Superelastic oxide micropillars enabled by surface tension-modulated 90° domain switching with excellent fatigue resistance.

Li, Yingwei; Chu, Kangjie; Liu, Chang; Jiang, Peng; Qu, Ke; Gao, Peng; Wang, Jie; Ren, Fuzeng et al. · Proc Natl Acad Sci U S A · 2021

basic_science · Level V

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Abstract

Superelastic materials capable of recovering large nonlinear strains are ideal for a variety of applications in morphing structures, reconfigurable systems, and robots. However, making oxide materials superelastic has been a long-standing challenge due to their intrinsic brittleness. Here, we fabricate ferroelectric BaTiO<sub>3</sub> (BTO) micropillars that not only are superelastic but also possess excellent fatigue resistance, lasting over 1 million cycles without accumulating residual strains or noticeable variation in stress-strain curves. Phase field simulations reveal that the large recoverable strains of BTO micropillars arise from surface tension-modulated 90° domain switching and thus are size dependent, while the small energy barrier and ultralow energy dissipation are responsible for their unprecedented cyclic stability among superelastic materials. This work demonstrates a general strategy to realize superelastic and fatigue-resistant domain switching in ferroelectric oxides for many potential applications.