Shape-memory effect in twisted ferroic nanocomposites
Donghoon Kim, Min‐Soo Kim, Steffen Reidt, Hyeon Han, A. Baghizadeh, Peng Zeng, Hongsoo Choi, Josep Puigmartí‐Luis, Morgan Trassin, Bradley J. Nelson, Xiangzhong Chen, Salvador Pané
Abstract
The shape recovery ability of shape-memory alloys vanishes below a critical size (~50 nm), 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 (~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.