Highly Flexible Freestanding BaTiO<sub>3</sub>‐CoFe<sub>2</sub>O<sub>4</sub> Heteroepitaxial Nanostructure Self‐Assembled with Room‐Temperature Multiferroicity
Gaokuo Zhong, Feng An, Ke Qu, Yongqi Dong, Zhenzhong Yang, Liyufen Dai, Shuhong Xie, Rong Huang, Zhenlin Luo, Jiangyu Li
Abstract
Abstract Multiferroics with simultaneous electric and magnetic orderings are highly desirable for sensing, actuation, data storage, and bio‐inspired systems, yet developing flexible materials with robust multiferroic properties at room temperature is a long‐term challenge. Utilizing water‐soluble Sr 3 Al 2 O 6 as a sacrificial layer, the authors have successfully self‐assembled a freestanding BaTiO 3 ‐CoFe 2 O 4 heteroepitaxial nanostructure via pulse laser deposition, and confirmed its epitaxial growth in both out‐of‐plane and in‐plane directions, with highly ordered CoFe 2 O 4 nanopillars embedded in a single crystalline BaTiO 3 matrix free of substrate constraint. The freestanding nanostructure enjoys super flexibility and mechanical integrity, not only capable of spontaneously curving into a roll, but can also be bent with a radius as small as 4.23 µm. Moreover, piezoelectricity and ferromagnetism are demonstrated at both microscopic and macroscopic scales, confirming its robust multiferroicity at room temperature. This work establishes an effective route for flexible multiferroic materials, which have the potential for various practical applications.