(Press-News.org) 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."
INFORMATION:
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.
Washington, D.C. (September 14, 2010) -- A new "on-chip" method for sorting and identifying bacteria has been created by biomedical engineers at Taiwan's National Cheng Kung University. The technique, developed by Hsien-Chang Chang, a professor at the Institute of Biomedical Engineering and the Institute of Nanotechnology and Microsystems Engineering, along with former graduate student I-Fang Cheng and their colleagues, is described in the AIP journal Biomicrofluidics.
Using roughened glass slides patterned with gold electrodes, the researchers created microchannels to ...
Washington, D.C. (September 14, 2010) -- Some disasters and crises are related to each other by more than just the common negative social value we assign to them. For example, earthquakes, homicide surges, magnetic storms, and the U.S. economic recession are all kindred of a sort, according to a theoretical framework presented in the journal CHAOS, which is published by the American Institute of Physics.
The researchers who developed this framework contend that these four types of events share a precursory development pattern -- a specific change of scale in indicators ...
Washington, D.C. (September 14, 2010) -- Because one of the main bottlenecks in determining the structure of protein molecules is producing good isolated single crystals, improved crystallization techniques would be useful in a wide range of genomics and pharmaceutical research.
Research reported in The Journal of Chemical Physics uses fluorescence correlation spectroscopy (FCS) to investigate the processes at the surface of a growing crystal. By focusing a laser on the crystal surface and measuring the resulting fluorescence, FCS can resolve dimensions as small as a ...
Leading international marine scientists are proposing radical changes in the governance of the world's oceans to rescue them from overfishing, pollution and other human impacts.
Based on a successful experiment in Chile, the researchers say a new approach to marine tenure could help to reverse the maritime 'tragedy of the commons' which has led to the depletion of fish stocks worldwide.
"Marine ecosystems are in decline around the world. New transformational changes in governance are urgently required to cope with overfishing, pollution, global changes, and other drivers ...
Tranquil living environments can positively affect the human brain function, according to researchers at the University of Sheffield.
The research, which was published in the journal NeuroImage, uses functional brain imaging to assess how the environment impacts upon our brain functions.
The findings demonstrated that tranquil environmental scenes containing natural features, such as the sea, cause distinct brain areas to become 'connected' with one another whilst man-made environments, such as motorways, disrupt the brain connections.
The research involved academics ...
INDIANAPOLIS – A new study led by Elizabeth Poposki, Ph.D., assistant professor of psychology in the School of Science at Indiana University-Purdue University Indianapolis, may help employers identify employees who enjoy multitasking and are less inclined to quit jobs involving multitasking. The study presents a new tool developed to measure preference for multitasking, information which may be of interest to bosses who tire of repeatedly hiring and training new employees.
A growing number of individuals must multitask at work and positions requiring a significant amount ...
A record-breaking 429 White-shouldered Ibis Pseudibis davisoni have just been recorded in Cambodia, making the known global population much larger than previously thought. With so many birds remaining in the wild the chances of conservation success are greatly improved – welcome news for this Critically Endangered bird species.
The University of East Anglia (UEA), UK, brought together a group of conservationists for a coordinated survey of 37 roost sites across Cambodia. Participants came from the Cambodian Forestry Administration and General Department for Administration ...
New research from North Carolina State University will help medical examiners and others identify human remains of those killed during the recent earthquake in Chile, as well as the bodies of the "disappeared" who were killed during the Pinochet administration.
"We have developed population-specific identification criteria for the Chilean population, which will help us determine the stature and biological sex of skeletal remains," says Dr. Ann Ross, an associate professor of sociology and anthropology at NC State and lead author of a paper describing the research.
"My ...
Hybrid cars and those fuelled by natural gas produce significantly less carbon dioxide (CO2) than equivalent vehicles running on gasoline. In the course of a study undertaken on behalf of the Swiss Federal Office for the Environment (FOEN), the results of which were recently published, Empa has investigated the CO2 emission behavior of current hybrid cars. A comparison with gasoline and natural gas fuelled vehicles concludes that hybrid vehicles are the cleanest during inner-city driving whilst natural gas fuelled cars do best on the motorway. When driven in rural areas, ...
Seamless fabric that can be sprayed on to skin and other surfaces to make clothes, medical bandages and even upholstery will be demonstrated this Thursday, in advance of the Science in Style spray-on fashion show next week at Imperial College London.
Dr Manel Torres is a Spanish fashion designer and academic visitor at Imperial, where he has collaborated with Paul Luckham, Professor of Particle Technology from the Department of Chemical Engineering, to create a seamless material called Fabrican Spray-on fabric that can be sprayed directly onto the body, using aerosol ...