Shape-memory effect in twisted ferroic nanocomposites

The shape recovery ability of shape-memory alloys vanishes below a critical size (similar to 50nm), which prevents their practical applications at the nanoscale. In contrast, ferroic materials, even when scaled down to dimensions of a few nanometers, exhibit actuation strain through domain switching, though the generated strain is modest (similar to 1%). Here, we develop freestanding twisted architectures of nanoscale ferroic oxides showing shape-memory effect with a giant recoverable strain (>8%). The twisted geometrical design amplifies the strain generated during ferroelectric domain switching, which cannot be achieved in bulk ceramics or substrate-bonded thin films. The twisted ferroic nanocomposites allow us to overcome the size limitations in traditional shape-memory alloys and open new avenues in engineering large-stroke shape-memory materials for small-scale actuating devices such as nanorobots and artificial muscle fibrils.

Automated summary

By designing twisted architectures, we have developed freestanding nanoscale ferroic oxide structures that exhibit a giant recoverable strain (>8%) and shape-memory effect. This breakthrough overcomes the size limitations in traditional shape-memory alloys and paves the way for engineering small-scale actuating devices such as nanorobots and artificial muscle fibrils.