Monday, October 23, 2000
Understanding stress in piezoelectric thin films is key to their
design and optimization as smart materials, according to Nancy Scottos, a
professor of theoretical and applied mechanics at the University of Illinois
(Urbana, IL). She observed that the thinner ceramic films become, the smaller
their piezoelectric responses become.
Scottos and other researchers at the University of Illinois are
studying how stress builds up in piezoelectric thin films during their
fabrication process. "Shrinkage and densification during the drying and firing
processes cause stress," she says.
Scottos exposed thin films to varying amounts of mechanical
stress. By applying a small mechanical load in the opposite direction to the
tensile strength, they were able to relieve residual stress on the film.
Relieving the stress made the film's piezoelectric response 10 to 30%
For more information, write to the University of Illinois, Talbot
Lab, 104 S. Wright St., Urbana, IL 61801.