Swift walls

Adv. Mater. http://doi.org/f2x83m (2015)

Ferroelectric materials consist of domains of aligned electric dipoles, separated by domain walls. When an electric field is applied the various domains can reorient, leading to a switching in net polarization of the bulk material. This process requires the nucleation and growth of the domain walls however, associated with which will be a time delay. Given that ferroelectric materials are being utilized in applications that rely on this switching process, such as fast, high-density, non-volatile memory, it is vital that changes in domain structure occur quickly, necessitating fast domain wall kinetics. Er-Jia Guo and co-workers now demonstrate that a small in-plane epitaxial strain is effective at enhancing domain wall velocity; approximately 0.1% in-plane strain in ferroelectric PbZr_0.2Ti_0.8O₃ grown on an La_0.7Sr_0.3MnO₃ substrate can drive an order of magnitude increase in the velocity of 180° domain walls. This study demonstrates that by understanding and controlling external parameters it may be possible to optimize fast switching between polarization states in ferroelectrics.