Dislocation engineering in bulk ferroelectrics

• Applicant: Fangping Zhuo, Ph.D.
• Subject Area: Synthesis and Properties of Functional Materials
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 530438323

The key to boosting dislocation technology in brittle ferroelectric ceramics lies in a precise control of these defects (1D dislocations and 2D domain walls) and a deeper understanding of functionalities. This requires the following specific objectives: 1. Establish robust approaches for introduction and control of dislocation structures (density and arrangement) via high-temperature plastic deformation, so that a clear picture of dislocation engineering in model ferroelectrics is drawn. 2. Investigate temperature dependence of dislocation-tuned piezoelectricity, so that the predictive capabilities for operational integrity and lifetime stability of future dislocation-based electromechanical devices is ensured. 3. Disclose detailed dynamic dislocation-domain wall interactions by in situ methods as function of electric field and temperature: use of transmission electron microscopy (TEM), piezoresponse force microscopy (PFM) and multiscale simulation techniques. In-depth mechanistic understanding of the dislocations interacting with ferroelectric domain walls will be computed by phase-field simulations.

• DFG Programme: Research Grants