Researchers at IISc improved efficacy of piezoelectric ceramic material

Researchers Rajeev Ranjan and Gobinda Das Adhikary at Indian Institute of Science (IISc) able to reduce the thickness of piezoceramics by preventing atomic defects inadvertently formed during manufacturing to increase efficacy of a commonly-used piezoelectric ceramic material. Here are more details shared in IISc release: Piezoelectric materials deform (stretch or contract) when an electric field is applied, making them suitable for wide-ranging applications, from ultrasound imaging in hospitals to actuators in guided missiles. Single crystals of some synthetic piezoelectrics show large longitudinal electrostrain (>1%), a value that indicates how much the material deforms in the direction of the field. But such materials are rare, and mass-producing single crystals is costly. They are therefore used only for niche applications. For most commercial applications, the more economical polycrystalline piezoelectric ceramics are used. However, these show much lower longitudinal strain (0.2-0.4%). “The maximum electrostrain reported in polycrystalline lead-free piezoelectrics is 0.7%,” says Gobinda Das Adhikary, first author and former PhD student at the Department of Materials Engineering (MatE), IISc. “Our intention was to increase the strain beyond this.” Every grain in a piezoceramic contains spontaneously polarised regions called domains that switch their orientation...