Subscribe free to our newsletters via your
. 24/7 Space News .




TECH SPACE
New Nano-sized Particles Could Provide Mega-sized Data Storage
by Staff Writers
Berkeley CA (SPX) Sep 23, 2010


This schematic shows enthalpy curves sketched for the liquid, crystalline and amorphous phases of a new class of nanomaterials called "BEANs" for Binary Eutectic-Alloy Nanostructures. (Image courtesy of Daryl Chrzan)

The ability of phase-change materials to readily and swiftly transition between different phases has made them valuable as a low-power source of non-volatile or "flash" memory and data storage. Now an entire new class of phase-change materials has been discovered by researchers with the Lawrence Berkeley National Laboratory and the University of California Berkeley that could be applied to phase change random access memory (PCM) technologies and possibly optical data storage as well.

The new phase-change materials - nanocrystal alloys of a metal and semiconductor - are called "BEANs," for binary eutectic-alloy nanostructures.

"Phase changes in BEANs, switching them from crystalline to amorphous and back to crystalline states, can be induced in a matter of nanoseconds by electrical current, laser light or a combination of both," says Daryl Chrzan, a physicist who holds joint appointments with Berkeley Lab's Materials Sciences Division and UC Berkeley's Department of Materials Science and Engineering.

"Working with germanium tin nanoparticles embedded in silica as our initial BEANs, we were able to stabilize both the solid and amorphous phases and could tune the kinetics of switching between the two simply by altering the composition."

Chrzan is the corresponding author on a paper reporting the results of this research which has been published in the journal NanoLetters titled "Embedded Binary Eutectic Alloy Nanostructures: A New Class of Phase Change Materials."

Co-authoring the paper with Chrzan were Swanee Shin, Julian Guzman, Chun-Wei Yuan, Christopher Liao, Cosima Boswell-Koller, Peter Stone, Oscar Dubon, Andrew Minor, Masashi Watanabe, Jeffrey Beeman, Kin Yu, Joel Ager and Eugene Haller.

"What we have shown is that binary eutectic alloy nanostructures, such as quantum dots and nanowires, can serve as phase change materials," Chrzan says.

"The key to the behavior we observed is the embedding of nanostructures within a matrix of nanoscale volumes. The presence of this nanostructure/matrix interface makes possible a rapid cooling that stabilizes the amorphous phase, and also enables us to tune the phase-change material's transformation kinetics."

A eutectic alloy is a metallic material that melts at the lowest possible temperature for its mix of constituents. The germanium tin compound is a eutectic alloy that has been considered by the investigators as a prototypical phase-change material because it can exist at room temperature in either a stable crystalline state or a metastable amorphous state.

Chrzan and his colleagues found that when germanium tin nanocrystals were embedded within amorphous silica the nanocrystals formed a bilobed nanostructure that was half crystalline metallic and half crystalline semiconductor.

"Rapid cooling following pulsed laser melting stabilizes a metastable, amorphous, compositionally mixed phase state at room temperature, while moderate heating followed by slower cooling returns the nanocrystals to their initial bilobed crystalline state," Chrzan says.

"The silica acts as a small and very clean test tube that confines the nanostructures so that the properties of the BEAN/silica interface are able to dictate the unique phase-change properties."

While they have not yet directly characterized the electronic transport properties of the bilobed and amorphous BEAN structures, from studies on related systems Chrzan and his colleagues expect that the transport as well as the optical properties of these two structures will be substantially different and that these difference will be tunable through composition alterations.

"In the amorphous alloyed state, we expect the BEAN to display normal, metallic conductivity," Chrzan says. "In the bilobed state, the BEAN will include one or more Schottky barriers that can be made to function as a diode. For purposes of data storage, the metallic conduction could signify a zero and a Schottky barrier could signify a one."

Chrzan and his colleagues are now investigating whether BEANs can sustain repeated phase-changes and whether the switching back and forth between the bilobed and amorphous structures can be incorporated into a wire geometry. They also want to model the flow of energy in the system and then use this modeling to tailor the light/current pulses for optimum phase-change properties.

The in-situ Transmission electron microscopy characterizations of the BEAN structures were carried out at Berkeley Lab's National Center for Electron Microscopy, one of the world's premier centers for electron microscopy and microcharacterization.

.


Related Links
National Center for Electron Microscopy
Chrzan Lab at Berkeley
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
Satisfaction with computers at all-time high in US
San Francisco (AFP) Sept 21, 2010
US computer buyers are happy as ever, with Apple machines yielding top satisfaction and Windows 7 operating system making amends for a loathed prior generation of the Microsoft software. Annual figures released on Tuesday by The American Customer Satisfaction Index showed a four-percent improvement in the way people felt about their computers, with Apple leading the way by pleasing 86 percen ... read more


TECH SPACE
Watch Out For The Super Harvest Moon

Water on Moon is bad news for China's lunar telescope

New Insights Into The Moon's Rich Geologic Complexity

Astrium Investigates Automatic Landing At The Moon's South Pole

TECH SPACE
NASA tests (cramped) Mars-type rovers in Arizona desert

Team Restoring Mars Orbiter After Reboot

Strong Robotic Arm Extends From Next Mars Rover

105 Days In Isolation - And Counting - For 400 More

TECH SPACE
Desert RATS In The Field

Data Clippers Set Sail To Enhance Future Planetary Missions

XCOR Completes Lynx Supersonic Wind Tunnel Tests

Finalist For NASA Space Mission Just Got More Interesting

TECH SPACE
Space-Age Device To Deliver More Efficient Health Care On Earth And Above

China Launches New Satellite

China's Second Lunar Probe Chang'e-2 To Reach Lunar Orbit Faster Than Chang'e-1

China Finishes Construction Of First Unmanned Space Module

TECH SPACE
Departure Preps And Handover Activities For ISS Crew

ISS Departure Preparations

Russian Mission Control Set To Readjust ISS Orbit

Boeing wins billion dollar NASA extension

TECH SPACE
LockMart And ATK Athena Launch Vehicles Selected As A NASA Launch Services Provider

Sirius XM-5 Satellite Delivered To Baikonur For October Launch

Emerging Technologies May Fuel Revolutionary Launcher

EUMETSAT Chooses Arianespace To Launch Metop-C

TECH SPACE
This Planet Smells Funny

Scientists looking to spot alien oceans

Deadly Tides Mean Early Exit For Hot Jupiters

Can We Spot Volcanoes On Alien Worlds

TECH SPACE
Newspaper publishers want control over iPad subscriptions

Thales Alenia Space To Supply Components For Russian Satellites

BlackBerry tablet computer poised for debut: WSJ

New Nano-sized Particles Could Provide Mega-sized Data Storage




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