Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. Space Industry and Business News .




TECH SPACE
Bottom-up approach provides first characterization of pyroelectric nanomaterials
by Staff Writers
Chicago IL (SPX) Jan 11, 2013


File image.

By taking a "bottom-up" approach, researchers at the University of Illinois at Urbana-Champaign have observed for the first time that "size does matter" in regards "pyroelectricity"-the current/voltage developed in response to temperature fluctuations that enables technologies such as infrared sensors, night-vision, and energy conversion units, to name a few.

"Controlling and manipulating heat for applications such as waste heat energy harvesting, integrated cooling technologies, electron emission, and related functions is an exciting field of study today," explained Lane Martin, an assistant professor of materials science and engineering at Illinois.

"Traditionally, these systems have relied on bulk materials, but future nanoscale devices will increasingly require ferroelectric thin films.

"Measuring the pyroelectric response of thin films is difficult and has restricted the understanding of the physics of pyroelectricity, prompting some to label it as 'one of the least-known properties of solid materials'," Martin added.

"This work provides the most complete and detailed modeling and experimental study of this widely unknown region of materials and has direct implications for next generation devices."

Researchers found that reducing the dimensions of ferroelectrics increases their susceptibility to size- and strain-induced effects. The group's paper, "Effect of 90-degree domain walls and thermal expansion mismatch on the pyroelectric properties of epitaxial PbZr0.2Ti0.8O3 thin films," appears in the journal Physical Review Letters.

"What we did in this work was to develop a new approach to utilize and understand a class of materials important for all of these applications," Martin said.

"By moving to a 'bottom-up' approach that produces nanoscale versions of these materials as thin films, we have observed, for the first time, that certain features, namely domain walls, can be incredibly important and even dominate the temperature-dependent response and performance of these materials."

According to J. Karthik, the first author on the group's paper, thin-film epitaxy has been developed to provide a set of parameters (e.g., film composition, epitaxial strain, electrical boundary conditions, and thickness) that allow for precise control of ferroelectrics and has been instrumental in understanding the physics of dielectric and piezoelectric effects.

"We investigated the contribution of 90+ domain walls and thermal expansion mismatch to pyroelectricity in ferroelectric PbZr0.2Ti0.8O3 thin films, a widely used material whose bulk ferroelectric and piezoelectric properties are well understood," Karthik explained.

As part of this work, Martin's Prometheus research group developed and applied the first phenomenological models to include extrinsic and secondary contributions to pyroelectricity in polydomain films and predict significant extrinsic contributions (arising from the temperature-dependent motion of domain walls) and large secondary contributions (arising from thermal expansion mismatch between the film and the substrate).

"We have also developed and applied a new phase-sensitive pyroelectric current measurement process to measure thin films for the first time and reveal a dramatic increase in the pyroelectric coefficient with increasing fraction of in-plane oriented domains and thermal expansion mismatch consistent with these models," Karthik said.

"By establishing an understanding of the science of these effects, with models to predict their performance, and demonstrated techniques to fabricate and utilize these properties in nanoscale versions of these materials, their properties can be effectively integrated into existing electronics," Martin said.

This research was supported by the Office of Naval Research, the Army Research Office, and the Air Force Office of Scientific Research.

.


Related Links
University of Illinois College of Engineering
Space Technology News - Applications and Research






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





TECH SPACE
Chemical modules that mimic predator-prey and other behaviors
Washington DC (SPX) Jan 11, 2013
Scientists are reporting development of chemical modules that can reproduce, on an "unprecedented" molecular level, changes and interactions that occur in natural populations of plants and animals, including those of hunting and being hunted for food, conducting mutually beneficial relationships and competing for resources. The report on these new "predator-prey biochemical oscillators," w ... read more


TECH SPACE
Study reveals ordinary glass's extraordinary properties

Bottom-up approach provides first characterization of pyroelectric nanomaterials

Chemical modules that mimic predator-prey and other behaviors

Government funding for 'super-material'

TECH SPACE
TS Receives Funding For SNAP Deployable Satellite Systems Equipment

MUOS Waveform Will Improve Secure Communications Capabilities

DARPA selects SwRI's K-band space crosslink radio for flight development as part of System F6 Program

BAE pulls out of Australian comms tender

TECH SPACE
Roscosmos Releases Report On Proton Launch Anomaly

Russia plans replacement for Soyuz rocket

Arianespace's industry leadership will continue with 12 launcher family missions planned in 2013

Arianespace addresses The Insurance Institute of London

TECH SPACE
New location system could compete with GPS

Beidou's unique services attractive to Chinese companies

China eyes greater market share for its GPS rival

Researchers told to ward off navigation system interference

TECH SPACE
China-owned BOC Aviation says ordering 50 Airbus A320s

Taiwan expecting US-made Apaches: report

China approves second Beijing airport: state media

Turkey postpones order for its first two F-35 fighters

TECH SPACE
New biochip technology uses tiny whirlpools to corral microbes

Power spintronics: Producing AC voltages by manipulating magnetic fields

Researchers demonstrate record-setting p-type transistor

Marvell hit with billion-dollar verdict in patent case

TECH SPACE
Canada Launches Final Stage of RADARSAT Project

China no longer reliant on satellite image imports

TerraSAR-X image of the month - the coastal cliffs of Christmas Island

Joint Polar Satellite System Common Ground System now serving newest mission

TECH SPACE
China pollution anger spills into state media

Beijing choked by third day of hazardous smog

Italy extends emergency powers for Costa shipwreck

Pollution turns Hong Kong harbour from 'fragrant' to foul




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement