Self‐Assembled Epitaxial Ferroelectric Oxide Nanospring with Super‐Scalability

• Published in: Advanced materials (Weinheim) 2022-04, Vol.34 (13), p.e2108419-n/a
• Main Authors: Dong, Guohua, Hu, Yue, Guo, Changqing, Wu, Haijun, Liu, Haixia, Peng, Ruobo, Xian, Dan, Mao, Qi, Dong, Yongqi, Zhao, Yanan, Peng, Bin, Wang, Zhiguang, Hu, Zhongqiang, Zhang, Junwei, Wang, Xueyun, Hong, Jiawang, Luo, Zhenlin, Ren, Wei, Ye, Zuo‐Guang, Jiang, Zhuangde, Zhou, Ziyao, Huang, Houbing, Peng, Yong, Liu, Ming
• Format: Article
• Language: English
• Subjects: Barium titanates; Bilayers; Corrosion prevention; elasticity; Energy harvesting; Ferroelectric materials; Ferroelectricity; ferroelectrics; freestanding oxides; Heterostructures; Materials science; Nanotechnology devices; Oxidation resistance; Plastic deformation; polarization; Shear strain; spring; Springs (elastic)
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202108419

Oxide nanosprings have attracted many research interests because of their anticorrosion, high‐temperature tolerance, oxidation resistance, and enhanced‐mechanic‐response from unique helix structures, enabling various applications like nanomanipulators, nanomotors, nanoswitches, sensors, and energy harvesters. However, preparing oxide nanosprings is a challenge for their intrinsic lack of elasticity. Here, an approach for preparing self‐assembled, epitaxial, ferroelectric nanosprings with built‐in strain due to the lattice mismatch in freestanding La0.7Sr0.3MnO3/BaTiO3 (LSMO/BTO) bilayer heterostructures is developed. It is found that these LSMO/BTO nanosprings can be extensively pulled or pushed up to their geometrical limits back and forth without breaking, exhibiting super‐scalability with full recovery capability. The phase‐field simulations reveal that the excellent scalability originates from the continuous ferroelastic domain structures, resulting from twisting under co‐existing axial and shear strains. In addition, the oxide heterostructural springs exhibit strong resilience due to the limited plastic deformation nature and the built‐in strain between the bilayers. This discovery provides an alternative way for preparing and operating functional oxide nanosprings that can be applied to various technologies. Epitaxial oxide nanosprings are fabricated by etching sacrificial layer. La0.7Sr0.3MnO3/BaTiO3 nanosprings can be extensively pulled or pushed up to their geometry limits back and forth without breaking, exhibiting super‐scalability with full recovery capability. The ferroelectric/ferroelastic domain switching associated with highly coupled strain and polarization provides the tolerance for shape deformation and the energy for recovery.