Faster ferroelectric switching

MIT Technology Review : Ferroelectric materials can be made to reverse the direction of their polarization by applying an electric field. Once changed, the direction of the polarization persists, a property that has been exploited to store data. But until now, the speed at which the change occurs has been too low to rival the switching speeds attained by silicon-based transistors. A collaboration led by Lane Martin of the University of California, Berkeley, and Andrew Rappe of the University of Pennsylvania has developed a ferroelectric material, lead zirconate titanate (PbZr_0.2Ti_0.8O₃), that can switch much faster than standard ferroelectrics. The key to the gain in speed lies in growing crystals of the material at a particular orientation, which creates two so-called side states of polarization in addition to the regular two states. The faster-switching side states can be manipulated by applying an electric field in a particular direction.