Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Conducting ferroelectrics may be key to new electronic memory

26.04.2011
Novel properties of ferroelectric materials discovered at the Department of Energy's Oak Ridge National Laboratory are moving scientists one step closer to realizing a new paradigm of electronic memory storage.

A new study led by ORNL's Peter Maksymovych and published in the American Chemical Society's Nano Letters revealed that contrary to previous assumptions, domain walls in ferroelectric materials act as dynamic conductors instead of static ones.

Domain walls, the separation zones only a few atoms wide between opposing states of polarization in ferroelectric materials, are known to be conducting, but the origin of the conductivity has remained unclear.

"Our measurements identified that subtle and microscopically reversible distortions or kinks in the domain wall are at the heart of the dynamic conductivity," Maksymovych said. "The domain wall in its equilibrium state is not a true conductor like a rigid piece of copper wire. When you start to distort it by applying an electric field, it becomes a much better conductor."

Ferroelectrics, a unique class of materials that respond to the application of an electric field by microscopically switching their polarization, are already used in applications including sonar, medical imaging, fuel injectors and many types of sensors.

Now, researchers want to push the boundaries of ferroelectrics by making use of the materials' properties in areas such as memory storage and nanoelectronics. Gaining a detailed understanding of electrical conductance in domain walls is seen as a crucial step toward these next generation applications.

"This study shows for the first time that the dynamics of these defects - the domain walls - are a much richer source of memory functionality," Maksymovych said. "It turns out you can dial in the level of the conductivity in the domain wall, making it a tunable, metastable, dynamic memory element."

The domain wall's tunable nature refers to its delayed response to changes in conductivity, where shutting off an electric field does not produce an immediate drop in conductance. Instead, the domain wall "remembers" the last level of conductance for a given period of time and then relaxes to its original state, a phenomenon known as memristance. This type of behavior is unlike traditional electronics, which rely on silicon transistors that act as on-off switches when electric fields are applied.

"Finding functionality intrinsic to nanoscale systems that can be controlled in a novel way is not a path to compete with silicon, but it suggests a viable alternative to silicon for a new paradigm in electronics," Maksymovych said.

The ORNL-led team focused on bismuth ferrite samples, but researchers expect that the observed properties of domain walls will hold true for similar materials.

"The resulting memristive-like behavior is likely to be general to ferroelectric domain walls in semiconducting ferroelectric and multiferroic materials," said ORNL co-author Sergei Kalinin.

The samples used in the study were provided by the University of California at Berkeley. Other authors are ORNL's Arthur Baddorf, Jan Seidel and Ramamoorthy Ramesh of Lawrence Berkeley National Laboratory and UC Berkeley, and Pennsylvania State University's Pingping Wu and Long-Qing Chen.

Part of this work was supported by the Center for Nanophase Materials Sciences at ORNL. CNMS is one of the five DOE Nanoscale Science Research Centers supported by the DOE Office of Science, premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE's Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos national laboratories. For more information about the DOE NSRCs, please visit http://science.energy.gov/bes/suf/user-facilities/nanoscale-science-research-centers/. Work at Lawrence Berkeley National Laboratory and the University of California, Berkeley, was supported by DOE's Office of Science and the Semiconductor Research Corporation.

ORNL is managed by UT-Battelle for the Department of Energy's Office of Science.

Morgan McCorkle | EurekAlert!
Further information:
http://www.ornl.gov

More articles from Power and Electrical Engineering:

nachricht Multicrystalline Silicon Solar Cell with 21.9 % Efficiency: Fraunhofer ISE Again Holds World Record
20.02.2017 | Fraunhofer-Institut für Solare Energiesysteme ISE

nachricht Six-legged robots faster than nature-inspired gait
17.02.2017 | Ecole Polytechnique Fédérale de Lausanne

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>