This image shows how the scientists used a synchrotron to discover that charge screening in lead zirconate titanate nanorods can control their domain pattern. The c-domain fraction markedly increased as the rod width decreased, while coating the nanorods with metal caused the a-domain fraction to increase. Image: Tomoaki Yamada.
This image shows how the scientists used a synchrotron to discover that charge screening in lead zirconate titanate nanorods can control their domain pattern. The c-domain fraction markedly increased as the rod width decreased, while coating the nanorods with metal caused the a-domain fraction to increase. Image: Tomoaki Yamada.

Many next-generation electronic and electro-mechanical device technologies hinge on the development of ferroelectric materials. The unusual crystal structures of these materials produce 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 polarization direction.

These crystals are typically grown on supporting substrates that help to define and organize the behavior of domains. Control over the switching of domains when making ferroelectric materials is essential for any future applications.

Now an international team led by scientists at Nagoya University in Japan has developed a new way of controlling the domain structure of ferroelectric materials, which could accelerate development of future electronic and electro-mechanical devices. They report their advance in a paper in Scientific Reports.

"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," explains lead author Tomoaki Yamada from Nagoya University. "The domain structure of the nanorods was almost completely flipped compared with [that of] the thin film."

Lead zirconate titanate is a common type of ferroelectric material, which switches based on the movement of trapped lead atoms between two stable positions in the crystal lattice. The scientists deliberately removed parts of the film to leave freestanding rods on the substrates and 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, compared with the thin film. This caused the domain properties to be influenced more by the surrounding environment, which modified the domain structure. The team found that coating the rods with a metal could screen the effects of the surrounding environment, causing the rods to recover the original domain structure, as dictated by the substrate.

"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 team member Nava Setter from Tel-Aviv University in Israel. "We have learned that it's possible to nanostructure these materials with control over their domains, which is an essential step towards the new functional nanoscale devices promised by these materials."

This story is adapted from material from Nagoya University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.