The ability to reverse or switch the polarization of a ferroelectric thin film through a mechanical force under an atomic force microscopy (AFM) tip offers the exciting possibility of a voltage-free control of ferroelectricity. One of the important metrics for characterizing such a switching process is the critical force Fc required to reverse a polarization. However, the experimentally measured values of Fc display a large uncertainty and vary significantly even for the same ferroelectric film. Here, using BaTiO3 thin films as a model system, we systematically evaluate Fc using a combination of AFM-based experiments and phase-field simulations. In particular, we study the influence of the AFM tip radius, misfit strain, and film thickness on Fc as well as the interplay between the flexoelectric and piezoelectric effects. This work provides a deeper understanding on the mechanism and control of mechanically induced ferroelectric switching and thus guidance for exploring potential ferroelectric-based nanodevices based on mechanical switching.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys