Featured Research

from universities, journals, and other organizations

Piezoelectrics and butterflies: Now scientists know more about how the materials actually work

Date:
January 30, 2014
Source:
National Institute of Standards and Technology (NIST)
Summary:
Piezoelectrics, materials that can change mechanical stress to electricity and back again, are everywhere in modern life. Computer hard drives. Loudspeakers. Medical ultrasound. Sonar. But there are major gaps in our understanding of how they work. Now researchers believe they've learned why one of the main classes of these materials, known as relaxors, behaves in distinctly different ways from the rest. The discovery comes in the shape of a butterfly.

These two neutron scattering images represent the nanoscale structures of single crystals of PMN and PZT. Because the atoms in PMN deviate slightly from their ideal positions, diffuse scattering results in a distinctive "butterfly" shape quite different from that of PZT, in which the atoms are more regularly spaced.
Credit: NIST

Piezoelectrics -- materials that can change mechanical stress to electricity and back again -- are everywhere in modern life. Computer hard drives. Loud speakers. Medical ultrasound. Sonar. Though piezoelectrics are a widely used technology, there are major gaps in our understanding of how they work. Now researchers at the National Institute of Standards and Technology (NIST) and Canada's Simon Fraser University believe they've learned why one of the main classes of these materials, known as relaxors, behaves in distinctly different ways from the rest and exhibit the largest piezoelectric effect. And the discovery comes in the shape of a butterfly.

Related Articles


The team examined two of the most commonly used piezoelectric compounds -- the ferroelectric PZT and the relaxor PMN -- which look very similar on a microscopic scale. Both are crystalline materials composed of cube-shaped unit cells (the basic building blocks of all crystals) that contain one lead atom and three oxygen atoms. The essential difference is found at the centers of the cells: in PZT these are randomly occupied by either one zirconium atom or one titanium atom, both of which have the same electric charge, but in PMN one finds either niobium or manganese, which have very different electric charges. The differently charged atoms produce strong electric fields that vary randomly from one unit cell to another in PMN and other relaxors, a situation absent in PZT.

"PMN-based relaxors and ferroelectric PZT have been known for decades, but it has been difficult to identify conclusively the origin of the behavioral differences between them because it has been impossible to grow sufficiently large single crystals of PZT," says the NIST Center for Neutron Research (NCNR)'s Peter Gehring. "We've wanted a fundamental explanation of why relaxors exhibit the greatest piezoelectric effect for a long time because this would help guide efforts to optimize this technologically valuable property."

A few years ago, scientists from Simon Fraser University found a way to make crystals of PZT large enough that PZT and PMN crystals could be examined with a single tool for the first time, permitting the first apples-to-apples comparison of relaxors and ferroelectrics. That tool was the NCNR's neutron beams, which revealed new details about where the atoms in the unit cells were located. In PZT, the atoms sat more or less right where they were expected, but in the PMN, their locations deviated from their expected positions -- a finding Gehring says could explain the essentials of relaxor behavior.

"The neutron beams scatter off the PMN crystals in a shape that resembles a butterfly," Gehring says. "It gives a characteristic blurriness that reveals the nanoscale structure that exists in PMN -- and in all other relaxors studied with this method as well -- but does not exist in PZT. It's our belief that this butterfly-shaped scattering might be a characteristic signature of relaxors."

Additional tests the team performed showed that PMN-based relaxors are over 100 percent more sensitive to mechanical stimulation compared to PZT, another first-time measurement. Gehring says he hopes the findings will help materials scientists do more to optimize the behavior of piezoelectrics generally.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology (NIST). Note: Materials may be edited for content and length.


Journal Reference:

  1. D. Phelan, C. Stock, J. A. Rodriguez-Rivera, S. Chi, J. Leao, X. Long, Y. Xie, A. A. Bokov, Z.-G. Ye, P. Ganesh, P. M. Gehring. Role of random electric fields in relaxors. Proceedings of the National Academy of Sciences, 2014; DOI: 10.1073/pnas.1314780111

Cite This Page:

National Institute of Standards and Technology (NIST). "Piezoelectrics and butterflies: Now scientists know more about how the materials actually work." ScienceDaily. ScienceDaily, 30 January 2014. <www.sciencedaily.com/releases/2014/01/140130133124.htm>.
National Institute of Standards and Technology (NIST). (2014, January 30). Piezoelectrics and butterflies: Now scientists know more about how the materials actually work. ScienceDaily. Retrieved March 5, 2015 from www.sciencedaily.com/releases/2014/01/140130133124.htm
National Institute of Standards and Technology (NIST). "Piezoelectrics and butterflies: Now scientists know more about how the materials actually work." ScienceDaily. www.sciencedaily.com/releases/2014/01/140130133124.htm (accessed March 5, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Thursday, March 5, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Did the Simpsons Figure out the Higgs Boson Particle Years Before Scientists

Did the Simpsons Figure out the Higgs Boson Particle Years Before Scientists

Buzz60 (Mar. 4, 2015) During a 1998 Simpsons episode, Homer Simpson scribbled a seemingly gibberish equation on a chalkboard. Turns out that equation is a shake off from predicting the actual nano mass of the God Particle. Patrick Jones (@Patrick_E_Jones) explains. Video provided by Buzz60
Powered by NewsLook.com
Wearables Now the Must-Haveables

Wearables Now the Must-Haveables

Reuters - Business Video Online (Mar. 3, 2015) Telecom company executives are meeting in Barcelona for the Mobile World Congress, the largest annual trade show for the wireless industry. As Ivor Bennett reports from the show wearable technology is one of the big themes. Video provided by Reuters
Powered by NewsLook.com
Forensic Holodeck Creates 3D Crime Scenes

Forensic Holodeck Creates 3D Crime Scenes

Reuters - Innovations Video Online (Mar. 3, 2015) A holodeck is no longer the preserve of TV sci-fi classic Star Trek, thanks to researchers from the Institute of Forensic Medicine Zurich, who have created what they say is the first system in the world to visualise the 3D data of forensic scans. Jim Drury saw it in operation. Video provided by Reuters
Powered by NewsLook.com
Solar Plane Passes New Test Ahead of World Tour

Solar Plane Passes New Test Ahead of World Tour

AFP (Mar. 2, 2015) A solar-powered plane made a third successful test flight in the United Arab Emirates on Monday ahead of a planned round-the-world tour to promote alternative energy. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins