Dresden 2017 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 11: Ferroics - Domains, Domain Walls and Skyrmions II

DF 11.9: Topical Talk

Mittwoch, 22. März 2017, 12:15–12:45, WIL B321

The electro-caloric effect in BaTiO₃ from first principles — •Claude Ederer — Materials Theory, ETH Zürich, Switzerland

The electro-caloric effect (ECE), a temperature change observed in certain materials under application or removal of an electric field, provides an attractive perspective for future solid state cooling. Here, we use molecular dynamics simulations for a first-principles-based effective Hamiltonian to study the ECE in the prototypical ferroelectric (FE) material BaTiO₃. Our simulations allow to gain a better understanding of the underlying mechanisms and to identify routes for optimizing the electro-caloric response towards future device applications. In particular, we discuss the anisotropy of the ECE for different directions of the applied electric field, and analyze the origin of an inverse effect (i.e. decreasing temperature under application of an electric field) that occurs at FE-FE phase transitions for certain orientations of the applied field. Finally, we explore ways to optimize the caloric response through epitaxial strain in thin films of BaTiO₃. We show that strain can be used to shift the largest caloric response to both higher and lower temperatures, depending both on the type of strain (compressive or tensile) and on the orientation of the applied field.