Projects per year
Piezoelectrics interconvert mechanical energy and electric charge and are widely used in actuators and sensors. The best performing materials are ferroelectrics at a morphotropic phase boundary, where several phases coexist. Switching between these phases by electric field produces a large electromechanical response. In ferroelectric BiFeO3, strain can create a morphotropic-phase-boundary-like phase mixture and thus generate large electric-field-dependent strains. However, this enhanced response occurs at localized, randomly positioned regions of the film. Here, we use epitaxial strain and orientation engineering in tandem—anisotropic epitaxy—to craft a low-symmetry phase of BiFeO3 that acts as a structural bridge between the rhombohedral-like and tetragonal-like polymorphs. Interferometric displacement sensor measurements reveal that this phase has an enhanced piezoelectric coefficient of ×2.4 compared with typical rhombohedral-like BiFeO3. Band-excitation frequency response measurements and first-principles calculations provide evidence that this phase undergoes a transition to the tetragonal-like polymorph under electric field, generating an enhanced piezoelectric response throughout the film and associated field-induced reversible strains. These results offer a route to engineer thin-film piezoelectrics with improved functionalities, with broader perspectives for other functional oxides.
|Number of pages||8|
|Publication status||Published - Jan 2022|
- 1 Finished
ARC Centre of Excellence in Advanced Molecular Imaging
Whisstock, J., Abbey, B., Nugent, K., Quiney, H. M., Godfrey, D. I., Heath, W., Fairlie, D., Chapman, H., Peele, A., Davey, J. & Wittmann, A.
30/06/14 → 31/03/21
Centre for Electron Microscopy (MCEM)
Flame Sorrell (Manager) & Peter Miller (Manager)Office of the Vice-Provost (Research and Research Infrastructure)