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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 33: Focus Session: (Multi-)Ferroic States V

KFM 33.8: Talk

Friday, March 22, 2024, 12:05–12:25, EMH 225

Intrinsic strain engineering by dislocation imprint in single-crystal BaTiO3 — •Fangping Zhuo and Jürgen Rödel — Department of Materials and Earth Sciences, Technical University of Darmstadt, 64287 Darmstadt, Germany

Dislocations exert significant control over strain, and charge in ferroelectrics, extending beyond the constraints of traditional bulk doping. In these materials, they not only act as nucleation sites for domain formation and pinning centers for the motion of domain walls, but also offer underappreciated potential in bulk ferroelectrics.

Our focus will be on a novel approach to manipulate the mobility of ferroelectric domain walls and piezoelectricity of single-crystal BaTiO3. By employing controlled high-temperature plastic deformation along the [110] direction, we have effectively enhanced the dielectric and piezoelectric coefficient. This was achieved by harnessing the anisotropic interactions between 1D dislocations and 2D domain walls. We will delve into means of minimizing domain instability and extrinsic degradation processes through strategic strain adjustment, balancing in-plane and out-of-plane domain variants. Direct observation of domain-wall pinning of 90° domain walls by dislocations was documented using in situ transmission electron microscopy. We will highlight the innovative application of intrinsic strain engineering in bulk ferroelectrics, demonstrating plastic deformation as a key technique to customize microstructures and functionalities in these materials.

Keywords: Ferroelectrics; Dislocations; Domain wall pinning; Plastic deformation