Lead zirconate titanate ceramics are the "gold standard" materials for transducers, actuators and other applications of ferroelectric ceramic materials. Unfortunately, lead is toxic, and there is an ongoing effort to find a lead-free alternative with strong piezoelectric properties, driven at least in part by the EU RoHS regulations. Finding suitable substitute materials has proved challenging, enough so that the EU has issued a RoHS exemption, which allows PZT to continue to be used. Although it is a reprieve, there is a growing body of work to find lead-free ferroelectric materials. A challenge facing researchers is to understand the mechanisms by which the piezoelectric property develops in lead-free ferroelectrics. A new paper in Physical Review Letters reports on a major breakthrough in understanding the mechanisms by which the piezoelectric property is included in lead-free BNT-BT piezoelectric ceramics, is described in this article.
