Researchers at Aalto University developed a new material that changes its electrical behavior based on previous experience—gaining a form of adaptive memory. Scientists could use these materials in next-gen medical and environmental sensors, soft robots, or active surfaces.
Responsive materials are common, but their response to change doesn’t depend on their history, nor do they adapt based on their past.
In a quest to develop a material that could adjust its behavior based on its history, the researchers synthesized micrometer-sized magnetic beads and stimulated them with a magnetic field. When exposed to a magnetic field, the beads stack to form pillars. The strength of the magnetic field affects the shape of the pillars and how well they conduct electricity.
They found that the electrical conductivity of the pillars depended on whether they had varied the magnetic field rapidly or slowly or increased or decreased. The response showed bistability, relying on the history of the magnetic field—an elementary form of memory.