Scientists find simple ways to make piezoelectric materials more effective

BENGALURU: Scientists have discovered that making piezoelectric ceramics — used in a wide range of applications such as motion sensors, watches, ultrasonic power transducers, etc — thinner and preventing manufacturing defects can significantly improve their performance.
The breakthrough could lead to better

ultrasound machines

and other devices that rely on these materials.
A research team at the Indian Institute of Science (IISc) found that reducing the thickness of a common piezoelectric ceramic called PZT from 0.7mm to 0.2mm increased its ability to deform by more than three times.
“The maximum electrostrain reported in polycrystalline

lead-free piezoelectrics

is 0.7%,” says Gobinda Das Adhikary, the study’s lead author. “Our intention was to increase the strain beyond this.”

The team also identified a manufacturing issue that had been causing confusion in the field. When these materials are heated during production, they can develop defects called oxygen vacancies, IISc said, adding that these defects can cause the material to bend rather than stretch, leading to misleading measurements.
Prof Rajeev Ranjan, who led the research, suggests a practical solution: “By replacing a 1mm ceramic disc that has 0.3% strain with five 0.2mm discs stacked on top of each other, you can get a much higher strain.”
IISc said the findings are particularly important because they could help develop better lead-free

piezoelectric materials

. Current commercial versions often contain lead, which is toxic and environmentally harmful.
The research team has already made progress in this direction, claiming to have achieved even better results with a lead-free material, though these findings are yet to be published. The study was published in Nature and included collaboration with scientists at the European Synchrotron Radiation Facility (ESRF).