Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Engineers visualize electric memory as it fades

02.06.2004


While the memory inside electronic devices may often be more reliable than that of humans, it, too, can worsen over time.

Now a team of scientists from the University of Wisconsin-Madison and Argonne National Laboratory may understand why. The results are published in the early online edition (May 23) of the journal Nature Materials.

Smart cards, buzzers inside watches and even ultrasound machines all take advantage of ferroelectrics, a family of materials that can retain information, as well as transform electrical pulses into auditory or optical signals, or vice versa.



"The neat thing about these materials is that they have built-in electronic memory that doesn’t require any power," explains Paul Evans, a UW-Madison assistant professor of materials science and engineering, and a co-author of the recent paper.

But there’s a problem preventing many of these materials from being used more widely in other technologies, including computers. As Evans says, "Eventually they quit working."

The ability of ferroelectrics to store information resides in their arrangement of atoms, with each structure holding a bit of information. This information changes every time the material receives a pulse of electricity, basically switching the arrangement of atoms.

However, each electric pulse - and corresponding change in structure - gradually diminishes the capability of these materials to store and retrieve information until they either forget the information or quit switching altogether.

"It could switch 10,000 or even millions of times and then stop working," says Evans.

Engineers call this problem fatigue. With little evidence for what happens to the structure of ferroelectrics as the material’s memory fatigues, Evans and his colleagues decided to look inside this material as its arrangement of atoms, controlled by electrical pulses, switched inside an operating device.

"We’d like to understand how it switches so we could build something that switches faster and lasts longer before it wears out," says Evans.

To create a detailed picture of how the atoms rearrange themselves inside an operating device during each electrical pulse, the researchers used the Advanced Photon Source - the country’s most brilliant source of X-rays for research, located at the Argonne National Laboratory - to measure changes in the location of atoms. By seeing how the atoms changed their positions, the researchers could determine how well the material switched, or remembered information.

"One advantage to working with X-rays is their ability to penetrate deep into materials, which is why they are so extensively used today in medical imaging," says Eric Isaacs, director of Argonne’s Center for Nanoscale Materials, and one of the paper’s co-authors. "Utilizing this property of X-rays, [we] were able to peer through layers of metal electrodes in order to study ferroelectric fatigue in a realistic operating device."

He adds that the very high brightness of the Advanced Photon Source allowed the researchers to focus X-rays to unprecedented small dimensions.

The X-rays showed that, as the researchers repeatedly pulsed the device, progressively larger areas of the device ceased working, suggesting that the atoms were switching structures less and less.

"After 50,000 switches, the atoms were stuck - they couldn’t switch anymore," says Evans, adding that a stronger electrical charge did put the atoms back in motion.

When the researchers used a higher voltage of electricity from the beginning, switching stopped 100 times later, as reported in the paper. And, in this instance, applying an even stronger pulse made no difference.

"With higher voltages, the material can’t switch because something has changed about the material itself," says Evans. "When you use bigger voltages, it’s not just the switching that stops working, but something even more fundamental."

Because previous researchers have not peeked inside working ferroelectric materials to understand their arrangement of atoms - key to the ability to recall information - the reasons why switching eventually stops had not been clearly identified.

"The electronic memory is stored in the structure of atoms, and that’s why it’s so important to see what the structure looks like," explains Evans. By looking inside these devices, he says engineers can begin to understand why the atoms stop switching and then manufacturers can start to design better devices.

With this promise, Evans asks, "Wouldn’t it be nice to have a computer that doesn’t forget what it’s doing when you turn it off?"

Other researchers involved in the work include Chang Beom Eom, Dong Min Kim and the paper’s first author, Dal-Hyun Do, from UW-Madison; and Eric Dufresne, from the University of Michigan.
###
- Emily Carlson (608) 262-9772, emilycarlson@wisc.edu


Emily Carlson | University of Wisconsin
Further information:
http://www.news.wisc.edu/releases/9863.html

More articles from Power and Electrical Engineering:

nachricht Did you know that the wrapping of Easter eggs benefits from specialty light sources?
13.04.2017 | Heraeus Noblelight GmbH

nachricht To e-, or not to e-, the question for the exotic 'Si-III' phase of silicon
05.04.2017 | Carnegie Institution for Science

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>