Some swell materials give up their secret

Piezoelectric materials change their size in response to electricity and produce an electric signal in response to pressure. Some of these substances, which play roles in sonar equipment, ultrasonic scanners, ink-jet printer heads, and other devices, are much more responsive than others. Now scientists may have identified the specific atomic arrangement, or phase, that underlies the behavior of the best piezoelectric substances, a find that could lead to even better materials.