Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ORNL research uncovers path to defect-free thin films

21.09.2012
A team led by Oak Ridge National Laboratory's Ho Nyung Lee has discovered a strain relaxation phenomenon in cobaltites that has eluded researchers for decades and may lead to advances in fuel cells, magnetic sensors and a host of energy-related materials.

The finding, published in Nano Letters, could change the conventional wisdom that accommodating the strain inherent during the formation of epitaxial thin films necessarily involves structural defects, said Lee, a member of the Department of Energy lab's Materials Science and Technology Division.


A schematic of a regular atomic array of ferromagnetic nano-domains formed due to an unconventional strain relaxation.

Instead, the researchers found that some materials, in this case cobaltite, form structurally well ordered atomic patterns that can change their magnetic properties and effectively minimize the size mismatch with the crystalline substrate.

Epitaxial thin films, used in nanotechnology and semiconductor fabrication, are created by growing a crystal layer of one material on another in such a way that the crystalline structures align. The challenge is to grow the film coherently with minimal defects, which can have a catastrophic effect on a material's performance.

"We discovered properties that were not readily apparent in crystal, or bulk, form, but in thin-film form we were able to clearly see the atomically ordered lattice structure of lanthanum cobaltite," Lee said. "With this knowledge, we hope to be able to tailor the physical properties of a material for many information and energy technologies."

The researchers studied the material in different strain states using scanning transmission electron microscopy complemented by X-ray and optical spectroscopy. Using these instruments, the scientists could see unconventional strain relaxation behavior that produced stripe-like lattice patterns. The result is a material with useful magnetic properties and highly suitable for sensors and ionic conductors used in, for example, batteries.

This discovery and the ability to engineer the structure of materials could lead to advanced cathode materials in solid oxide fuel cells and batteries that can be charged much faster.

"Since cobaltites are promising candidates for magnetic sensors, ionic conductors and surface catalysts, this discovery provides a new understanding that can be used for artificial tuning of magnetism and ionic activities," Lee said.

Contributing to the paper were ORNL's Woo Seok Choi and Hyoungjeen Jeen and authors from Seoul National University, the University of British Columbia, IFW Dresden's Leibniz Institute for Solid Sate and Materials Research, Max Planck-UBC Centre for Quantum Materials, Max Planck Institute for Solid State Research and the University of Saskatchewan.

The paper, titled "Strain-Induced Spin States in Atomically Ordered Cobaltites," is available at http://pubs.acs.org/doi/abs/10.1021/nl302562f. Funding for this work was provided primarily by the U.S. Department of Energy's Office of Science, Basic Energy Sciences. Optical measurements were performed in part at the Center for Nanophase Materials Sciences, a DOE-Basic Energy Sciences user facility.

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/.

UT-Battelle manages ORNL for the Office of Science. The 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 http://science.energy.gov/

Ron Walli | EurekAlert!
Further information:
http://science.energy.gov/
http://www.ornl.gov

More articles from Materials Sciences:

nachricht Physics, photosynthesis and solar cells
01.12.2016 | University of California - Riverside

nachricht New process produces hydrogen at much lower temperature
01.12.2016 | Waseda University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>