According the team, the crystal structures of ferroelectric materials have regions in their lattice, or domains, that behave like molecular switches.
The alignment of a domain can be toggled by an electric field, which changes the position of atoms in the crystal and switches the polarisation direction. These crystals are typically grown on supporting substrates that help to define and organise the behaviour of domains.
“We grew lead zirconate titanate films on different substrate types to induce different kinds of physical strain, and then selectively etched parts of the films to create nanorods,” said lead author Tomoaki Yamada.
The team then used synchrotron X-ray radiation to probe the domain structure of individual rods.
The contact area of the rods with the substrate was greatly reduced which meant domain properties and structure were influenced by the surrounding environment. The researchers found that coating the rods with a metal could screen the effects of the air and that they tended to recover the original domain structure.
“There are few effective ways of manipulating the domain structure of ferroelectric materials, and this becomes more difficult when the material is nanostructured and the contact area with the substrate is small.” says collaborator Nava Setter.
“We have learned that it’s possible to nanostructure these materials with control over their domains, which is an essential step towards new electronic and electro-mechanical nanoscale devices.”