[ Back to EurekAlert! ] Public release date: 14-Sep-2010
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Contact: Jason Socrates Bardi
jbardi@aip.org
301-209-3091
American Institute of Physics

Lead-free piezoelectric materials of the future

Washington, D.C. (September 14, 2010) -- Piezoelectric materials have fantastic properties: squeeze them and they generate an electrical field. And vice-versa, they contract or expand when jolted with an electrical pulse. With a name derived from the Greek word meaning to squeeze or press, the piezoelectric effect was just a curiosity after it was discovered in several crystals in 1880. But in 1917, a quartz piezoelectric crystal was at the heart of the world's first submarine-detecting sonar.

Piezoelectric materials really took off after the 1950s, with the development of a superior man-made piezoelectric ceramic crystal: lead zirconate titanate, or PZT (the initials of its chemical symbols). Over the past 60 years, PZT has been essential for myriad high-tech applications: from inkjet printers to digital camera shutters, ultrasonic imagers, fuel injector actuators, and igniters for gas barbecue grills.

Despite this success, many scientists now want to replace PZT with some as yet undiscovered lead-free material that would be more environmentally benign and that would enable new piezoelectric applications in biological settings. To date, however, no suitable successors have been found. Candidates are typically too feeble in their piezoelectric effect and/or physical durability.

A Swiss scientist, Dragan Damjanovic, thinks researchers should be looking more broadly. He says nearly all of today's efforts are focused on materials whose ions and electrons -- the ultimate source of the piezoelectric effect -- behave in a particular manner, called polarization rotation. His theoretical calculations have shown that another, overlooked behavior polarization extension, present in other classes of materials -- can also generate an enhanced piezoelectric effect.

An article by Damjanovic in the journal Applied Physics Letters, which is published by the American Institute of Physics, details his ideas and supporting evidence. In particular, he proposes a particular type of phase diagram that he believes will lead to improved, lead-free piezoelectric materials.

"What I have done is at odds with the dominant thinking," Damjanovic admits. "But I offer a different approach to an important problem."

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The article, "A morphotropic phase boundary system based on polarization rotation and polarization extension" by Dragan Damjanovic appears in the journal Applied Physics Letters. See: http://link.aip.org/link/applab/v97/i6/p062906/s1

Journalists may request a free PDF of this article by contacting jbardi@aip.org

Funding: from the Swiss National Research Program on Smart Materials (PNR 62, Contract No. 406240-126091).

ABOUT APPLIED PHYSICS LETTERS

Applied Physics Letters, published by the American Institute of Physics, features concise, up-to-date reports on significant new findings in applied physics. Emphasizing rapid dissemination of key data and new physical insights, Applied Physics Letters offers prompt publication of new experimental and theoretical papers bearing on applications of physics phenomena to all branches of science, engineering, and modern technology. Content is published online daily, collected into weekly online and printed issues (52 issues per year). See: http://apl.aip.org/

ABOUT AIP

The American Institute of Physics is a federation of 10 physical science societies representing more than 135,000 scientists, engineers, and educators and is one of the world's largest publishers of scientific information in the physical sciences. Offering partnership solutions for scientific societies and for similar organizations in science and engineering, AIP is a leader in the field of electronic publishing of scholarly journals. AIP publishes 12 journals (some of which are the most highly cited in their respective fields), two magazines, including its flagship publication Physics Today; and the AIP Conference Proceedings series. Its online publishing platform Scitation hosts nearly two million articles from more than 185 scholarly journals and other publications of 28 learned society publishers.



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