Researchers from the University of California Berkeley and the University of Pennsylvania have discovered a fundamentally new and unexpected way for these ferroelectric materials to respond to applied electric fields. Ferroelectric materials have spontaneous polarization as a result of small shifts of negative and positive charges within the material. The polarization can be reversed in response to an electric field, enabling the creation of a “0” or “1” data bit for memory applications. The discovery opens up the possibility for faster switching and new control over novel multi-state devices. The bits in a ferroelectric memory device depend on the position of metal atoms in the middle of six-pointed “cages” of oxygen atoms. The researchers took a thin film of lead zirconate titanate, a ferroelectric material, and found that by applying the electric field so that it wasn’t parallel to the up-down axis, they could change the polarization reorientation pathway. Adjusting how the ferroelectric film was confined and stretched enhanced the effect, leading to at least a doubling of the operational speed for the system.
