Polarization Evolution in Morphology-Engineered Freestanding Single-Crystalline BaTiO3 Membranes

The ferroelectric properties in single-crystalline perovskite oxide can be engineered by strain, which is conventionally achieved via interfacial lattice mismatch between a substrate and an epitaxial ferroelectric overlayer. To realize the continuous tuning of strain in ferroelectrics and explore its functionality in the morphology of freestanding membranes, in this study, we have performed a comprehensive investigation on flexible BaTiO3 (BTO) membranes with varied wrinkle patterns. The freestanding BTO membranes can be obtained from the rigid epitaxial heterostructures by water-dissolving the Sr3Al2O6 (SAO) sacrificial interlayer, and the different varied wrinkle patterns are gained by tailoring the mixing ratios of polydimethylsiloxane (PDMS) supporters following the thermal strain and elastic theory. Then, we have found that the spontaneous polarization switching behavior of freestanding wrinkled BTO membranes is curvature-dependent, and the coercive field of BTO can be reduced by 15.03% once it suffers ∼1.34% tensile and compressive strain. Our study provides a convenient and robust approach to morphological changes of ferroelectrics and holds great promising potential for applications in flexible oxide electronics.