti & Partners Launch Pilot Program to Assess New Perception Sensors for Autonomous Vehicles July 5th, 2018

New sensor technology enables super-sensitive live monitoring of human biomolecules July 3rd, 2018

A refined magnetic sense: Algorithms and hardware developed in the context of quantum computation are shown to be useful for quantum-enhanced sensing of magnetic fields July 2nd, 2018

NIST Researchers Simulate Simple Logic for Nanofluidic Computing June 30th, 2018

Discoveries

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits July 16th, 2018

Announcements

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

Sirrus's Issued Patent Portfolio Continues To Accelerate July 18th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Tools

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

Oxford Instrumentsí 22 Tesla superconducting magnet system commissioned at the UAM, making it the most intense magnetic field available outside a large international facility July 12th, 2018

Nanometrics to Announce Second Quarter Financial Results on July 31, 2018 July 12th, 2018

Nanometrics to Participate in the 10th Annual CEO Investor Summit 2018: Accredited investor and publishing research analyst event held concurrently with SEMICON West and Intersolar 2018 in San Francisco June 28th, 2018

Research partnerships

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication July 13th, 2018

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



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project