Phase transition enhanced superior elasticity in freestanding single-crystalline multiferroic BiFeO ₃ membranes

Abstract

The integration of ferroic oxide thin films into advanced flexible electronics will bring multifunctionality beyond organic and metallic materials. However, it is challenging to achieve high flexibility in single-crystalline ferroic oxides that is considerable to organic or metallic materials. Here, we demonstrate the superior flexibility of freestanding single-crystalline BiFeO3 membranes, which are typical multiferroic materials with multifunctionality. They can endure cyclic 180° folding and have good recoverability, with the maximum bending strain up to 5.42% during in situ bending under scanning electron microscopy, far beyond their bulk counterparts. Such superior elasticity mainly originates from reversible rhombohedral-tetragonal phase transition, as revealed by phase-field simulations. This study suggests a general fundamental mechanism for a variety of ferroic oxides to achieve high flexibility and to work as smart materials in flexible electronics.

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

“…In summary, we have demonstrated excellent superelasticity with remarkable fatigue resistance of BTO micropillars. The surface tension-modulated 90°domain switching uncovered in superelastic BTO micropillars is advantageous over the conventional phase transition mechanism, and it is distinct from freestanding BTO membranes as well (6,48). The same mechanism will likely operate in other ferroelectric materials, for example, in PbTiO 3 (49), which is expected to generate even larger recoverable strains.…”

Self‐Assembled Epitaxial Ferroelectric Oxide Nanospring with Super‐Scalability

“…In contrast, the oxide nano-springs may have strong resilience because of their small plasticity. Recently, we discovered super-elasticity in the FE single-crystal membrane of BaTiO 3 16,17 . This unusual property hints that ferroelectrics like BaTiO 3 could be suitable materials to prepare oxide nanosprings which may exhibit superior mechanical and electromechanical properties.…”

Self-Sealing Complex Oxide Resonators

“…Recent developments in releasing epitaxially grown single crystal complex oxides allow them to be thinned down to the unit cell limit, similar to the vdW materials. 27 − 29 Complex oxides in their ultrathin free-standing form are mechanically robust 30 while withstanding strains up to 8%, 31 , 32 are flexible enough to allow large curvatures 33 and have already been demonstrated as viable nanomechanical resonators. 34 , 35 Furthermore, wafer-scale production of thin-film single crystalline complex oxides are being developed 36 which makes them even more appealing for large-scale CMOS compatible fabrication.…”