MADISON Integrating a complex, single-crystal material with "giant" piezoelectric properties onto silicon, University of Wisconsin-Madison engineers and physicists can fabricate low-voltage, near-nanoscale electromechanical devices that could lead to improvements in high-resolution 3-D imaging, signal processing, communications, energy harvesting, sensing, and actuators for nanopositioning devices, among others.
Led by Chang-Beom Eom, a UW-Madison professor of materials science and engineering and physics, the multi-institutional team published its results in the Nov. 18, issue of the journal Science. (Eom and his students also are co-authors on another paper, "Domain dynamics during ferroelectric switching," published in the same issue.)
Piezoelectric materials use mechanical motion to generate an electrical signal, such as the light that flashes in some children's shoe heels when they stomp their feet. Conversely, piezoelectrics also can use an electrical signal to generate mechanical motionfor example, piezoelectric materials are used to generate high-frequency acoustic waves for ultrasound imaging.
Eom studies the advanced piezoelectric material lead magnesium niobate-lead titanate, or PMN-PT. Such materials exhibit a "giant" piezoelectric response that can deliver much greater mechanical displacement with the same amount of electric field as traditional piezoelectric materials. They also can act as both actuators and sensors. For example, they use electricity to deliver an ultrasound wave that penetrates deeply into the body and returns data capable of displaying a high-quality 3-D image.
Currently, a major limitation of these advanced materials is that to incorporate them into very small-scale devices, researchers start with a bulk material and grind, cut and polish it to the size they desire. It's an imprecise, error-prone process that's intrinsically ill-suited for nanoelectromechanical systems (NEMS) or micr
|Contact: Chang-Beom Eom|
University of Wisconsin-Madison