Self-Assembled Epitaxial Ferroelectric Oxide Nanospring with Super-Scalability.

Dong, Guohua; Hu, Yue; Guo, Changqing; Wu, Haijun; Liu, Haixia; Peng, Ruobo; Xian, Dan; Mao, Qi et al. · Adv Mater · 2022

basic_science · Level V

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Abstract

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 La<sub>0.7</sub> Sr<sub>0.3</sub> MnO<sub>3</sub> /BaTiO<sub>3</sub> (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.