Dr. Andrei Kholkin
03/04/2025
אודיטוריום ע"ש דויד וואנג, בניין מידן, קומה 3
13:30
Ferroelectric materials are widely used due to their reversible polarization, high dielectric constant, and remarkable piezoelectric and pyroelectric effects. The functionality of ferroelectrics can be extended by using a combination of these materials with ferromagnetics and ionic conductors at the nanoscale dimensions. In this presentation, ferroionic thin films combining ferroelectricity with ionic phenomena of fast charge recombination and electrodic functionalities will be first considered. The concept of tunable polarization in CeO2 thin films induced by the built-in polarization of BaTiO3 (BTO) thin-film interface, which is buried under the CeO2 layer, will be introduced. We found that the ceria layer punctually replicates the polarization of BTO via a dynamic reconfiguration of its intrinsic defects, i.e., oxygen vacancies and small polarons. Tunable oxidative or reducing properties dictated by polarization also arise at such surfaces. This tunability opens up the perspectives of using ferroionics for wireless electrochemically enhanced catalysis. Another example of tunable nanostructures is magnetoelectric (ME) core-shell nanoparticles. These composites prepared by soft hydrothermal synthesis are characterized by excellent biocompatibility and show large ME response mediated by the remote magnetic field. The intriguing physical properties of such structures will be considered and their usefulness for various catalytic and biomedical applications will be shown.