'Self-tuning' film paves the way for future wireless and radar devices

A research team from Queen Mary University of London has discovered a new way to engineer thin films that can "tune" themselves much more effectively than existing materials, making them highly responsive and efficient.

Ferroelectric films are used in modern communications and sensing systems, such as 5G, 6G, radar, and medical imaging. They need to adapt quickly to changing signals and frequencies. Until now, scientists have faced a tradeoff between making materials highly tunable and keeping them energy-efficient, but this new approach breaks that trade-off by making the material adaptable without wasting energy.

The work is published in the journal Nature Communications.

In tests, the new material, co-developed by Dr. Hanchi Ruan, Dr. Hangfeng Zhang, and other researchers, showed an unusually high level of "tunability." Its ability to change how it behaves reached about 74% at microwave frequencies. The team was surprised to find they only needed to apply a low voltage to achieve this, where normally, such performance would require much more energy or would cause significant energy losses.

Dr. Haixue Yan, Reader at School of Engineering and Materials Science at Queen Mary University of London, said, "The key to our method is the creation of tiny nanoclusters—small groups of atoms, far smaller than a human hair—inside the material.

"Normally, in barium titanate, atoms sit in a perfectly regular arrangement, like seats in a neatly packed stadium. By carefully swapping a small number of titanium atoms with tin, we disturb that perfect order and form tiny, irregular pockets where the atoms are slightly out of place. These nanoclusters move more easily when an electrical signal is applied, which makes the whole material much more responsive."

Professor Yang Hao, QinetiQ/Royal Academy of Engineering Research chair and Professor of Antennas and Electromagnetics at Queen Mary, who led this research, said, "This work could lead to the next generation of smaller, faster, and more energy-efficient wireless and radar devices. Phones could connect more reliably, satellites could communicate more clearly, and medical scanners could deliver sharper images.

"More broadly, the method of engineering nanoclusters through atomic substitution could inspire advances in many technologies, from sensors and defense systems to future quantum devices."